Specific Immune Response - Week 2
complement system
(c1-c9) once activated, participates in virtually every inflammatory response. enhances basophils/mast cells to release inflammatory mediators, chemotaxis, phagocytosis, increases vascular permeability and cellular lysis. can be activated in 2 ways but always mediates inflmmation.
IgE
-0.002% of antibodies -primarily involved in inflammation, allergic responses, and -combating parasitic infections -found in serum -mediates the release of vasoactive amines stores in basophils and mast cells (histamine and serotonin)
IgD
-0.2% of total antibodies -found primarily on b-lymphocyte surfaces that serves as antigen receptor - helps induce B-lymphocyte development, and may help control lymphocyte activation or suppression
IgM
-10% of total antibodies -largest of 5 antibody units bound in a circle -cannot cross membranes and usually found in vascular system - first antibody to develop in response to an antigen (primary response) first antibody formed by babies - presence denotes current infection - involved in ABO antibody formation - can activate complement system
IgA
-15% of total immunoglobulins -dimeric (2 basic antibody molecules stuck together) -secretory immunoglobulins which defends external body surfaces. -found in saliva, blood, colostrum, bronchial, prostatic, vaginal, and gastrointestinal secretions -prevents antigens from attaching to epithelial surfaces
IgG
-75% of circulating antibodies (most abundant and smallest) -able to move across membranes like placenta -formed after subsequent contacts with antigens or during secondary immune response -presence denotes past infections -has antiviral, antibacterial, and antitoxin properties and is able to activate complement system -has 4 subclasses
humoral immunity is mediated or controlled by what?
-b-lymphocytes which mature in the bone marrow -develop into plasma cells when stimulated by antigen on the mature B-cells that produce antibodies -they are activated to attack by the T-helper cells
Class I Major Histcompatibility Complex Molecules
-found on almost all cells in the body that have nucleated body cells (not erythrocytes) -capable of altering immune system of cell changes due to viruses and cancer -cell surface glycoproteins that interact with CD8 molecule on cytotoxic T cells -activate cytotoxic T cells -presents viruses, intracellular bacteria, and cancer cells to cytotoxic t cells
Class II Major Histocompatibility Complex Molecules
-found primarily on antigen presenting cells (APCs) -presents an epitope to T-helper cells -assist in development of immune memory because the T-helper cell can develop T-helper memory cells, and stiumlate the development of memory b-cells and plasma cells
b cells
-ingest antibody-antigen complexes and present the antigen peptide to the T-helper cells -the t helper cells then release cytokines that stimulate the multiplication and maturation of antigen-activated B-cells
Suppressor T Cells
-inhibit both humoral and cell mediated immune responses by decreasing the activity of t and b lymphocytes -helps slow down overactive response to avoid damage to normal tissue prevents formation of auto-antibodies ex. when patients receive transplants
natural killer cells
-involved in cell-mediated immunity -do not need to recognize a specific antigen before being activated. -involved in the recognition and killing of virus-infection cells, tumor cells, and transplanted grafts. - large lymphocytes with granular cytoplasm and have CD16 and CD94 surface markers
dendritic cells
-mature cells that reside in the tissues that are exposed to the external environment/ where antigens enter like the skin which are known as lagerhans cells -have atypical shape with extensive dendritic processes - capture antigens at their point of entry into the body and transport them to t-lymphocytes (tcells)
cell mediated immunity functions
-protection against viruses, intracellular bacteria, and cancer cells -macrophages work with cell mediated immune system to effect response -the T-lymphocytes can live from days to years and accounts for longer term immunity -T-lymphocytes also secrete cytokines to recruit other cells of the immune system
Helper T cells
CD4+ cells -serve as the master switch for the immune system, activation of t helper cells causes stimulation of both the humoral and cell-mediated immunity (w/o them the immune system is not effective) -produce and release multiple cytokines that regulate the activity of the other cells of the immune system
cytotoxic T cell cells
CD8+ cells -identify and destroy abnormal body cells -they recognize abnormal cells by interaction with an MHC I surface receptor-antigen complex -kills cells either by inducing apoptosis or by releasing toxic chemical on to the affected cell by toxic cytokines, perforins -very important to control cells infected with intracellular bacteria or viruses IL-2 released from t helper cells increases growth
Major Histocompatibility Complex Molecules
Coded by genes on chromosome 6 evolved to allow cell to cell interaction through sitting on cell surface and capable of stimulating an immune response. Serve as a universal product code or cellular fingerprint for that person. Self or nonself? Broken down into classes (I&II)
types of B lymphocytes include
Plasma cells and memory cells
Haptens
a foreign substance that isnt large enough to be an antigen. must be combined with other proteins to elicit an immune response. usually less than 10,000 daltons in weight
what are antibodies? aka? produced by? classes?
a substance (glycoproteins) made by B-cells that destroy or inactivate a specific antigen. aka immunoglobulins produced by plasma cells in response to a challenge by an antigen 5 classes: IgG, IgA, IgM, IgD, IgE
memory T cell
after exposure to an antigen, these cells develop and continue to circulate in small numbers allow for quick response on second antigen challenge able to clone rapidly
factors that influence innate and specific immunity
age - skin, thymic involution, less secretions, less interleukins, thinner skin, increased self recognition species - variation between species like cowpox nutritional status - immunosuppressed by malnutrition, eldery with feeding difficulties experience problems therapeutic modalities - drugs can cause indirect/direct effect on immune system like steroids, chemotherapy, transplants, opioids, NSAIDS stressors - stress response alters the activity of the immune response because we release cortisole that decreases responses.
