Exam 4 Microbio

enteric route, gastrointestinal tract

-adhering to mucosal membrane and producing exotoxin invading cellos mucosal membrane moving across cells of mucous and infecting cells else where

artificial and active

vaccines

Cytotoxic T cells

Red blood cells dont have MHC-1. MHC molecules waving flags.

Croup

Respiratory condition caused by viral infection that inflames upper airways; usually in small children

streptococcus

S. progenies: number of virulence factors, m protein, exotoxins, capsules. haulurondiasem streptxosyln , teichoic

Syphillis

STD causes by treponema palladium . spirochete. primary, secondary, tertiary. Congenital present in utero when born to a mother with secondary.

Serology

The study of reactions between antibodies and antigens epitope is part of antigen not antibody

gram negative septicemia

gram n bacteria ecoli or pseudomonas present in blood.

Hypersensitivity

not a good thing for immune system type 3: serum sickness, Arthur, kidney damage, rheumatoid arthritis. Lupus, hep C. type 4: contact dermatitis, poison ivy, cosmetics

opportunistic infection

pathogen that takes advagtage of a host with reduced immunity adhesions such as pili and firmbriae are used by bacteria to attach to host cells septic shock can be induced by the release of endotoxins LPS known as endotoxin, part of the cell envelope of gram negative super antigens cause T cells to produce cytokines (not B)

clonal expansion

rapidly dividing and producing many clones. Creation of a large number of B cells that create exact antibody necessary

Humoral Immunity

Type of acquired immunity mediated by macromolecules found in the humours, or the body fluids. Primarily involves B cells and antibodies Two majo function groups: 1) Tag and destroy infections with antibodies: i.e.) suppose you are infected by bacterial pathogen, Salmonella, some of your B cells specifically fight against this kind of infection. This process of clonal expansion will make more of these specific B cells - When B cells activate, they become plasma cells, only cells in the body that produce antibodies and have short lives compared to memory cells -Antibody (Immunoglobulin): Y-shaped protein complex that identifies, opsonizes, and neutralizes foreign invaders, including bacteria and viruses. Once cell has been marked with an antibody, proteins in the complement system can attach to the microbe and destroy it by causing lysis 2) Create memory cells: some B cells are only partially activated; these B cells become memory cells that can last months, years, decades, or even a lifetime. These cells do not produce antibodies, they "stick around" in case the same infection presents itself again. i.e.) chicken pox as a child: you produced memory cells that will last a lifetime, for this reason you are unlikely to get chicken pox again - Memory B cells= long-lived, do not produce antibodies - Plasma cells= short-lived, produce antibodies

HIV Therapy

Typically involves the synergistic effects of multiple enzyme inhibitors to reduce the viral load - No vaccine to prevent HIV prevention - HIV clades i.e) different form of virus might infect people in Africa than the form in N. America and Europe - Mucosal immunity= hard to develop; difficult to boost IgA levels in mucosal membranes to fight viral infection through the mucous membranes - Virus= constantly changing; genes that produce the reverse transcriptase enzyme undergo frequent mutation

Common Cold

Viral respiratory disease caused by rhinoviruses that attach to the respiratory epithelial cells then spread - Increase mucous secretion, produce inflammation, inhibit action of cilia - Symptoms: scratchy throat, headache, cough, nasal discharge, general malaise -Endemic= always present in population - Vaccine= infeasible; too many different types of rhinoviruses

How Antigens Enter the Body

Voluntarily drink, swallow, inhale. Via insect bites, needle injections, breaks in skin, mucous membranes, skin grafts, or organ transplants. - Body develops an autoimmune disease that causes it to treat the body's own cells as antigenic. Body then produces antibodies that bind to the body's own cells, initiating their destruction - Autoimmune diseases: rheumatoid arthritis, lupus, multiple sclerosis

Cholera

Water-borne disease caused by vibrio-cholerae. Bacterium infects the intestinal wall and produces a toxin that results in watery diarrhea

Antibodies

Y-shaped molecules made of four polypeptide chains: two heavy chains (identical to one another) and two light chains (identical to one another). Chains held together by strong disulfide bonds - Bind to specific antigens at variable regions, on the tips of the "forks" in the Y-shape - If an antibody is enzymatically cleave to remove the fork, the forked portion is called the Fab fragment and the straight portion is the Fc fragment - Fab fragment: Region where antigen binds. Binging of the antibody to the antigen marks the antigen for attack by the immune sys. Activates nonspecific defense mechanisms (such as opsonization) that can destroy antigen - Fc fragment: mediates binding to host tissues, immune cells (such as macrophages and natural killer cells), and complement proteins. i.e.) if Fab fragment binds to antigens on a bacterial membrane, the Fc fragment will be "sticking out." Complement proteins, macrophages, and neutrophils can then bind to the Fc fragment and begin to destroy the bacterium - More diversity in the Fab fragment than the Fc fragment -Change fab fragment changes nature of tool

