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43 Cards in this Set
- Front
- Back
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Specific immunity |
Against the target micro is the third line of defense. It is acquired or developed over time |
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Antigens |
Foreign molecules that trigger immunity. Epitopes are they actually recognized part |
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Epitopes |
Antigenic determinant, small parts antigens |
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Effective antigens |
Usually large molecules Protein and glycoprotein( nucleic acids are less effective) complex molecules |
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Haptens |
Tiny molecules that become antigens when bound to larger molecules |
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Types of antigens |
Auto Exogenous -truly foreign indigenous endogenous -within infected cells Autoantigens- self recognized as foreign normally self tolerance is formed during development antigens- self recognized as foreign normally self tolerance is formed during development |
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Lymph |
Colorless watery liquid no pump, only flows toward the heart |
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MALT |
Appendix, Lymphoid tissue of respiratory tract Peyer's patches and small intestine |
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B lymphocytes |
Found in spleen lymph nodes red bone marrow and peyer's patches Only few circulate Major function secrete antibodies (immunoglobulins) |
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Antibodies |
4 peptide chains 2 heavy 2 light Linked by disulfide bonds Stem called the Fc region ( lower portion of heavy chains) Two variable regions, 1 heavy chain 1 light form the antigen binding site (Fab region fragment antigen binding) |
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Five types of heavy chains |
IgG IgA IgM IgE IgD |
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Antigen binding sites, once bound.. |
Complement activated inflammation triggered agglutination neutralization opsonization |
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Agglutination |
(Clumping) Because each antibody has two binding sites multiple antigens can be bound increasing chance of phagocytosis |
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Neutralization |
Blocks the "active" site of a toxin or interferes with attachment of a microbe |
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Opsonization |
Enhanced phagocytosis multiple antibodies can be bound to an antigen. All Fc regions are exposed. These trigger phagocytosis by neutrophils |
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IgG |
85% of serum antibodies Complement activation agglutination opsonization and neutralization
Leave the blood vessels easily because of small size Can cross placenta Very important in inflammation early responded to microbes |
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IgM |
2nd most common 5 x larger than IgG Forms pentamer
Very efficient at complement activation virus neutralization and agglutination |
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IgA |
Associated with secretions tears and milk 5% monomers in serum plasma cells and mucous membranes tear ducts memory ducts makeup monomers and form dimers using a secretory component (secretory IgA) which promotes secretions and protects against antibody breakdown Agglutination and neutralization Prevents gastrointestinal respiratory urinary and reproductive infections Antibody associated with breastfeeding benefits Monomer Less than 1% of serum antibody concentration act as signal molecules Attached to basophils and mast cell receptors causing histamine release and inflammation Most important role in allergy and parasitic worm infections |
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IgD |
Monomer Not secreted Membrane-bound NOT found in all mammals |
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B cell receptors |
Not all antibodies are secreted from B cells Mini integrate into the cytoplasmic membrane of B cells and are called BCR Not formed in response to antigens B cells respond to antigens in directly |
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T cells |
TCR are also present on T cells and are randomly generated TCR has 2 polypeptide chains in the middle is the antigen binding site - form the cell mediated response b/c because they respond directly to antigens - represent 90% of the lymphocytes in the blood |
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Four types of T cells |
- cytotoxic (Tc): have cd8 receptor and directly kill other cells (virally infected or cancer cells) - type 1 helper(TH1): assist Tc cells & secrete cytokines -type 2 helper (TH2): assist B cells & secrete cytokines -Suppressor T cells |
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Cytokines (messenger proteins) |
- Interleukins (ILs): signal leukocytes IL1-IL27 -Interferons (IFNs): Gamma IFN stimulates TH1 cells & has antiviral activity -Growth factors: stimmulate stem cells to ÷. -Tumor necrosis factors (TNFs): kill tumor cells. Regulates immune response & inflammation |
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Chemokines |
Attract white blood cells to signs of inflammation or infection |
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MHC |
Major histocompatibility complex Group of antigens found in the surface of animal cell membranes -called HLA in humans MHC proteins identify cells as self Hold foreign antigens and present the antigen to T and B cells |
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Class I MHC |
Found on the membrane of all nucleated cells |
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Class II MHC |
Is only on B cells and special antigen presenting cells (APCs) such as monocytes, macrophages and dendritic cells in lymphoid organs and on skin surfaces |
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T- independent antigens |
large repetitive antigens |
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T dependent antigens |
Describes most antigens which are not large |
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exogenous antigens |
Apc's phagocytize microbes chops them up into small fragments( antigenic determinants) on the surface along with MHC II. |
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Endogenous antigens |
Those from intracellular bacteria or viruses are fragmented and presented on the surface with MHCI. The MHCI comes from the ER and they get transported together to the surface of the Golgi |
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Memory B cells |
Small percentage of B cells. Have BCRs Stay in lymphoid tissue Memory B cells which are already sensitized to an antigen respond quickly to another challenge by that antigen. They differentiate without meeting an antigen presenting cell. These new B cells produce massive surge of antibody. secondary response is faster and more effective |
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Cell mediated immunity |
Used for intracellular pathogens and abnormal body cells |
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Killing- 2 ways |
1. Perforin-granzyme pathway 2. CD 95 pathway |
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Perforin-granzyme pathway |
Tc cells have to set of toxins in their cytoplasm -Perforin Forms hollow tube which creates Channel and infected cells membrane -granzymes Move through perforin Channel and activate apoptotic enzyme. Cell commits suicide but Tc is NOT destroyed it can give Kiss of Death to several cells |
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CD95 |
A membrane glycoprotein found in most human cells. CD95L receptor is presented to Tc cells. When the two blind apoptosis is triggered |
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Memory T-cells |
Small percentage of T cells Persist for months or years Found in lymphoid tissue Secondary response of these cells does not require a PC. The secondary response (memory response) is more effective |
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T Cell regulation |
When T cells and APCs (immunological synapse), the specificity involved ensures that T cells are not activated unintentionally |
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types of acquired immunity |
Natural or artificial Active or passive |
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Naturally acquired active immunity |
Infection by cold or virus |
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Naturally acquired passive immunity |
IgG crossing the placenta into a fetus IgA in breast milk |
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Artificially acquired active immunity |
Killed vaccines |
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Artificially acquired passive immunity |
Antibody harvested from another animal (antitoxins or antisera) and injected into a patient |
