Ch. 22 Lymphatic and Immune System

Spleen (on LT side of the abdomen) is where lymphocytes check

Blood for bacteria, viruses and debris

Formation and flow of lymph

Blood plasma -> Interstitial fluid -> Lymph capillaries -> Lymph vessels -> Lymph nodes for filtration -> Lymph trunks -> Lymphatic ducts -> Subclavian veins

Fluid and plasma must be returned to keep ___/___ maintained and to prevent edema

Blood volume/blood pressure

Homeostatic imbalance of lymph nodes- Swollen lymph nodes

Buboes- overwhelmed lymph nodes, large number of bacteria and viruses

___ are broken down into small fragments that associate with MHC molecules

Antigenic proteins

Complement fixation and types

Attachment of protein to foreign body, activates the protein - Membrane Attack Complexes -Opsonization

Lymphoma

Benign or malignant tumor of lymphoid tissue - Non-Hodgkin Lymphoma - Hodgkin disease

Plasma cell (lymphocyte)

Descendant of B cell that produces and secretes antibodies.

Memory B cell (lymphocyte)

Descendant of B cell that remains after immune response and is ready to respond rapidly and forcefully should the same antigen enter body in future.

B cell (lymphocytes)

Differentiates into antibody producing plasma cell.

Passive humoral immunity

Differs in Ab source and degree of protection •Ab obtained from an immune human or animal donor •B cells are not activated, no memory, protection ends when Ab degraded

Pathogen

Disease causing microorganism

Thymus gland (lymphoid organ) peak function

During childhood (large in the infant and after puberty is large replaced by adipose and areolar connective tissue)

Immunogenicity

Stimulate proliferation of specific lymphocytes and Antibodies •Antigenic determinants(epitopes)- immunogenic parts of an antigen, can have multiple types •Plastics have few determinants and are used for artificial implants

Self

Not seen as a threat

House the immune cells

Organs and tissues

Remaining fluid from hydrostatic pressure becomes

Part of interstitial fluid between cells

Immune cells

Phagocytic cells and lymphocytes

B lymphocytes

Plasma and memory cells

Memory T cells (or memory cytotoxic T cells)

Remain to provide quick action at next exposure to same antigen

Memory T cell (lymphocytes)

Remains in lymphatic tissue and recognizes original invading antigens, even years after first encounter.

Splenectomy

Removal of spleen when hemorrhaging - Less common today, found to heal itself and regenerate in children

Immunology

Study of the immune system (specific defense)

The ___ is then inserted into the membrane of a body cell (antigen presentation)

antigen-MHC complex

Which of the following conditions is a tropical disease where lymphatics are clogged with parasitic roundworms resulting in edema of enormous proportions? a. Hodgekins disease b. Elephantiasis c. Buboes d. Non-Hodgkin lymphoma

b. Elephantiasis

True or False: High fever is beneficial and not dangerous. a. True b. False

b. False

Which of the following is a primary lymphatic organ/tissue? a. Spleen b. Red bone marrow c. Lymph nodes d. Peyer's patches

b. Red bone marrow

Where can the Peyer's patches be found? a. Kidneys b. Small intestine c. Pancreas d. Throat

b. Small intestine

Which of the following destroys and stores breakdown products of old red blood cells, acts as a blood reservoir, and stores platelets? a. Thymus b. Spleen c. Red bone marrow d. Lymph nodes

b. Spleen

Which of the following is the site of T-Cell maturation? a. Lymph nodes b. Thymus c. Spleen d. Tonsils

b. Thymus

Which of the following drains roughly 75% of all of the body's lymph? a. Left lymphatic duct b. Brachiocephalic trunk c. Thoracic duct d. Right lymphatic duct

c. Thoracic duct

Breast milk provides an infant with with antibodies helping to protect the infant. This type of immunity is a. artificial active immunity b. artificial passive immunity c. natural passive immunity d. natural active immunity

c. natural passive immunity

Which of the following can be found within our body's first line of defense? a. antibodies b. complement c. skin and mucous membranes d. phagocytes

c. skin and mucous membranes

Antigens are substances recognized as

foreign that provoke immune responses (ANTIbody GENerating)

Membrane Attack Complexes

formed by complement fixation, proteins form holes in cell membrane for lysis

Complete antigens functional properties

immunogenicity and reactivity

Secondary lymphatic organs and tissues

lymph nodes, spleen, lymphatic nodules (tissues)