MHC (major histocompatibility complex)

acquired immunity humans coded for a complex of genes called human leukocyte complex. MHC1: Cell mediated immunity. Bind to peptides in cytoplasm. Present a self antigen indicating cell is healthy. When cell infected MHC1 produces foreign antigen. T cells kill infected MHC2: antiogen present cells, macrophages, dendritic, B cells. bind to fragments outside cell. macrophage fights foreign bacteria present portion of digested bacteria on its surface via MHC2 Response via clonal selection

natural vs active

active person intentionally introduces a foreign substance into the body to develop immunity

Reservoir of infection

an environment in which a disease causing pathogen is found on a regular basis. Can be animals, humans, or non-living. Non-living reservoirs of infection (doorknobs or towels)= fomites. Most pathogens are unable to survive outside their host for long

bivalent

antibodies because they bind to two identical antigens at same time. Two identical binding sites. Each antigen binding site recognizes the same epitope, antigenic determinant

agglutination

antibodies bind to insoluble antigens on surfaces of bacterial cells precipitation: antibodies bind to soluble antigens indirect ELISA: HIV indirect enzyme linked antibody attaches to antibody direction enzyme linked antibody attaches to antigen indirect quicker than direct

neutralization

antibodies directly blocking the ability of the antigens to bind to a host agglutination: cross liking between bacteria cell antigens is part of angulation and precipitin are important in immunology as they can be used to detect bacteria infections in blood serum. blood type. opsonization: microbes are coated by serum components for recondition by phagocytes

passive and artificial

antivenin natural and active: infection by microb natural and passive: maternal. igG placenta to fetus. IgA breast milk Exposure to infection results in naturally acquired active immunity

Vaccines

attenuated: not for pregnant people. herd immunity: watered down reaches those who aren't vaccinated inactivated: formald toxoid vaccines: not attenuated vaccines, contain chemicals or thermally modified toxins . Diptheria. Stimulate antibody mediated immunity. antigenic determinants multiple doses. composite bacterium in vaccines recombinant DNA

secondary infection

body infected again. response much quicker due to B cells and memory T cells. Rapid production of antibodies called anamnestic response. IgG major antibody: circulating shorter lag period

monoclonal

cells produce antibodies against specific antigen

Chlamydia

commonly reported sexual transmitted. Chlamydia trachomatic: infective form small. obligate intracellular pathogen. cannot produce own app. Chlamydia bacterium: cell wall, DNA, RNA, ribosomes enters through mucous membranes. elementary body (inactive one body to another) reticulate )(active, larger, phsyioglical: -usually asymptomatic. causes trachoma lymphogranuloma vereneum and pelvic inflammatory disease (no warts).

immune system

consists of organs, cells, proteins, and supporting system that kill or neutralize invaders, react to allergens and chemicals, and monitor the body for cancer

cytopathology

focuses on toxigenic causes of infectious disease at the cellular level immunopathology: immune responses associated w disease

bacteria food poisoning

food intoxication, infested toxins produced by bacteria that have infected food. CLostridium votulinum, staoh aurerus. nasuea crmaping , vomitting

tissue rejection

graft rejection occurs due to immune réponse agissant foreign MHC proteins Graft rejections unlikely im brain, cornea, testes Graft vs host disease can occur due to transplant (kidney, bone marrow)

enterobactericae

gram neg. salmonella. ecoli, shigella. yersinia. lactose fermeners. gasterenteritis, pneummoia, bloody diarrhea. nosocomial

Types of infection

infection growth of pathogen inside host acute infection short and severe. chronic infection over a long time. Hep A is acute Patients, other patients, hospital staff and equipment all contribute to nosomical diseases

Ability to evade hosts immune response

infectious bacteria have mechanisms that help them survive the hosts immune defense proteases: break down IgA virulence factors exchanged through conjugation. transduction. gram neg type 3

