The Immune Response

Question 1

differences between primary and secondary response

Answer 1

• shorter lag time
• higher rates of antibody synthesis
• higher peak of antibody titer
• longer persistence of antibody
• predominance of IgG molecules
• higher affinity of antibody
• requires less antigen

Question 2

b cells

Answer 2

• express surface immunoglobulin
• single variable region-idiotype
• total pop makes repetoire
• proliferate with T cell help
• clonal expansion and then class switch (plamsa cells)/ memory cells
• inc in affinity due to selection for the antibodies that bind the best

Question 3

helper T cell

Answer 3

• CD4
• recognize different set of antigens
• T cells recognize the protein carrier molecule while B cells can recognize both (hapten + carrier)
• react with antigen on surface of presenting cell and co stim factors
• proliferate and stimulate B cells
• daughter B cells respond to Tcell derived factors
• other factors responsible for class switch

Question 4

T independent immunogens

Answer 4

• polymeric molecules having a large number of repeating subunits that cause cross linking of Ig on B cell
• polyclonal activators of V cells that provide mitogeic signal that would have been provided by T cells
• Toll receptors

Question 5

antigen presenting cells

Answer 5

• initiate interaction with antigen by endo/phagocytosis
• may be enhanced by complement, preexisting antibody, or with specific receptors
• uptake, processing, presentation
• antigen is presented by cells that bear our MHC antigen
• co stim-CD28:B7 T cell has CD, APC has B7

Question 6

APC must

Answer 6

1. take up and process antigen
2. have MHC class II
3. present antigen and MHC class II
4. Have co stim B7
   - B cells can do this too