Role of autophagy in rejection after solid organ transplantation: A systematic review of the literature

Figure 1 The characteristics of different recognition ways in organ transplantation. Direct recognition: Recipient T cells directly recognize intact alloantigen peptide-major histocompatibility complex presented by the donor antigen presenting cell (APC) without antigen processing; Indirect recognition: Recipient T cells recognize the donor alloantigen-self major histocompatibility complex presented by recipient APC processing; Semi-direct recognition: Recipient T cells recognize intact donor alloantigen peptide-major histocompatibility complex on the surface of recipient APC that transferred from donor APC by exosome or other means. MHC: Major histocompatibility complex; APC: Antigen presenting cell; TCR: T-cell receptor; p-MHC: Peptide-major histocompatibility complex.