Secondary lymphatic tissues and organs

initiate an adaptive immune response by encountering and binding antigens. examples of secondary tissues and organs: 1. lymph nodes: pea-sized organs located through lymphatic system (armpits, groin area). filter lymph for pretense of infections (antigens) initiate response to begin fighting. B cells and T cells interact in the lymph node to process antigen and initiate a response. One way streets 2. spleen: filters blood for the presence of infection (antigens) much like the lymph nodes filter the lymph. Spleen has two components (red and white) white contains lymphocytes that filter blood for infection. red (makes up most of spleen) not involving in filtering for infections, involved in destroying dead red blood cells. 3. tonsils: fight against inhaled foreign pathogens 4. lymphoid tissue: network of loosely attached and connected lymphatic vessels. -gut associated lymphoid: digestive system -bronchial associated lymphoid: near respiratory -mucosa associated: near mucous membranes, gastrointestinal, respiratory, genitourinary, organ cavity, breast -skin associated lymphoid tissue: skin 5. Peyers patches: aggregations of lymphoid tissue found in the intestine and lungs. Covered in epithelium contains microfilm cells (M cells) that internalize the infection. Antigens infect m cells and passed along to underlying immune cells. Allows cells in Peyers patch to fight infection at local level without having to pass antigens through lymph node of spleen 6. appendix small out pocketing at the beginning of the large intestine

Primary lymphatic tissues and organs

involved in production, maturation and differentiation of lymphocytes (bone marrow and thymus two primary lymphatic tissues) Cells in immune system originate in the bone marrow. Mature in marrow or thymus.

Lymphocytes

lymphocytes are not phagocytic -B cells and T cells originate from lymphoid stems and can only form memory cells. main players. both circulate in the blood and present lymphoid organs 1. B cells- produced in bone marrow and mature in bone marrow. activated in lymph nodes 1a. plasma cells- produce antibodies. neutralize viruses and toxins in opsonize bacteria. B cells have surface antibodies that recognize specific antigenic determinants.. when activated produces antibodies of same type 1b. memory B cells- intimate a fast and efficient response upon re-infection by same agent 2. T-cells: produce in bone marrow and mature in thymus 2a. helper T cells; enhance/suppress actions of immune system 2b. cytotoxic T cells; responsible for attacking and killing target cells that have been infected with intracellular pathogens 2c. memory T cells: coordinate a fast and efficient response upon re-infectoin B and T morphologically smiler. both Agranular. different surface receptors 3. Natural killer cells: kill malignant cells and cells infected with pathogens. role in specific and nonspecific. Play role in both innate and acquired immunity.

ligand

molecule that binds to a receptor on a target cell. -immune normally recognizes cells in body as self cells (doesn't kill the,). These cells have molecules on their surface that allow them to interact as ligands with receptors on immune system cells. -transplant take immunosuppressive drugs. immune system recognizes transplant as foreign body, tries to kill. cells of transplant have surface molecules that the immune system does not recognize

obligate vs facultative

obligate: cannot grow outside host. Chlamydia, Rickettsia. falculative: survive and grow inside or outside

immunodeficiency

primary: lack B or t Or phago or complement system, acquired: HIV

Helper T cells

release cytokines to communicate with other cells and amply response HIV binds and neutralized CD4 receptors on helper T. antigen presenting cells (dendritic, macrophages, B cells) cell mediated immunity assist in process by which helper t proliferate helper cells activate cytotoxic

HIV

retrovirus that causes AIDS. destroys CD4 (helper t). die from aids primary: increase immune cells clinical latency: no visible signs symptoms: CD4 helper T falls tramtically HIV produced CD8 (cytotoxin) antibodies even during symptomatic.

HIV replication

reverse transcriptase: synthesizes double stained DNA from signal stranded RNA. integrate (virus becomes provirus) protease= enzyme that cuts proteins during post-translational processing

primary infection

several days, production of small amount of antibodies. Long latent period. iGm first antibody produced. primary antibody upon first exposure to novel antigen

Etiology

study of the cause of disease - According to germ theory of disease, diseases caused by microorganisms

Modes of transmission

- Zooonotic disease: passed from animals to humans i.e) rabies, the plague - Arthopod-borne diseases: spread by insects (mosquitoes, fleas, ticks) or arachnids

