Specific Defense Mechanisms
Antibody Classes
1. IgA 2. IgM 3. IgD 4. IgE 5. IgG
Components of Immune System
1. Thymus 2. Bone Marrow 3. Lymph nodes 4. Lymphatics 5. Spleen
Allergen
Antigen which provoke an allergic response (IgE)
Epitopes
Antigenic determinants Specific regions of an antigen to which Antibody reacts
Immunogens
Antigens which evoke an antibody response (other than IgE)
Antibodies
Globulin proteins produced in response to an antigen
Duality of the Immune System
Humoral and cell mediated responses
Tc/CD8+
T cells are cytotoxic, need to be activated by helpers to attack. Active cells are CTLs. They attack target cells by releasing perforin and granzymes. Granzymes induce apoptosis on target cells.
Th/CD4+
T cells mediate communication, activate B cells to produce antibody, activate cytotoxic cells
Macrophages
act as APCs. Present T cells
Memory Populations
after stimulation, B cells and T cells produce memory cell populations
IgE
allergic response Location: Bound to mast & basophil cells throughout body, blood Function: Allergic reactions
Haptens
antigens w/molecular weights, not antigenic by themselves. They must be attached to a larger antigen
Natural Killer cells
attack parasites, tumor cells and virally infected cells. Do not need to be stimulated by antigen. They attack cells which do not express MHCI antigens
Cytokines
chemical mediators of up and down regulation of the immune system
Lymph Nodes
contain fixed macrophages which clear infection site of immune reactions
Spleen
contains lymphocytes/macrophages; immune response
interleukins
cytokines that serve as communicators between leukocytes
Chemokines
cytokines which induce migrations of leukocytes into areas of infection
Major Histocompatibility Antigens I
expressed on all nucleated cells of the body
Antigen
foreign substance which evokes an immune response. Have molecular weights higher than 10,000
IgD
function largely unknown Location: B cell surface, blood, lymph Function: Not known
IgA
membrane bound antibody, is a dimer Located: Secretions (tears, saliva) blood, lymph Function: Localized protection on mucosal surfaces
Major Histocompatibility Antigens II
only expressed on antigen presenting cells (macrophages, B cells)
IgM
pentamer, first antibody produced in response to exposure, 3-5 days Location: Blood, Lymph, B cell surface Function: Especially effective against microorganisms
B cells
produce antibody, act as antigen presenting cells (APCs)
Thymus
site of maturation for T lymphocytes
Bone marrow
site of production of lymphocytes; B cells mature here
IgG
very specific response to antigens, produced after IgM Located: blood, lymph, intestine Function: Enhances Phagocytosis, neutralizes toxins & viruses Protects fetus
Lymphatics
vessels containing lymph (fluid)
