Critical molecules involved in antigen presentation Tcell CD2 p56ick LFA-1 TCR CD28 L-1 CD4 IL-6 IFNy TNFa GM-CSF L-12 1L-4 L-15 TNFB ICAM-1 class ll LFA-3 B7-1/B7-2 APC (CD80/CD86)