Neoantigen Peptide Vaccine Plus Anti-CD38 Antibody Overcomes Immunotherapy Resistance in Cold Lung Tumors

From 2,536 missense mutations in the LLC1 lung cancer cell line, researchers identified 132 candidate neoantigen peptides, of which 25 induced CD8+ T cell responses. Short peptides failed to inhibit tumor growth as vaccines, but long peptide (L82)-pulsed dendritic cells delayed tumor growth in vivo. Combining L82-pulsed DC vaccination with anti-CD38 antibody effectively suppressed tumor growth by decreasing regulatory T cells in the tumor microenvironment, converting an immunotherapy-resistant cold tumor into one susceptible to immune rejection.

Whole-exome and RNA sequencing of the LLC1 cell line identified neoantigen candidates. 132 short peptides were screened for immunogenicity, and 25 induced CD8+ T cell responses. Dendritic cells were pulsed with long peptides and tested as vaccines in mice bearing LLC1 tumors. RNA-Seq identified high CD38 expression on tumor cells, leading to combination treatment with anti-CD38 antibody. Tumor growth, T cell responses, and tumor-infiltrating lymphocyte composition were assessed.

Roughly half of cancer patients don't respond to immunotherapy because their tumors are immunologically 'cold.' Finding ways to convert cold tumors into hot ones is one of the biggest challenges in oncology. This study demonstrates that a personalized neoantigen peptide vaccine combined with targeted antibody therapy can achieve this conversion, offering a potential strategy for treatment-resistant cancers.

Personalized cancer vaccines are a rapidly advancing field. This study shows that even immunotherapy-resistant tumors can be made vulnerable through the right combination of neoantigen peptide vaccines and antibody therapy. As sequencing costs drop and neoantigen prediction improves, approaches like this could become increasingly practical for patients who currently have no effective immunotherapy options.

This is a mouse study using a single lung cancer cell line (LLC1), limiting generalizability. Only one of the tested long peptides (L82) was effective as a vaccine. The approach requires tumor sequencing, neoantigen prediction, and combination therapy, making clinical implementation complex and expensive. Sample sizes for the animal experiments were not specified in the abstract.