Macrophages

-number of different surface receptors that allow them to bind and destroy infectious agents. identity and bind to foreign antigens because they have receptors for cell surface molecules called toll like structures (pills, fimbrrae, lipopolysaccharide) Also have receptor for the fragment crystallizable region of anti bodies (allows identify and bind to antibodies attached to infected cells or invading pathogens) also engulf and destroy cells in antibody mediated phagocytosis, -Macrophages found in skin, liver, kidney, blood, bone, joints, lympnodes, spleen lung brain -Macrophages produce cytokines (specialized protein communication of immune system) -macrophages reside in specific tissues and named according to tissue of residence. Variety of surface receptors and act as antigen presenting cells. -macrophages mature monocytes and play role in antigen presentation

white blood cells

1. dendritic cells: antigen presenting cells (phagocyte). Under skin, mucous membrane, lungs, intestines. Antigen presentation (not phagocytosis). Professional antigen cells (primary purpose to digest foreign invader and present the relevant antigens to T cells . (antigen presenting cells include macrophages and T cells) (phagocytic) 2. neutrophils: phagocytic cells body's defense against extracellular (bacterial, fungal) Major circulating phagocytic cells in body. not involved in antigen presentation. (phagocytic) 3. eosinophils: white blood cells that primarily deal with parasite infections, such as infections by microscopic worms. they are predominant inflammatory cells in allergic reactions. (phagocytic) 4.mast cells: white blood cells that contain granules rich in histamine, an inflammatory compound. Major role in causing allergies (not phagocytic) 5. basophils: allergic response. (release histamine, prostaglandins, serotonin, leukotrienes, inflam involved in allergic response and in hypersensitive (not phagocytic) Eosinophils, mast cells, and basophils can interact with one another

3 major beneficial roles of the immune system

1. fights pathogen: immune system kills infectious agents, including bacteria, fungi, viruses, and protozoans. 2. inactivates toxins and viruses: immune system reacts to live organisms, but also reacts to live toxic organisms. Vaccines (not living organisms) effective because they developed acquired immunity to pathogen so we are more ready to fight upon further exposure 3. monitors cancer: immune system monitors for cancer cells and kills them. body naturally fights cancer. problem occurs when cancer cells grow so fast that the immune system simply cannot keep up.

Acquired immunity categories

1. humoral immunity: (antibody-mediated immunity: antibody-mediated immunity. Against extracellular pathogens. Immunity involves activation of B cells, which produce antibodies and memory cells. New pathogen body produces antibodies to fight. produces memory cells that will help fight infection if you encounter It again. example: chickpox. not get it again bc of acquired immunity against viruses. antibodies: 3rd defense, specific defense mechanism vaccines involves introduction of a modifies virus or bacteria into body for purpose of memory cells. 2. cell mediated immunity: (3rd defense, acquired immunity) against intracellular pathogens. Kind of immunity involves T cycles (cytoplasms toxic T cells and helper T cells. natural killer cells that act as housekeeper killing cells that pose problem for bodies.

immune system two categories

1. innate immunity, body's natural immunity- what you're born with. immune response works the same way against all infections. (fever, inflammation). Newborn doesn't have acquired immunity. But will still have fever and inflammation as response. innate further defined: 1. Acquired immunity: specific, tailor made type of immunity that is perfected over time. new infection you developed acquired immunity. adaptive immunity, specific immunity. (B cells and T cells components of acquired/adaptive) innate immunity provides first and second lines of defense. Acquired immunity is third line.

Anthrax

Acute disease caused by Bacillus Anthracis. Two versions: 1) infection of the skin (common and associated with people working with livestock) 2) infection of lungs (life threatening) - Infection of lungs occur by endospores (can be turned into fine powder, terrorists used anthrax as biological weapon)

Peptic Ulcer

Caused by Helicobacter pylori (bacterium that is well-suited for living and thriving in the stomach) - Able to neutralize acidity in surrounding areas by increasing pH - Produces urease (enzyme that converts urea, natural byproduct of protein breakdown, to ammonia) - Ammonia converted to ammonium hydroxide (basic in solution); increases areas around Helicobacter pylori and allows it to survive

Blood formed elements

Cells in blood, red, white, platelets. All blood formed elements of immune system originate in bone marrow. Bone marrow contains stem cells called hematopoietic stem cells that are origin of blood. 1. lymphoid stem cells: give rise to natural killer cells and lymphocytes (B cells and T cells) 2. myeloid cells: red blood cells, platelets, neutrophils, basophils, eosinophils, mast cells, monocytes, macrophages, and dendritic cells -red blood cells are also called erythrocytes -white blood cells called leukocytes. Primary cells involved in immunity.

