What are lymphocytes? (3 types)
a type of leukocyte
- Natural killer cells
- T cells
- B cells
Natural killer cells have a what immunity
innate immunity
T cells have what immunity
cell mediated immunity
B cells have what immunity
humoral immunity
humoral means blood B for blood cells
What do NK cells function as?
- protect against viral infections and some cancers
- fast
What are the 3 roles of NK cells on targets?
- cell to cell contact DESTROY
- release interferons (IFN) and cytokines to WARN other cells
- release IFN an cytokines to ENHANCE immune response of other cells
What does a APC do in response to an antigen?
- encounters antigen
- engulfs
- processes
- presents antigen with the MHC II antigen on the cell surface
What does the T cell recognize?
- recognizes the antigen presented on the APC (antigen presenting cell) in association with MHCII
MHC class II cells are found mostly on what types of cells?
- B cells
- dendritic cells
- macrophages
How do helper T cells respond to if it encounters a target?
- CD4 (helper T cell) encounters foreign antigen fragment on MHC on APC
- helper T cells secrete cytokines to enhance immune response
Where does the initial priming of helper T cell lymophocytes occur?
prime to antigen in lymph tissues (spleen lymph nodes tonsils, gut)
How are antibodies made and memory cells made with the help of helper T cells?
- helper T cells, activated by APC
- activated helper T binds B cell
- B cell proliferates and differentiates
- memory cell (for innante immunity)
- antibody production
MHCII is to helper T cells as MHCI is to ____
cytotoxic T cells
Difference between MHCII and MHCI
- MHCII are on macrophages, B cells, and dendritic cells
- MHCI are on all nucleated cells
MHCII - helper T cells
MHCI - recognized by cytotoxic T cells
What does cytotoxic T cell (CD8) do?
encounters foreign antigen on MHC
- recognize
- T cell activated
- effector cytotoxic T will target and kill it
- while memory cells are created from proliferation of activated cytotoxic T
How do cytotoxic T cells actually “kill” other cells?
- activated
- release perforin
- forms pores (perforin channels)
- release granzymes through perforin channels
- granzymes set off apoptosis
- activate FAS death receptor
What is the clonal selection theory?
at birth there are lots of B cells
- each Bcell produces on type of antigen but naive until exposure to antigen to stimulate clonal division
Humoral B cell immunity phase one
Primary Phase: clonal expansion
- some short lived effector - produce antibodies
- other memory continue to reproduce
Humoral B cell immunity phase two
Secondary Phase: memory cells
- only memory cells persists
- when reexposed to antigen (appropriate one)
- memory cells rapidly expand and produce more effector and memory cells (divide again)
What do the effector cells of B lymphocytes immunity produce?
- produce antibodies!
Explain the B Lymphocyte response in regards to speed and strength of response
Primary 1st exposure to antigen - slower - weaker - produce IgM (memory) antibodies Secondary - lymphocyte clones and memory cells - faster - stronger IgG antibodies
Allergies are abnormal response of B cells
- immediate hypersensitivity
- eliciting IgE Ab instead of IgG Ab
Allergies are abnormal response of T cells
- delayed hypersensitivity
- reaction mediated by lymphokines not Ab
