immune response - 3rd line of defense
- vaccination - infecting harmless virus in order to improve resistance
- antigen - molecule provoking a specific immune response
- usually foreign to body
- antigenic determinant site - parts of antigen that stimulates an immune response
- antibodies - response to antigens
- created by B cells (made/mature in bone marrow)
- secreted into body fluid >> humoral immunity
- T cells (mature in thymus) directly attack the cells >> cell-mediated immunity
- exposed to pathogen, gaining immunity >> active immunity
- gaining antibodies from someone else >> passive immunity
starting the immune response - MHC proteins on cell surface
- proteins created y major histocompatibility complex
- serves as cellular fingerprint >> body can distinguish between its cells + foreign cells >> self-versus-nonself recognition
- antigen-presenting cells - partially digests microbes, moves their antigens to the surface
- lets T cells recognize the antigens
- MHC-I - found on all body cells
- MHC-II - found only on macrophages, B cells, and CD4+ T cells
- interleukin-1 - acts as chemical alarm signal between cells
T Cells - produces cell-mediated immune response
- protects body from infection, cancer
- helper T-cell - detects infection, initiates B/T cell responses
- cytotoxic T-cell - detect/kill infected cells
- inducer T-cell - helps T-cells mature in thymus
- suppressor T-cell - terminates immune response after infection
- cytokines - aka lymphokines
- regulatory molecules released by antigen-presenting cells
- interleukin-1 - released by macrophages, stimulates helper T cells promote macrophages
- interleukin-2 - released by helper T cells, stimulates production of cytotoxic T cells
- different MHC proteins >> higher chance for transplant rejection by immune system
- interferons currently used to stimulate immune system to fight cancer
B Cells - marks foreign microbe for destruction
- markers activate complement proteins, macrophages, natural killer cells
- binds to free, unprocessed antibodies
- trigger antibody production in plasma cells
- able to create million to billion different antibodies through somatic DNA rearrangement
antibodies - don’t directly destroy the cell
- IgM - 1st to be secreted during primary response, causes cells w/ antigens to stick together
- IgG - secreted in 2ndary response, major form of antibody in blood
- IgD - serves as receptors on B cell surface
- IgA - major form of antibody in saliva, milk (external secretions)
- IgE - promotes release of histamine to attack pathogen, responsible for allergies
- each consists of 2 light chains, 2 heavy chains
immunological tolerance - acceptance of a body’s own cells
- immune system in embryo originally responds to both foreign/self molecules
- autoimmune disease - when immunological tolerance fails
- B/T cells recognize their own tissue antigens
clonal selection - creates active immunity
- primary immune response - generally weak due to lack of B cells
- antigen binds to B cell >> cell division >> clones of B cells created
- 2ndary immune response - much stronger due to increase in recognition
Subject:
Subject X2:
