describe the 3 signals involved in the activation and differentiation of naive t cells
It is generally assumed that the activation of naïve T helper (Th) cells is the result of a two-cell interaction between the Th cell and a dendritic cell (DC) and that three signals are required.
Signal one or stimulation is the recognition by the T-cell receptor (TCR) of antigenic peptides presented by major histocompatibility complex (MHC) class II molecules. Or we can say that it is antigen-specific, and interacts with peptide MHC molecule on the membrane of antigen-presenting cells(APC).
Signal two or co-stimulation is mainly provided by the triggering of CD28 on the T cell by CD80 and CD86 molecules on the DC.
Signal three or polarization directs T-cell differentiation into various effector phenotypes such as Th1 and Th2.
Lymphocyte differentiation is a process in which activated B cells or T cells become specialized immune cells.
T-cell differentiation is the act of T helper cells (Th) becoming regulatory T cells, or Tregs, and preventing unchecked Th17 immune responses. This occurs partly through the production of the short-chain fatty acids (SCFAs), butyrate, propionate, and acetate, which are the by-products of fiber fermentation by microbes in the colon.
describe the 3 signals involved in the activation and differentiation of naive t cells