Frameshift-derived neoantigen-specific T-lymphocyte response (FSNA-specific T-cell response)

Frameshift-derived neoantigen-specific T-lymphocyte response refers to the targeted activation of the adaptive immune system against novel protein sequences produced by frameshift mutations in cancer cells. These mutations, typically insertions or deletions in microsatellite regions, result in "non-self" peptides that are highly immunogenic because they have not been subjected to central immune tolerance (Mandal et al., 2019, Science). This response is a primary driver of the clinical efficacy observed with immune checkpoint inhibitors in patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) tumors (Le et al., 2017, Science). Therapeutic strategies such as the Nous-209 vaccine are designed to proactively stimulate this response by delivering shared frameshift neoantigens to prime T-cell activity (D'Alise et al., 2022, Science Translational Medicine). Because these neoantigens are absent from healthy tissue, the resulting T-lymphocyte response offers a high degree of tumor specificity and a favorable safety profile compared to traditional therapies. However, challenges remain, including potential tumor escape through the loss of antigen presentation machinery or the development of an immunosuppressive tumor microenvironment.

Other names

Frameshift neoantigen-specific T-cell responseFSNA-targeted immune responseNeoantigen-specific T-lymphocyte activationMutation-derived neoantigen response

Induction and expansion of CD8+ cytotoxic and CD4+ helper T-lymphocytes that specifically recognize novel, non-self peptide sequences generated by frameshift mutations and presented on MHC molecules, leading to targeted tumor cell lysis (Mandal et al., 2019, Science).