hypersensitive response

the immune system produces an exaggerated or overwhelming response. examples: 1. allergies: immune response to chemical or physical substance. (not harmful) (food particles, pollen, dust mites, pet dandruff) 2. autoimmune diseases: causes body to attack self cells, recognizes as foreign invaders. examples autoimmune: 1. Rheumatoid arthritis: body attacks tissues in joints 2. Multiple sclerosis: Body attacks brain and spinal cord cells 3. Juvenile diabetes: body destroys insulin-producing cells in pancreas 4. lupus: body produces antibodies against its own DNA (chronic fatigue)

Second Line of Defense

EXTRACELLULAR KILLING: natural killer cells kill abnormal cells, and phagocytes remove them from the body FEVER: body's core temperature = 37C of 98.6F; when infected by a pathogen, a common response is to increase core temperature to fight infection. Increase in temperature results from increased metabolic activity, muscle contractions, and reduced blood flow to the skin. Body normally sends blood to the skin in order to cool off the inner core; restricting blood flow to the skin therefore keeps the inner core warmer than it would otherwise be

Immunospressive mechanism

Fetus is not rejected in utero because fetal T cells are prevented from functioning in placenta. -incorrect bc maternal T cells are the cells preventing from functioning and would destroy fetus autoimmune diseases result from the activation of self reactive T cells and B cells. rheumatoid arthritis: result of autoimmune disease in which body produces antibodies that attack self tissue

Pyrogens

Fever-inducing compounds that trigger the hypothalamus to increase the body's core temperature. Low grade fever (triggered by pyrogens) is beneficial to fighting infections found within the body. - Interleukin- 1 (IL-1): body's natural pyrogen; produced by the body in response to infection. Hypothalamus responds to IL-1 by inducing fever, rise in body temp. -Bacterial Components: bacterial toxins and components of a bacterium's cytoplasm can be pyrogens -Antibody-antigen complexes: when antibodies and antigens interact with one another, they form immune complexes that result in both inflammation and fever

Antigen

Foreign molecule that can elicit an immune response and react with products of that response. Must be large enough for the body to recognize it - Generally are large, complex molecules not simple ones - Any part of a bacterium can be an antigen (cell wall, capsule, flagella, pili, LPS, other surface sugars, lipids, carbohydrates, proteins) - Fungi, protozoans, viruses, food particles, dust can be antigens

Third Line of Defense

Forms the body's acquired immune response which conveys specific immunity. This type of immunity targets each infection with tailor-made components - Main players in this system are 3 kinds of lymphocytes: B cells, T cells, natural killer cells - Two components of 3rd line defense are humoral immunity (involves B cells and antibodies) and cell-mediated immunity (involves T cells) 1) Tolerance and recognition of self Vs. non-self: immune sys. is able to recognize foreign substances and target them for destruction, while tolerating substances that it recognizes as "Self." - Negative selection: process where developing B cells and T cells become non-reactive to "Self" - B cells and T cells that would react against the body's own tissue are inactivated and destroyed via apoptosis, leading to anergy (a state of unresponsiveness of the body's defense mechanisms, in which the body can't mount a normal immune response against a self-antigen) - Prevents the immune sys, from destroying "Self" cells 2) Specificity: immune sys. reacts in a different way to each of the pathogens it encounters. B cells and T cells have receptors that recognize specific antigenic determinants 3) Heterogeneity: immune sys. is able to produce a unique response to a wide variety of different antigens 4) Memory: immune sys. is able to recognize and quickly respond to antigens that it has previously encountered. Does so by creating memory cells after the primary infection that allow it to quickly and efficiently address a secondary infection

Epitopes (Antigentic Determinants)

Immune sys (particularly B cells, T cells, and antibodies) recognize + bind to epitopes or antigenic determinants. Epitope is the region of the antigen that binds directly to the antibody. - A single bacterium might have several antigenic determinant sites; nearly every part of a bacterium can be an antigen - Body produces antibodies that are specific to certain antigenic determinants - A single bacterium may be several antigenic determinants on its surface, each antigenic determinant will be recognized by only one type of antibody - Proteins are the most antigenic of the major polymers (most vaccines are made of proteinaceous molecules)

5 major classes of antibodies in humans

Immunoglobin A: Major antibody in secretions (saliva, tears, vag fluid, milk) Immunoglobin D: co-expressed with IgM; activation of B cells and basophils IgE: aIllergic reactoins IgG: major circulating antibody. Fe portion of this antibody allows it to cross placenta and enter fetus IgM: First antibody produced duding an immune response IgE: allergy

First Line of Defense (Barrier Defenses)

Includes physical and chemical defenses that prevent pathogens from entering the body. Major components: SKIN: - Inhospitable to potential invaders because it is dry, cool, salty (due to perspiration), has a low pH (due to oily secretions from sebaceous glands), and produces protective secretions that kill bacteria. Perspiration contains lysozyme which destroys the cell walls of bacteria, and other antimicrobial substances. - The epidermis, normal flora, mucous membranes, and mucociliary escalator are all part of the body's nonspecific defenses. - Contains normal flora: population of bacteria and yeast that live on skin + protect against pathogens by competing with them for space + food; synthesize vitamins that the host can use for its own growth + metabolism, help stimulate second line of defense; can be found on skin + in mucous membranes. - Acts as a physical barrier, contains normal flora, involved in perspiration, plays a role in microbial antagonism. Does not fight microbes with macrophages. - Epidermis= top layer: consists of tightly packed layer of dead cells that are constantly sloughed off and regenerated. Regeneration= important, makes it more difficult for bacteria to establish sustainable infection MUSCOUS MEMBRANES: - Of the respiratory, digestive, and urogenital tracts project against foreign invaders; most frequently used as portals of entry for pathogens - Produce mucous: sealant-like layer that covers + protects the cells of the membrane. In some case contain specialized cells that kill foreign invaders before they can enter the body. i.e.) alveolar macrophages (part of body's 1st line of defense) are phagocytes located in the alveoli of the lungs that directly attack and neutralize pathogens - Epithelium= outermost layer; similar to epidermis as it is constantly regenerated. As cells shed from the epithelium, microbes that have attached to the epithelium shed as well (unlike epidermis, epithelium consists of live cells); NOT involved in body's nonspecific defense - Respiratory tract= lined with ciliated cells that beat upward, moving mucous + particles trapped in mucous upward. Mucociliary blanket/ elevator traps + protects microbes from entering the lungs. Once microbes have been brought upward in the res. tract, that are expelled through sneezing and coughing. Can be swallowed in conjunction with saliva, stomach acid will kill the bacteria.

Innate Immunity

Involves non-specific defense mechanisms that respond in the same way to all invading pathogens FIRST line of defense: includes the barrier defenses that prevent pathogens from entering the body in the first place. Includes skin and mucous membranes of the digestive, respiratory, and urogenital tracts SECOND line of defense: includes the non-specific defenses that attack a pathogen once it has entered the body. Includes phagocytosis, extracellular killing, inflammation, fever, and the complement system.

lymphatic system

Lymphatic organs and a conducting network of lymphatic vessels that carry a lymph, colorless fluid containing white blood cells. Network runs parallel to circulatory system. When circulatory delivers blood to organs, some liquid seeps out of capillaries. Lymphatic picks it up and carriers it to heart. T cells, B cells, phagocytic cells exist in lymphatic -Lymph similar to blood except doesn't have red blood cells. Red blood cells to large to leak through capillaries ALl components except red blood cells can move between the blood and lymph vessels

Antibodies in humans

Made possible by: -protein subunits as assembled in pieces. each immunoglobulin has different constant region. Large variety of antibody -DNA rearrangement dramatically increasing variation: rearrangement and recombinant = variety

The complement system

Major part of immune sys. that includes complement proteins that circulate in the blood. These proteins are normal inactive, but can become active in complement fixation (can occur in 3 ways) 1) Classical pathway: relies on antigen-antibody interactions 2) Alternative pathway: does not rely on pathogen binding antibodies 3) Lectin complement pathway: similar to classical; activated by the binding of mannose-binding lectin to mannose residues on pathogen's surfaces - Killing the infection: complement proteins accumulate on the surface of the microbe and drill a hole into it causing it to lyse. Phagocytes can then remove the dead microbe. - Complement proteins bind to + destroy extracellular bacteria - Complement proteins form the membrane-attack complex (MAC): punctures the membrane of the foreign invader by forming transmembrane channels; activation of complement proteins result in formation of a MAC that lyses foreign cells -Complement sys. only attacks extracellular pathogens; does not attack pathogens once they have entered a cell. - If you put red blood cells, antibodies against red blood, and complement proteins in a test tube, you would expect to observe the lysis of the red blood cells - Opsonization: complement proteins can act as opsonins, covering the surface of a microbe and facilitating phagocytosis - Inflammation: complement proteins trigger the production of inflammatory compounds - Chemotaxis: complement proteins act as chemicals that attract immune cells such as phagocytes to the area of the infection - Complement system plays an extremely important role in immunity. Genetic problems with a lack of properly functioning complement system. These people are 10s of 1000s times more likely to get certain infections that lead to conditions like meningitis - Plays a role in both innate immunity and acquired immunity (phagocytic cells and natural killer cells also play a role)