The body system that carries out immune responses is the

lymphatic system

Lymph nodes are clustered along

lymphatic vessels that filter lymph

Slow flow through node allows

lymphocytes and macrophages to do their job

Lymphatic nodules are

masses of lymphatic tissue that are not surrounded by a capsule

Complement proteins

•20-30 plasma proteins in blood •Amplify inflammatory response, cause cell lysis, promote phagocytosis

5. Fever

•Abnormally high body temp. •Pyrogens- chemicals secreted by WBCs and macrophages, cause body temp. to increase

Physical and chemical barriers of 1st line of defense

•Acidic pH of skin secretions and sebum inhibits bacteria growth •Hydrochloric acid and digestion enzymes of the stomach •Saliva and lacrimal fluid (lysozymes) •Sticky mucus traps pathogens in respiratory and digestive tracts and cilia work to move the substance out

Organs and tissues house the immune cells and are known as

"wastewater treatment system"

Opsonization

(coating of microbe)- causes membranes to become sticky, easier for adherence (phagocytosis)

Homeostatic imbalances: Transplants

- Autograft- tissue graft from one place to another in same person - Isograft- genetically identical tissue donated (twin) - Allograft- tissue taken from non-related person (most common) - Xenograft- tissue taken from another species

Components of the lymphatic system

- Blind lymphatic capillaries - Lymphatic vessels - Lymphatic nodes - Lymphatic trunks - Lymphatic ducts

Disorders- AIDS (Acquired Immunodeficiency Syndrome)

- Caused by human immunodeficiency virus (HIV) transmitted in body fluids •Destroys Helper T cells depressing immune response •Cytotoxic T cells mount initial response but become unresponsive to viral cues •Virus multiplies in lymph nodes

Structure of antibodies

- Consist of 4 polypeptide chains •Differ in structure - Variable and Constant regions

Lymphocytes

- Cytotoxic T cell - Helper T cell - Memory T cell - B cell - Plasma cell - Memory B cell

APC(antigen presenting cells) that engulf antigen and present fragments on their membrane to T cells

- Dendritic (Langerhans) cells in skin - Macrophages - Activated B lymphocytes

Other functions of spleen

- Destroys and stores breakdown products of old RBCs - May produce RBCs in fetus - Act as a blood reservoir, stores platelets (1/3) and monocytes

Lymphatic system functions (3)

- Drain interstitial fluid - Carry out immune responses - Transport dietary fats

Immune system two defense systems

- Innate (nonspecific) system; First and Second line of defense, always ready - Adaptive (specific) system; Third line of defense, must be primed; Attacks particular foreign substances

2 types of antimicrobial chemicals

- Interferon (IFN) proteins - Complement proteins

Homeostatic imbalances: Rejections

- MHC and tissue rejection - Patient receives immunosuppressive therapy •Corticosteroids (suppress inflammation), cytotoxic drugs, radiation therapy, immunosuppressor drugs •Prone to infections

Phagocytes types

- Macrophages- derived from monocytes - Neutrophils- become phagocytic upon encountering foreign substance - Eosinophils- weak phagocytes, defend against parasitic worms

Types of passive humoral immunity

- Natural- fetus gets passive immunity from mother that lasts several months after birth - Artificial- given immune serum •Given after hepatitis exposure •Immune sera after snake bite, botulism, rabies, hepatitis exposure Effects short-lived (2-3 wks)

Types of active humoral immunity

- Naturally acquired during infections - Artificially acquired with vaccines- contain dead or attenuated (weakened) pathogens, prime the system •Spared most of the symptoms of disease •Promotes immunological memory by providing antigenic determinants that are reactive and immunogenic •Hepatitis B, pneumonia, smallpox, polio, tetanus, diphtheria, measles

Immediate Hypersensitivities

- Reaction can be local or systemic - Begins in seconds, lasts ~ ½ hour - No symptoms on first encounter; B cells produce vast amounts of Ab - Second exposure causes basophils to release histamine •Causes runny nose, redness, itching, watery eyes - Inhaled or ingested allergens •inhaled- cause smooth muscle constriction, asthma •ingested- abdominal discomfort •treated with over-the-counter drugs, containing antihistamine

Lymphoid tissue - Tonsils

- Small masses of tissue, ring the throat - Trap foreign pathogens entering throat - Tonsillitis - red and swollen due to excess bacteria