memory cells do what?
allow for a quick response to a known antigen on subsequent re-exposure can be an exaggerated response on re-exposure.
development of specific immunity steps
antigen recognition cytokine secretion activation, proliferation, and differentiation of t-cells & b cells destruction of antigen
what are the 2 ways the complement system can be activated?
antigen-antibody complexes - classical microbial mannose sugars or polysaccarides - alternative
how does the immune system interact with antigens? how many do they have? also known as?
antigens have receptor sites called epitopes which allow the immune system to recognize the antigen (pathogen) & a single antigen can have many epitopes. also known ans Antigenic Determinants.
an immunogen are
antigens that can induce the formation of the immune cells/components. need to meet all requirements on list regarding size, foreignness, concentration, and shape # of epitopes.
Class II MHC on other types of cells may predispose to certain kinds of disease?
autoimmune diseases
Where do the cells congregate in specific immune system?
central lymphoid tissues/organs include bone marrow and thymus gland
chemical mediators of immunity include
complement system and cytokines
ABO system
consists of 2 major antigens: A & B Type A blood = type A antigens and type B antibodies Type B blood = type B antigens and type A antibodies Type O blood = neither A or B antigen
interferons fucntion?
defend body against tumor cell growth and viruses by inhibiting replication. Activates macrophages and NK cells.
macrophage
develop from monocytes that have migrated into tissues engulf and digest antigens and then present them on their MHC II molecules to T-Helper cells for immune system secrete cytokines like interleukin 1 and tumor necrosis factor
Rh system
either you have the antigen or you don't (+/-)
interleukins do what?
enhances response of lymphocytes and other cells to antigens and other foreign substances
antibodies structure is comprised of
heavy and a light chain variations in the constant region allow for classification of the antibody and for interactivity with cells/chemicals of the immune system the variable region allows for the antigen specificity and binding
list the types of t-lymphocytes
helper t cells suppressor t cells cytotoxic t cells memory t cells
Red blood cells dont have? do have?
human leukocyte antigen or MHC they have the ABO and the Rh systems to type blood
specific immunity can be broken into two types
humoral immunity: B-cell dependent, involve the production of antibodies, and is also known an antibody mediated cell mediated immunity - t cell dependent, involves cytokind mediation and is often initiated with APC cells
Cytokines include
interleukins, interferons, colony stimulation factors, and TNF
what are the primary cells of the immune system?
lymphocytes
antigen processing cells
macrophages, b cells, & dendritic cells
antigen presenting cells examples
macrophages, dendritic cells, b-lymphocytes, some activated T-cells and some epithelial cells
antibodies provide for (4 functions-
neutralization of bacterial toxins and viruses facilitate phagocytosis by opsonization complement activation/inducing inflammatory components like histamine and serotonin precipitation/agglutination of antigen/antibody complexes
do you need an antigen to provoke an immune response? what criteria must the antigen meet?
no the antigen must be large enough bigger than 10,000 daltons must be sufficiently foreign large enough for concentration to be recognized complex shape with multiple epitopes
primary response of immune system
occurs within 4-8 days of exposure to antigen IgM molecule can be detected if antigen is cleared and there is no more exposure, the antibody is broken down
how does the immune system recognize self from nonself?
our body have key self recognition molecules called Major Histocompatibility Complex Molecules (MHCs) and also called Human Leukocyte Antigen (HLA)
two examples of haptens
penicillin - 350 daltons that usually bind with body proteins to form larger complexes that are immunogenic. urushiol - in poison oak that works similarly
plasma cells do what?
produce antibodies that are specific to antigens are found in blood, secondary lymph organs, and some inflammatory sites
what do the B-cells do? (lymphocytes)
provide for elimination of bacterial invaders neutralization of bacterial toxins prevention of viral infection immediate allergic responses - immune response is initiated when antigen binds and interacts with receptors on surface of mature B cell - do this through antibody production
TNF
released by macrophages, induces apoptosis in certain cells like tumor cells, activates neutrophils and macrophages for inflammation, responsible for weight loss and cachexia seen in cancer and chronic inflammation
secondary response of immune system
second challenge by same antigen response is faster with rapid production of antibodies by memory cells IgG is predominant in this response.
characteristic of immune response
specificity - attack foreign cell by receptor diversity - ability to respond tp different antigens by many cells, more than one process memory - memory b and t cells, plasma cells for antibody generation self regulating - initiate, maintain, and turn off by suppressor cells discrimination of self and non self - clonal detection (tcells destroy self) clonal anergy - lack of activity ability to inactivate itself if they react to specific receptors for self-cells surveillance - natural killers
colony stimulating factors
stimulate the development of various blood cells or hematopoietic cells.
cell mediated immunity is mediated by
t-lymphocytes that develop in the thymus
what is immunity?
the body's ability to recognize materials that are foreign to itself and to neutralize, eliminate, or metabolize them without or without injury to its own tissue
antigens are usually? interact with?
these are large substances like large proteins usually, but can be polysaccaride molecules, nucleic acids and lipids as well. can include bacteria, fungi, viruses, protozoa, parasites, and non-microbial agents. They are foreign to us (the host) and can interact with the immune system.
therapeutic applications of immunity
vaccines immune serum globulin monoclonal antibodies cytokines
when is natural killer cells activity inhibitied? can be enhanced through?
when their cell surface comes in contact with MHC self molecules. can be enhanced with exposure to IL-2.
