Immunological Memory Flashcards
2 major goals of adaptive immune response
Control infection, remember pathogen
Immunologic memory
Property of remembering specific adaptive immune responses
2 factors contribute to defence by immunological memory
Circulating antibodies at low concentrations, ability to mount accelerated secondary response from memory cells.
Seasonal immunity
Antibodies produced during primary response prevent reinfection for months
Major differences between primary and secondary responses
Strength (affinity maturated) and speed (clone and proliferation of memory cells)
Components of imm. memory
Circulating Abs, T and B-memory cells.
Memory B cells are derived from which cells?
High affinity cells emerging from germinal center.
Short/long-lived plasma cells
Short are derived from low-affinity B-cell shortly after infections, long-lived are class-switched and high-affinity.
CD27
Expressed by memory B-cells
Long-lived plasma cell
Large, no surface Ig, isotype-switched.
Short-lived plasma cell
Large, no surface Ig, not class-switched.
Which cells are mainly responsible for high concentrations of antibody after primary response?
Short-lived plasma cells.
Ab life time
Last ca. 6 months.
Residual Ab levels
Are maintained by memory B-cells and long-lived plasma cells.
Homeostatic proliferation
Prol. in absence of external stimulation. Can be followed by diff. into long-lived plasma cells.
Reasons for faster and stronger secondary response
Higher precursoer frequency, optimal BCRs, more reactive.
FcγRIIB1
Inhibitory receptor expressed in naive B cells. Prevents activation of already known antigens by binding to Ab already bound on antigen.
With age the pool of memory B cells…
Becomes larger while the naive B cell pool becomes smaller.
Solution to HAN
Infusing mom with anti-Rh antibody.
Major feature of secondary B cell response
Inhibition of activation of naive B cells
How to discern between naive, effector and memory T cells
Protein expression
Memory T cell life time
Often entire lifespan
Maintenance of memory T cells
Homeostatic proliferation.
Reasons for stronger secondary T cell response
Outnumbers naive T-cells, more readily activated - less dependent on co-stimulation and more sensitive to cytokines.
Tcm
Central memory. Slower activation, may produce more effector cells.
Tem
Effector memory. Respond immediatly at sites of infection.