Homeostatic imbalance of lymph nodes- Secondary cancer sites

- Some cancers use lymphatic system to spread - Swollen glands are usually painless making them distinguishable from inflamed glands

Lymph nodes

- Surrounded by CT (connective tissue) capsule - Contain lymphatic nodules made up of B cells - More afferent vessels than efferent vessels - slow flow - All lymph flows through more than one lymph node - Contain reticular fibers that act as a filter

Some of the cells inside of a lymph nodes

- T cells - Dendritic cells - B cells - Macrophages

Lymphoid tissue - Peyer's patches

- Wall of small intestines (ilium) - Prevent foreign substances from entering intestinal wall

Buboes cause and is a *** function

- inflammation and tenderness - Swelling during infection is a trapping function

Plasma cells

-B cell descendant, secrete Ab -Produce much more antibody (Ab) than B cell •Produce 2000 molecules per second •Last 4-5 days

2nd line of defense components (5)

1. Phagocytes 2. NK cells 3. Inflammatory response 4. Antimicrobial chemicals 5. Fever

Which of the following cells requires antigen-presentation to be activated? a. T cells b. B cells c. macrophages d. all of the above

A. T cells

Which of the following filter lymph? a. lymph nodes b. lymphatic vessels c. spleen d. all of the above

A. lymph nodes

Neutralization

Ab binds bacterial exotoxins (secreted toxic chemical) rendering it harmless

Route of flow through a lymph node

Afferent lymphatic vessel -> Subcapsular sinus -> Trabecular sinus -> Medullary sinus -> Efferent lymphatic vessel

Lymph enter through

Afferent lymphatic vessels, flow through node, exits at hilus by efferent lymphatic vessels

Non-Hodgkin's Lymphoma

All cancers of lymphoid tissue except Hodgkins lymphoma, due to lymphocytes, 7th most common cancer, often occurs in young people

For an immune response to occur,

B cells and T cells must recognize that a foreign antigen is present

Antibody-mediated

B cells mature in the bone marrow

Breast milk provides an infant with antibodies helping to protect the infant. This type of immunity is a. natural active immunity b. natural passive immunity c. artificial active immunity d. artificial passive immunity

B. natural passive immunity

Filtered lymph is returned to the blood at the a. right atrium b. pulmonary veins c. subclavian veins d. left atrium

C. subclavian veins

Helper T cells

CD4 cells, director - Release chemicals that recruit other cells to fight (Macrophages, B cells, T cells) - Release cytokines (Stimulates T cell and B cell growth; Attracts other WBCs; Enhances innate defense system)

Cytotoxic (killer) T cells

CD8 cells •Virus, cancer cells, grafts •Insert toxins (perforins) into foreign cell membrane

Lymphatic capillaries which are closed on one end, are located between

Cells of many tissues

Lymphatic capillaries are

Closed on one end

Agglutination

Clumping of foreign cells by cross-linking

Antigens types

Complete or incomplete

Helper T cell (lymphocyte)

Cooperates with B cells to amplify antibody and secretes interleukins, which stimulates proliferation of T cells and B cells. May secrete tumor necrosis factor (T N F), which stimulate inflammatory response.

Precipitation

Cross-linking becomes so large complex settles out of solution

Tropical disease where lymphatics are clogged with parasitic round worms resulting in edema of enormous proportions

Elephantiasis

Sentinel node

First node that receives lymph drainage from a suspected cancerous area, biopsied to determine if cancer has metastasized into lymph tissue

Hydrostatic pressure (BP) in capillary beds forces

Fluid and some plasma proteins out

Vessels transport

Fluids back to the blood

Nonself

Foreign, threat

The immune system

Functional system rather than organ system

•Genetically engineered ___ used to combat Hepatitis C, herpes, and viral infections in organ transplants

IFNs

Variable region forms 5 major classes in order of abundance

IgG, IgA, IgM, IgD, IgE [GAMDE (Go And Make Donuts Early!)]

