lecture 3 Flashcards
(69 cards)
Adaptive immunity
Cell mediated (t-cells)
antibody mediated (b cells)
5 thing of adaptive immunity
- Discrimination (responds selectively to non-self)
- Specificity (activated T or B cells respond to specific non-self antigens)
- Diversity (generates cell receptors & antibodies)
- Tming (turned on after activation by innate response)
- Memory (response to a second exposure is so rapid that there is usually no noticeable illness)
Humoral immunity
- Antibody mediated
- B cells circulate antibodies that bind microorganisms, toxins, and extracellular viruses to neutralize them or destroy them
Cellular immunity
- T lymphocytes
- CTL (cytotoxic T cells) directly target cells infected with intracellular pathogens
- T helper cells– direct CTL to target cell lysis
antigen
self or non-self substance that elicits an immune response
Epitopes
antigenic determinant sites, site where antigen binds to antibody
Valence
of antigenic determinant sites on the surface of antigen
Antibody affinity
strength which an antibody binds to its antigen
haptens
small molecules that become immunogenic when combined with a carrier protein
Naturally acquired active immunity
immune systemc ome sin contact w antigen such as a pathogen causes an infection
Naturally acquired passive immunity
transfer of antibodies from mother to child
Artificially acquired active immunity
Vaccines
Artificially acquired passive immunity
antibodies or lymphocytes produced by one host are introduced into another
MHC
(major histocompatibility complex)
collection of genes encoding proteins that enable the host to distinguish between self and non-self
Human leukocyte antigen (HLA)
location of Human MHC on chromosome 6
- 3 classes
1. Class 1- found on cell w nucleus
2. Class 2 - appear on cells that can process antigens and present them to T lymphocytes
3. Class 3 - irrelevant
Class 1 MHC
Identify all healthy nucleated cells in the body as self
- stimulate immune response when cells from host are introduced to another host
- basis for tissue typing for organ transplant
Class 2 MHC
- produced only by dendritic cells, activated macrophages, mature B cells, and some innate lymphocyte cells (ILCs)
- key to adaptive immunity
- bind large non-self peptides
Antigen processing
mechanism of how peptides bind to MHC molecules
Class 1 MHC antigen processing
bind peptides by sampling the proteins in the cytoplasm of all nucleated cells
Endogenous antigen processing
only peptides that fit perfectly within the binding spot of MCH 1 are binded
Exogenous antigen processing
foreign particles that have been taken up by phagocytosis can be bound to MHC class 2 molecules
Antigen-presenting cells (APCs)
immune cells that place non-self antigen on MHC class 2 molecules
B cells
produce and secrete antibodies
T cells
initiate, orchestrate, and carry out an adaptive immune response