Blood Bank Unit 1: Adaptive Immunity T cell and B cell differentiation

what are the characteristics of adaptive immunity

• specificity

• memory

• enhanced response

• longer lasting

What are the two main branches in adaptive immunity

• cell-mediated immunity= t cells are the main component

• humoral immunity= b cells support antibody-mediated defense

what are immature T cells called

thymocytes

what do thymocytes lack

• they lack CD4 and CD8 markers on the surface

• they undergo rearrangement of gene coding for the beta chain of the t receptor

what is double negative?

when thymocytes lack CD4- and CD8- markers and start building the beta chain

what is the first part double positive stage

• when thymocytes now express CD4 and CD8

• double positive= both markers are

what is the second part of the double positive stage

• finish building the TCR

• it builds the a chain

what is the final step in double positive stage

• they test the TCR

• MHC has to be recognized appropriately

what is the single positive stage

• when the thymocyte only keeps one marker

• (SP= CD4+ OR CD8+— self reactive thymocytes— apoptosis/ sutvivors move towards maturity)

what are mature T cells

CD4+ t cells are t helper and t regulatory cells

• they will secrete cytokines and influence antibody production

CD8+ are cytotoxic t cells

• they kill target cells

where do t cells mature

in the thymus

where do b cells mature

in the bone marrow

what is a pro-b cell

• its gene rearrangement begins with the heavy chain

what is pre b cell

• heavy chain+ short ig a and ig b come together and from a pre -b receptor on the cell surface

what is an immature b cell

• they have a functional IgM BCR and they check for self antigens

• if the b cell is self reactive it will delete

mature b cells

• when immature b cells do not react with self antigen and display appropriate surface markets they migrate to the spleen for further development

what b cells to we get once they mature in spleen

• marginal b cells

• follicular b cells

what is a follicular b cell

• they migrate to lymph nodes and other secondary organs

what happens when antigen contact occures

• surface IgM/IgD provide an activating signal

• then b cells are stimulated and for memory and antibody secreting cells

what are plasma cells

• they make antibodies

what are T helper 2 cells

• help b cells produce antibodies

what do t regulatory cells do

• suppress the immune response to self antigens and harmless antigens

• they secrete inhibitory cytokinesis to inhibit proliferation of other t cell population

what do cytotoxic t cells do

• they destroy infected cells

• they are positive for CD8 marker

what is a t-dependent response

• can class switch from IgM to another antibody class

• memory cells are generated

• is a greater response

shat is a T independent response

• only IgM is produce

• memory is no produce