T Cell Development

 

 

TCRs become expressed following gene rearrangement, producing double positive (CD4+, CD8+ cells). Mature cells, either CD4+ or CD8+, develop in the thymus. It is unclear how this choice is made, although it is possible that MHC I or II recognition is an important part of this .

Negative selection also occurs in order to prevent self-reactivity.

 

Unlike B cells, which can recognize antigen alone, TCR can recognize antigen only when presented in an MHC class II molecule.