Primary lymphatic organs are where

Immune cells become immunocompetent - Red bone marrow (B cells) - Thymus (T cells)

Adaptive immunity, third line of defense

Immune response to antigens

Disorders: Autoimmune diseases

Immune system attacks self-antigens, damages own tissue - Multiple Sclerosis- myelin sheaths - Myasthenia gravis- neuromuscular - Grave's disease- thyroid gland - Type I diabetes mellitus- pancreas - Systemic lupus erythematosus (SLE)- kidneys, heart, lungs, skin - Glomerulonephritis- kidneys - Rheumatoid arthritis- joints

There are large clusters of lymph nodes in

Inguinal, axillary, and cervical regions

Leukocytosis

Injured cells produce leukocytosis-inducing factors, causes neutrophil release from bone marrow

Inflammatory response: Injured cells

Injured cells release chemicals •Histamines, kinins, prostaglandins, complement, and cytokines

Cytotoxic T cell (lymphocyte)

Kills host target cell by releasing granzymes that induce apoptosis, perforin that forms channels to cause cytolysis, granulysin that destroys microbes, lymphotoxin that destroys target cell DNA, interferons that attracts macrophages and increases phagocytic activity.

phagocyte mobilization

Leukocytosis -> Margination -> Diapedesis -> Chemotaxis

Lymph vessels pass through lymph nodes and then merge into

Lymph trunks

Lymph capillaries merge to form

Lymphatic vessels which convey lymph into and out of lymph nodes

Lymphatic capillaries merge to form

Lymphatic vessels which have thin walls and many valves

Antigen- Presenting Cells (APCs)

Macrophage Dendritic cell B Cell

*** remove, "filter", foreign material (from lymph)

Macrophages

Hodgkin disease

Malignant lymphoid tissue, malignant B cells, non-painful swollen lymph nodes, genetic and mononucleosis predisposing factors

Flow through node is slow due to

More afferent vessels than efferent

Complement fixation

Most common; activation leads to cell lysis

Secondary lymphatic organs are the sites where

Most immune responses occur

Immunocompetence

Mounting an immune response

Diapedesis

Neutrophils squeeze through capillary wall

Margination

Neutrophils travel to inflamed site, stick to capillary wall

Nonspecific Resistance (Innate Immunity) is present and includes

Present at birth and includes defense mechanisms that provide general protection against invasion by a wide range of pathogens and their toxins

Dendritic cell (APCs)

Processes and presents antigen to T cells and B cells; found in mucous membranes, skin, lymph nodes

B cell (APCs)

Processes and presents antigen to helper T cells.

Macrophage (APCs)

Processing and presentation of foreign antigens to T cells; secretion of interleukins and interferons (induces proliferation of B cells and T cell growth.)

Antigen

Protein (self or foreign) substance, recognized by immune system

Antibody

Protein that tags a foreign substance

Self-antigens

Proteins found on our cells, don't usually activate immune response - Major histocompatibility complex (Human leukocyte antigens) - May be antigenic to other people (transplants)

Interferon (IFN) proteins

Proteins produced by virus-infected cells diffuse to nearby cells to induce synthesis of antiviral proteins - prevent replication

RT lymphatic duct empties into -> Thoracic duct empties into ->

RT subclavian vein LT subclavian vein

Inflammatory response

Response to tissue damage, includes pain, redness, immobility, swelling, and heat (PRISH)

First line of defense

Skin and mucous membranes

Antibodies (aka immunoglobulins- Igs)

Soluble proteins secreted by B cells that bind to antigens

Adaptive immunity has both ___ and ___ and is divided into 2 types

Specificity and memory; Cell-mediated & antibody-mediated

Thymus gland is the site of

T cell maturation

Cell-mediated

T cells mature in the thymus

Lymph trunks merge to form

The thoracic duct or RT lymphatic duct

Thymus gland produces

Thymosin and thymopoietins that function to program lymphocytes (T cells)

Active humoral immunity

When B cells are challenged and produce Ab

Inflammatory response: effects

a)Prevents spread of damage (clotting factors) b)Disposes of cell debris and pathogens •Neutrophils and Monocytes squeeze through blood vessels (diapedesis) to damaged area to clean debris c)Sets stage for repair (fibrin mesh)

Which of the following form "Membrane Attack Complexes"? a. Complement proteins b. Antibodies c. Interferon d. NK cells

a. Complement proteins

Which of the following is NOT one of the classes of immunoglobulins? a. IgS b. IgG c. IgM d. IgE

a. IgS

Which of the following filter lymph? a. Lymph nodes b. Spleen c. All of the available answer options are correct d. Lymphatic vessels

a. Lymph nodes

Which of the following is an example of MALT? a. Tonsils b. Spleen c. Lymph nodes d. Thymus

a. Tonsils

True or False: Lymph flows through several lymph nodes before returning back to the cardiovascular system. a. True b. False

a. True

Adaptive immunity involves

activation of specific lymphocytes that combat a particular pathogen or other foreign substance

Which of the following is the most common type of transplant? a. Xenograft b. Isograft c. Allograft d. Autograft

c. Allograft

Which cells are the major mediators of the humoral immune system? a. Macrophages b. T-cells c. B-cells d. NK cells

c. B-cells

Cytotoxic T cells are often called a. CD1 T-cells b. CD4 T-cells c. CD8 T-cells d. CD2 T-cells

c. CD8 T-cells

Which of the following would be the biggest type of vessel? a. Lymphatic capillaries b. Lymphatic trunks c. Lymphatic ducts d. Lymphatic arteries

c. Lymphatic ducts

PRISH is an acronym that is used to help us remember the signs of inflammation. The "R" in PRISH stands for a. Rugged b. Rich c. Redness d. Rash

c. Redness

Which of the following is NOT an APC? a. Dendritic cells b. B cells c. T cells d. Macrophages

c. T cells

Which of the following is FALSE regarding lymph nodes? a. They contain reticular fibers that act as a filter b. They are surrounded by a connective tissue capsule c. They have more efferent vessels than afferent vessels d. They contain lymphatic nodules made up of B cells

c. They have more efferent vessels than afferent vessels

Lymph flows through several nodes before

cleaning is complete

The innate immune system includes which of the following? a. 1st line of defense b. 2nd line of defense c. 3rd line of defense d. 1st and 2nd lines of defense e. 1st, 2nd, and 3rd line of defense

d. 1st and 2nd lines of defense

Which of the following includes phagocytes, NK cells, and fever as defense mechanisms? a. 4th line of defense b. 1st line of defense c. 3rd line of defense d. 2nd line of defense

d. 2nd line of defense

Which of the following is(are) functions of the lymphatic system? a. Transport dietary fats b. Drain interstitial fluid c. Carry out immune responses d. All of the available answer options are correct

d. All of the available answer options are correct

Which of the following cells destroys virally infected cells using granzymes and perforin? a. CD4 T-cells b. Macrophages c. B-cells d. CD8 T-cells

d. CD8 T-cells

Which of the following is an autoimmune condition that affects the kidneys? a. Myasthnia Gravis b. Multiple Sclerosis c. Grave's Disease d. Glomerulonephritis

d. Glomerulonephritis

Which of the following refers the our "non-specific" immune system that we are born with? a. Cell-mediated immunity b. Adaptive immunity c. Humoral immunity d. Innate immunity

d. Innate immunity

Filtered lymph is returned to the blood at the a. Right atrium b. Left atrium c. Pulmonary veins d. Subclavian veins

d. Subclavian veins

Which of the following cells requires antigen-presentation to be activated? a. B-cells b. All of the available answer options are correct c. Macrophages d. T-cells

d. T-cells

Which of the following is TRUE regarding complete antigens? a. The require a binding protein in order to stimulate an immune response b. Lipids make the strongest complete antigens c. They gain immunogenicity when linked with a self-protein d. They display both immunogenicity and Reactivity

d. They display both immunogenicity and Reactivity

Which of the following is an example of artificially-acquired active immunity? a. Infections b. All of the available answer options are correct c. Anti-venom d. vaccines

d. Vaccines

Adaptive immunity refers to the body's ability to

defend itself against specific invading agents (bacteria, viruses, transplants, self-cells that have mutated)

Lymphatic nodules in the GI, urinary, and reproductive tracts and the respiratory airways are referred to as

mucosa-associated lymphatic tissue (MALT)

Most fluid and plasma proteins forced out by hydrostatic pressure is

reabsorbed at venous end

Reactivity

react with lymphocytes and Antibodies

Lymphocytes are produced in

red bone marrow

The lymphatic system consists of

several structures and organs that contain lymphatic tissue, bone marrow, and a fluid called lymph that flows within lymphatic vessel

2 types of lymphatic ducts

thoracic duct and right lymphatic duct

Lymphatic nodules are scattered

through the lamina propria of mucuous membranes lining the GI, urinary, and reproductive tracts and the respiratory airways

How are lymphocytes activated?

when they encounter foreign antigens

Homeostatic imbalances: Allergies

•Allergies occur when a person is overly reactive to a substance that is well-tolerated by most others •When an allergic reaction occurs, so does tissue damage •There are sub-types of hypersensitivity reactions; based on the allergen and the response

