Lymphocytes Flashcards
what are the cells of the innate response
macrophages, NK cells, monocytes, neutrophils, dendritic cells and complement
how are genes involved in resistance to pathogens developed for the adaptive immune system
VDJ recombination (not inherited)
what are the secreted products that mediate the innate immune response
complement, lysozyme, CRP, defensins
what are the HLA loci associated with MHC1?
MCH2?
MHC1= HLA-A, HLA-B, and HLA-C MHC2= HLA-DR, HLA-DP, HLA-DQ
what does MHC2 bind?
MHC2 binds CD4 and TCR
where is MCH1 expressed?
expressed on all nucleated cells (not RBC’s)
where is MHC2 expressed?
expressed on all APC’s
how are antigens transported to the surface of the cell for recognition after endogenous processing
beta2 microglobulin carries the antigen to the surface
how are antigens loaded in MHC2-containing cells
after invariant chain is released in an acidified endosome the antigen is loaded
what condition is associated with HLA subtype A3
hemochromatosis
what condition is associated with HLA subtype B27
Psoriatic arthritis, Ankylosing spondylitis, IBD, Reactive arthritis (formerly Reiter’s)
what condition is associated with HLA subtype DQ2/DQ8
Celiac’s disease
what condition is associated with HLA subtype DR2
multiple sclerosis, hay fever, SLE, Goodpasture’s syndrome
what conditions are associated with HLA subtype DR3
diabetes mellitus type 1, SLE, Grave’s disease
what conditions are associated with HLA subtype DR4
rheumatoid arthritis, diabetes mellitus type 1
what conditions are associated with HLA subtype DR5
pernicious anemia (which leads to B12 deficiency), Hashimoto’s thyroiditis
what two enzymes do NK cells use to induce apoptosis of infected and tumor cells
granzyme and perforin
what cytokines promote NK cell activity
IL-2, IL-12, IFN-alpha and IFN-beta
NK cells will be triggered to kill a cell if it’s missing a certain surface protein. What protein is this?
MHC1
what receptor / surface protein binds the Fc portion of Ig to activate NK cells
CD16
what’s the difference between how CD4+ cells and CD8+ cells defend against pathogens
CD8+ cells kill directly, CD4+ cells make cytokines to trigger other immune players and they also promote B cells to produce antibodies
where does positive selection for T cells occur and how
cortex of the thymus; T cells with TCRs that recognize MHC survive
where does negative selection for T cells occur and how
medulla of the thymus; T cells that bind with high affinity to self-antigens undergo apoptosis
name the three kinds of antigen presenting cells
B cells, macrophages, dendritic cells
what are the two signals for naive T cell activation
signal 1= foreign antigen is presented to T cell (either CD4+ or CD8+)
signal 2=costimulation by binding of CD28 on the T cell to B7 on the APC
what are the two signals for B cell activation and class switching and what event (which isn’t technically one of the signals
signal 1= B cell endocytoces and presents antigen on MHC to Th cell via its TCR signal 2=CD40 on B cell binds CD40L on Th cell -->then the Th cell secretes cytokines that induce the B cell to undergo maturation, class switching and antibody production
what cytokines do Th1 cells secrete
IFN-gamma
what cytokines do Th2 cells secrete
IL-4, 5, 6, and 13
what do Th1 cells do
activate cytotoxic lymphocytes and macrophages
what do Th2 cells do
they activate eosinophils and promote IgE production
what cytokines inhibit Th1
IL-4 and IL-10 from Th2 cells
what cytokines inhibit Th2
IFN-gamma
what cytokine produced by macrophages induces differentiation to Th1 cells
IL-12
what kinds of cells do cytotoxic T cells kill
infected, tumor, and donor graft cells
what is granulysin
an antimicrobial molecule secreted by cytotoxic T cells to induce apoptosis
what cell surface markers do regulatory T cells have
CD3, CD4, CD25
what transcription factor is characteristic of regulatory T cells
FOXP3
what cytokines do activated T regs produce
IL-10 and TGF-beta
what does the Fc portions of IgM and IgG do
fix complement
which terminal of the protein is the Fc portion
C terminal
what kind of recombination does the light chain do
VJ recombination
what three main functions do antibodies have
complement activation, opsonization, neutralization
what two kinds of Ig do mature B cells have on their surfaces
IgM and IgD
how do cells producing IgM start producing other kinds of antibodies
isotype switching (triggered by T cell activation via CD40L)
what’s the most abundant Ig isotype in serum
IgG
what functions does IgG serve
opsonization, crosses placenta, fixes complement, opsonization of bacteria and neutralization of bacterial toxins and virus
where is IgA most abundant and what does it do
mucous membranes; prevents attachment of pathogens to membranes; gets secreted (as a dimer) into saliva, tears, mucus, and breastmilk
what does IgE do
binds mast cells and basophils leading to release of granules; cross-links when exposed to allergen in order to promote type I hypersensitivity rxn; triggers eosinophils to respond to parasites
