5. Principles of adaptive immunity

Question 1

what are the 4 basic principles of clonal expansion (for B and T cells)

Answer 1

1. each lymphocyte bears a single type of receptor with a unique specificity
2. interaction between a foreign molecule and lymphocyte receptor leads to lymphocyte activation
3. the differentiated effector cells derived from an activated lymphocyte bear identical receptors to those of the parental cell
4. lymphocytes bearing receptors for self-molecules are deleted early on and absent from the repertoire of mature lymphocytes

Question 2

central vs peripheral lymphoid organs examples

Answer 2

central = thymus and bone marrow
peripheral = lymph nodes, adenoids, tonsils, spleen, appendix, peyers patches

Question 3

central vs peripheral lymphoid organ function

Answer 3

central = where lymphocytes mature
peripheral = where lymphocytes congregate and interact with pathogens

Question 4

how are adaptive immune responses initiated by APCs in peripheral lymphoid tissues

Answer 4

dendritic cells in peripheral tissues migrate via lymphatic vessels to regional lymph nodes where they activate naive T cells

Question 5

where do specific leukocytes reside within a lymph node

Answer 5

B cells: primary lymphoid follicle and germinal centre (outside)
T cells: paracortical area (inside)
macrophages: medullary cords

Question 6

what are Peyers patches

Answer 6

specialized immune structures of the gut mucosa where pathogen recognition happens

Question 7

what are M cells

Answer 7

specialized cells on the surface of peyers patches which have membrane ruffles and help uptake antigens from the gut

Question 8

characteristics of adaptive immunity

Answer 8

based on specificity and diversity
recognize very specific foreign molecules
limitless in the diversity of molecules recognized
combat new and previously encountered pathogens

Question 9

cells of the adaptive immune system

Answer 9

T cells: develop in bone marrow, mature in thymus
B cells: develop and mature in bone marrow

Question 10

types of T cells

Answer 10

helper T cells (CD4): helps cytotoxic T cells and B cells in their immune function
cytotoxic T cells (CD8): kills virus infected and damaged cells

Question 11

types of B cells

Answer 11

memory B cells: create a robust response the second time an antigen is encountered
Plasma cells: produce antibodies

Question 12

humoral vs cell-mediated immunity

Answer 12

cell-mediated: controlled by T cells, when a pathogen is inside out cells
humoral: controlled by B cells, when an antigen is in our humors