CD4 and infection: However, compared to CD8 T cells, antigen specific CD4 cells were more polyfunctional, recruited at a higher rate, and proliferated more following infection with M.tb, indicating that although both CD4 and CD8 epitopes are clearly presented at the very onset of infection, CD4 and CD8 T cells respond very differently to live infection, in a manner which support the consensus that CD4 T cells play the major role during the early stages of an M.tb infection.