Tumor-associated antigen P1A (P1A) (P1A)

The P1A tumor antigen, encoded by the Trap1a gene, is a prototypical cancer-germline antigen (CGA) originally identified in the murine P815 mastocytoma (Van den Eynde et al., 1991, Science). It is characterized by a highly restricted expression pattern, being present in various malignant tissues and normal germ cells of the testis and placenta, but absent from healthy adult somatic tissues (Lethe et al., 1992, Eur J Immunol). This expression profile makes P1A a significant model target for cancer immunotherapy, as it allows for the induction of tumor-specific immune responses with minimal risk of systemic autoimmunity. In preclinical research, P1A has been targeted using various strategies, including recombinant viral vector vaccines (e.g., MVA-P1A) and adoptive T-cell therapies utilizing P1A-specific T-cell receptors (TCRs) (Rosato et al., 2001, Vaccine). These therapeutic approaches function by stimulating CD8+ cytotoxic T lymphocytes to recognize the P1A-derived peptide (LPYLGWLVF) presented by the H-2Ld MHC class I molecule. While P1A is highly immunogenic, its effectiveness as a target can be limited by mechanisms of immune evasion, such as the downregulation of MHC molecules or the emergence of antigen-loss variants (Shrikant et al., 1999, J Exp Med). Furthermore, the study of P1A has provided foundational insights into the mechanisms of peripheral tolerance and the role of costimulatory molecules in anti-tumor immunity. As a non-mutated self-antigen, it serves as a critical tool for understanding how the immune system can be trained to overcome tolerance to cancer-testis antigens.

Other names

Tumor rejection antigen P1ATrap1aP815 tumor antigenP1A tumor antigen

Induction of antigen-specific cytotoxic T lymphocyte (CTL) responses against tumor cells expressing the P1A peptide-MHC complex.