Selection of Lymphocytes

Question 1

primary lymphoid organs

Answer 1

bone marrow, thymus

Question 2

secondary lymphoid organs

Answer 2

spleen, lymph nodes, mucosal-associated lymphoid tissues

Question 3

what results in self tolerance

Answer 3

cells whose idiotype has too great an affinity for normal cellular molecules are deleted (clonal deletion) in the bone marrow or inactivated in periphery (clonal anergy)

Question 4

outer cortex of thymus

Answer 4

packed with immature T cells

Question 5

inner medulla of thymus

Answer 5

place of maturation for T cells

Question 6

MHC class I molecules

Answer 6

are expressed on all nucleated cells in the body including platelets

closed at both ends, peptide cannot stick out, peptide contained within binding groove

Question 7

MHC class II molecules

Answer 7

are expressed on antigen presenting cells (macrophages, B lymphocytes, dendritic cells, Langerhans cells)

peptide can stick out either end

Question 8

positive selection

Answer 8

developing t cells that bind with low affinity are given signal to divide and establish clones that will mature in medulla

Question 9

failure of positive selection

Answer 9

developing t cells that fail to recognize self-MHC are not encouraged to mature

Question 10

negative selection

Answer 10

developing t cells that bind too strongly to self MHC molecules will be induced to undergo apoptosis

eliminates autoreactive cells whose receptors bind too strongly to a self peptide, self MHC complex

Question 11

two point checkpoint in t cell development

Answer 11

beta selection and positive/negative selection

Question 12

alloreactivity

Answer 12

alloresponse, what happens when you transplant MHC molecules from someone else, occurs with transplant tissues, can have interactions with someone else’s MHC based only on MHC or with peptide only