DICTIONARY

T-Cell Development

Positive selection: Is the selection of cells whose T-cell receptors respond to self-MHC. 

Negative selection: Is the selection against cells whose TCR react strongly to self-MHC combinations. 

Double Negative: This is when the fetal development of T-cell is TCR-independent and lacks the CD4+ and CD8+. So, the DN are CD4- & CD8-.  

Affinity Hypothesis: advanced model that is used to explain the paradox of MHC-dependent positive and negative selection. It asserts the differences in the strength of TC-mediated signals received by thymocytes undergoing the positive and negative selection indicating the result of the interaction. 

Intraepithelial lymphocytes: are mostly CD8+ cells that contain the features of the innate immune cells and patrol the mucosal surfaces. 

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