In cell-mediated immunity

•An antigen is recognized and bound •Clonal Selection - A small number of T cells proliferate and differentiate into a clone of effector cells •The antigen is eliminated

Allergen enters blood

•Anaphylactic shock, systemic response •Bee stings, spider bites, penicillin •Epinephrine used to reverse histamine effects

Antibody-Mediated (Humoral) Immune Response: B cells

•Antigen is recognized and bound •Helper T cells co-stimulate the B cell to proliferate and differentiate •B cell grows and multiplies rapidly to form army of identical cells (clones) •Produces Plasma and Memory cells •Antigen is eliminated

Adaptive immunity, 3rd line of defense characteristics

•Antigen specific •Systemic- not restricted to initial infection site •Memory- mounts stronger attacks on previously encountered pathogens

Memory cells

•B cell descendants that aren't plasma cells •Long-lived, fewer made than plasma cells •Responsible for immunological memory for the next time an antigen is encountered

Inflammatory response: Chemical effects

•Blood vessels dilate causing hyperemia- redness and heat •Exudate seeps out of capillaries- fluid with clotting factors and antibodies, swelling and pain •Chemotaxis- attract phagocytes and WBCs

Activity of cytotoxic T cells

•CD8 cell binds to target cell and releases granules with perforins •Perforins insert into membrane forming pores •Granzymes enter pores and degrade cellular contents CD8 cell detaches and hunt

IFN effects

•Cause uninfected cells to produce the enzyme PKR protein that interferes with virus replication •Activate Macrophages and NK cells

phagocytosis 5 stages

•Chemotaxis •Adherence •Ingestion •Digestion •Killing

Immune system functions to protect body

•Direct- cell attack •Indirect- mobilizing chemicals and antibodies

Phagocytes

•Engulf foreign substances •Digest particles with enzymes in lysosomes

Functions of antibodies

•Forms antigen-antibody complex to tag for destruction •Neutralization, agglutination, precipitation, and complement fixation

Disorders- AIDS continued

•HIV multiplies in lymph nodes and can invade brain •Antiviral drugs (AZT) inhibit enzyme HIV needs to multiply •Combination drug therapy postpones drug resistance •Ultimately die from overwhelming infection or cancer

Aging and the immune system results in

•Increased susceptibility to infections and malignancies •Increased production of autoantibodies •Decreased response to vaccines •Decreased immune system function

Disorders: Autoimmune diseases triggers

•Ineffective lymphocyte programming •Self-reactive B or T cells not eliminated, escape

Chemotaxis

•Inflammatory chemicals recruit neutrophils to precise location •Monocytes follow Neutrophils and develop into Macrophages

Mild to moderate fever

•Liver and spleen gather iron and zinc, bacteria need these nutrients to multiply •Increases metabolic rates to speed up repair processes

Secondary humoral response

•More effective, bettered prepared, faster •Ab blood levels peak 2-3 days and at higher levels (titer) than primary response

Inflammatory responses (4)

•Pus •Acute inflammation •Chronic inflammation •Abscesses and Ulcers

Two lines of NON-SPECIFIC defense

•Skin and mucous membranes •Internal defenses

Delayed hypersensitivities

•Slow; begin 1 to 3 days after exposure •Involves cytotoxic and helper T cells •No Antibodies •Cytokines released (instead of histamine) •Corticosteroids used to provide relief •Allergic contact dermatitis •Haptens diffuse through skin •Poison ivy, heavy metals, cosmetic chemicals, tuberculosis tests

Cytotoxic (subacute) hypersensitivities

•Slower onset; •begins 1 - 3 hours after exposure •may last 10 - 15 hours •Mismatched blood transfusion

Incomplete antigens (haptens)

•Small molecules that have reactivity but not immunogenicity •Gain immunogenicity when linked with a self protein, results in allergies

2. Natural killer (NK) cells

•Type of lymphocyte, found in blood and lymph •Lyse and kill a variety of cancer cells and virus-infected cells (not specific) •Release chemicals called perforins that cause the target cell to disintegrate •Secrete chemicals that enhance inflammatory response

High fever

•dangerous due to denaturation- proteins (enzymes) break down

Incomplete antigens structure

•peptides, nucleic acids, hormones, and chemicals Poison Ivy, dander, detergents, cosmetics

Complete antigens structure

•proteins (strongest), carbs, lipids, nucleic acids •Pollen grains and microorganism surfaces have foreign macromolecules