Granulocytes

Mast cells, neutrophils, basophils, and eosinophils= granular; their granules pick up colors if you stain them. They can lose their granules in a process called degranulation Granulocytes include neutrophils, eosinophils, mast cells, and basophils NOT B cells and T cells i.e.) when a cell encounters allergen they release their granules which contain concentrated chemicals; most common= histamine. This produces an allergy response, reason why you have to take antihistamines to fight against allergies. In contrast: monocytes and lymphocytes are agranular: meaning they lack small, compacted particles (granules) Doctors diagnose bacterial infection by looking for heightened levels of polymorphonuclear neutrophils (PMN) or "polys": refers to the fact that have nuclei of different shapes

3 categories of T cells and natural killer cells

Natural killer cells and cytotoxic T cells kill altered cells, infected cells, and cancer cells. Cytotoxic, helper, natural Altered cells: body's cells are altered in a maladaptive way and must be killed Infected cells: cells infected w viruses, fungi, bacteria, and other intracellular parasites killed Cancer cells: body natural fights cancer cells, immune system cant keep up.

Azidothymidline (AZT)

Nucleoside analog reverse transcriptase inhibitor that delays the development of AIDs in HIV patients - Another reverse transcriptase inhibitor= non-nucleoside analog -HIV treatment may include fusion protein inhibitors that prevent HIV virus from entering host cell in the first place

Second Line of Defense INFLAMMATION

Occurs when the cells of an injured tissue secrete chemicals that produce several cardinal signs of infection, including redness, warmth, swelling, pain, and altered function. increases blood flow to the affect tissue, expediting the process of repairing the damaged tissue. - Acute inflammatory response: develops quickly after an injury; it involves the production of chemical mediators that typically promote healing and eliminate invading pathogens by: dilating the capillaries + increasing blood flow to the area. diapedesis (passage of blood cells through capillary walls into the tissues because the capillary walls become porous), restricting the movement of pathogens in order to isolate them, recruiting additional phagocytes in the area, increasing the temperature in the infected tissue (further stimulates the inflammatory response - Chronic Inflammatory response: slower and long-lasting; can be maladaptive and may cause permanent tissue damage Acute= beneficial to body but chronic inflammation can be dangerous because it leads to permanent tissue damage

dental carriers

tooth decay. street. mutant. -break down sucrose, down into its monomers. -form polymers that act like biofilm dextrose increase acidity in infected area. periodontal disease: plague at area where gum joins teeth.

human rabies immune globulin

treatment for rabies gram positive clostridium- no outer membrane, no endotoxin or LPS -symptoms of gangrene include tissues without enough oxygen foul smelling drainage fever. surgically remove dead tissue then antibiotics. -clostridium- causes gas gangrene and food poisoning

Opsonization

Process a pathogenic microbe is marked for phagocytosis by coating it with serum components. Enhances the pathogen's visibility and makes it easier for phagocytic cells to engulf and digest it. The more opsonins present, the higher the degree of binding between the pathogenic microbe and a phagocytic cell i.e.) "sugar coating" a candied apple; more likely to eat the apple if its been covered in candy rather than not - Opsonins: molecules that coat and cover infectious agents in the process of opsonization 1) Antibodies: can bind to the surface of a microbe, which coats it and makes it more likely to be destroyed via phagocytosis 2) Complement proteins: small proteins found in the blood. Some are opsonins, they bind to infectious microbes making it more likely that they will be engulfed (also stimulate the release of cytokines, which initiate the massive amplification of immune cells to fight the infection) 3) C-reactive protein (CRP) and mannose-binding lectin (MBL): acute phase proteins, whose plasma concentrations change due to infection. When a bacterial infection activates macrophages, cytokines are released, stimulating the liver to produce more proteins. Act as opsonins, binding bacterial surfaces + "marking" a pathogen for destruction by a phagocyte

