Selection of Lymphocytes Flashcards Preview

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Flashcards in Selection of Lymphocytes Deck (12):
1

primary lymphoid organs

bone marrow, thymus

2

secondary lymphoid organs

spleen, lymph nodes, mucosal-associated lymphoid tissues

3

what results in self tolerance

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)

4

outer cortex of thymus

packed with immature T cells

5

inner medulla of thymus

place of maturation for T cells

6

MHC class I molecules

are expressed on all nucleated cells in the body including platelets

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

7

MHC class II molecules

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

peptide can stick out either end

8

positive selection

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

9

failure of positive selection

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

10

negative selection

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

11

two point checkpoint in t cell development

beta selection and positive/negative selection

12

alloreactivity

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