Prostatic acid phosphatase-derived peptide–MHC complex (PAP-MHC complex)

The Prostatic acid phosphatase-derived peptide–MHC complex is a molecular assembly consisting of a peptide fragment from the prostatic acid phosphatase (PAP) protein bound to a Major Histocompatibility Complex (MHC) molecule (UniProt P15309). PAP is an enzyme highly expressed in both normal and malignant prostate tissue, making it an ideal target for prostate cancer immunotherapy (Kantoff et al., 2010, NEJM). These complexes are presented on the surface of antigen-presenting cells (APCs) or tumor cells and are specifically recognized by T-cell receptors (TCRs) on the surface of T lymphocytes. This recognition is the fundamental step in the activation of an adaptive immune response against prostate cancer cells (McNeel et al., 2009, JCO). Therapeutic strategies, most notably the FDA-approved cellular immunotherapy Sipuleucel-T, utilize this mechanism by loading APCs with PAP-related antigens to stimulate the production of PAP-specific T cells (FDA, 2010). Once activated, these T cells circulate and identify the PAP-MHC complexes on the surface of prostate cancer cells, triggering targeted cell death.

Other names

PAP peptide-HLA complexProstatic acid phosphatase antigenACPP-derived peptide-MHC complexPAP-MHC

Induction of a T-cell mediated immune response where antigen-presenting cells display PAP-derived peptides on MHC molecules to activate specific T-cell receptors, leading to the lysis of PAP-expressing tumor cells (Kantoff et al., 2010, NEJM).