Second Line of Defense PHAGOCYTOSIS

Process which specialized cells (including neutrophils, dendritic cells, monocytes, and macrophages) recognize, ingest, and digest extracellular pathogens. - Basic process: 1) phagocytic cell recognizes and binds to microbe 2) phagocytic cell engulfs microbe, forming a phagosome that brings the microbe into the phagocyte's cell body 3) phagosome fuses with lysosome that contains a mixture of harsh chemicals that digest the microbe (phagolysosome) 4) remnants of the digested microbe (i.e. the microbial debris) are released from the cell through exocytosis - Lysosomes contain a # of harsh chemicals, including hydrolytic enzymes, such as lipases ( break down lipids), nucleases (break down nucleic acids), proteases (break down proteins), and lysozyme (break down bacterial cell walls); contain toxic reactive oxygen intermediaries (including hydrogen peroxide and superoxide) as well as toxic reactive nitrogen intermediaries. All of these are involved in digesting the microbe once the phagosome fuses with the lysosome. Hydrolyic enzymes= important in 2nd line, located in lysosome NOT Golgi body - Phagocytic failure: occurs when phagocytosis does not occur correctly leaving microbes alive when they should be dead. Causes: failure of the phagosome to fuse with the lysosome. failure of the chemicals in the lysosome to kill all bacteria. -Features of phagocytic failure: capsules (polysaccharide layers surrounding bacterial cells. make it difficult for phagocytes to grab bacterial cells during phagocytosis; many disease-causing bacteria have capsules), carotenoids (antioxidants that neutralize the toxic oxidizing agents within lysosomes, including peroxides + superoxides), catalase (enzyme that decomposes hydrogen peroxide to water and oxygen), leukocidins (compounds that kill phagocytic white blood cells)

Herpes

viral disease; can remain dormant in body for a long period before symptoms 1) Oral Herpes (HSV-1)= very common, produces cold sores and fever blisters 2) Genital Herpes (HSV-2)= less common

Phagocytes

Recognize, engulf and destroy foreign cells which stops infection and naturalizes foreign invaders. monocytes, macrocodes, neutrophils, and dendritic. 1. monocytes: mononuclear phagocytic leukocytes circlet around body for about 8 hours before mature into 2. macrophage: identify infection bind to infectious agent. monocytes circle body macrophages typically localized in specific tissues. Kupffer cells are macrophages in liver. alveolar macrophages in lungs, microglia macrophages in brain. kidney mesangial cells in kidney -macrophages are antigen presenting cells. digest and destroy infectious agent, presents antigens to helper T cells. helper T cells bind and recognize "non self antigens

Koch's Postulates

Robert Koch - Only explains infectious diseases not all diseases because some are not caused by microorganisms 1) Observation: scientists must observe that unhealthy organisms contain the microorganism in question 2) Isolation: scientists must isolate the microorganism + grow it in pure culture (a culture with only one species) 3) Re-infection: scientists must infect a healthy organism with the isolated microorganism to cause infection 4) Re-observation and re-isolation: Scientists must isolate microorganism that caused the disease in the infected individual and confirm that it is the same microorganism that was thought to have infected the original unhealthy organism Cases Koch's postulates fall short: 1) Mycobacterium leprae: bacterium that causes leposy cannot be grown quickly outside of its host 2) Treponema pallidum: bacterium that causes syphilis cannot grow outside of its host and thus cannot be isolated in our culture 3) Polymicrobial diseases: caused by multiple microbes so a pure culture is not useful for describing their causes

Haptens

Small organic molecule that only elicits an immune response when attached to a large carrier such as a protein - Do not cause an immune response when they are unattached and on their own, mainly due to the size restriction- antigen must be large enough for body to recognize) - Many drugs are haptens i.e.) penicillin: reacts chemically with blood proteins to form carrier complexes, sometimes leading to a sever, life threatening allergic response called anaphylaxis

Cytokines

Soluble proteins or glycoproteins that act as intercellular mediators or signaling molecules, facilitating intercellular communication. -Intercellular mediators that allow immune cells to communicate with one another -Their functions are divided depending on location of the cells impacted: 1) Play an autocrine function when they act on the same cell that secreted them 2) Play a paracrine function when they act on nearby cells 3) Play an endocrine function when they have a systemic effect, acting on cells far away from the cell that secreted them -Several classes of cytokines: 1) Monokines: released from mononuclear phagocytes, like monocytes 2) Lymphokines: released from T lyymphocytes 3) Interleukins: released by leukocytes; have impact on other leukocytes 4) Colony-stimulating factors (CSFs): stimulate the differentiation of immature leukocytes in the bone marrow, where all immune system cells originate. Allows body to quickly respond to an infection with the appropriate cell types 5) Tumor necrosis factors (TNFs): stimulate the destruction of cells to inhibit tumorigenesis 6) Interferons: special class of cytokines that form the body's primary + first response to viral infection. Don't prevent viruses from entering the host cell, but prevent new viruses from replication + assembling. Get their name because they interfere with viral replications. Help regulate immune response