Most important antigen initiating graft rejection
the most important consequence of direct recognition is the activation of CD8+ T cells 
which recognise class I MHC molecules in the graft.Host CD4+ helper T cell may be triggered into proliferation and cytokine production by recognition of donor
class II MHC molecules  and drive an inflammatory response
MHC - molecule
Polysaccharide
DHA
HLA - Antigen