Zapnometinib treatment and influenza A virus infection modulate the HLA class I ligandome in human lung adenocarcinoma cells

IntroductionInfluenza viruses continue to pose a global health threat, and available antiviral therapies are limited by resistance and reduced efficacy. Host-directed drugs such as MEK inhibitors have emerged as promising alternatives.

Zapnometinib, a clinical-stage MEK inhibitor, has shown both antiviral and immunomodulatory activity. However, its impact on antigen presentation at the level of the HLA-I ligandome has not been investigated.MethodsLabel-free LC–MS/MS was applied to analyze HLA-I–presented peptides in human lung adenocarcinoma Calu-3 cells.

Cells were infected with Influenza A virus (IAV) H3N2/Fukui and treated with zapnometinib. Surface HLA-I expression was quantified by flow cytometry, and immunopeptidomic analyses were applied to assess ligandome alterations and functional pathway enrichment.ResultsZapnometinib treatment and IAV infection did not significantly alter HLA-I surface expression (fold changes 1.01-1.13, p > 0.05).

Immunopeptidomics revealed allotype-specific changes in the relative abundance of HLA-I-presented peptides (approximately 3–12% change per allotype), and statistically significant modulation of defined ligand subsets (about 3–14% of ligands per condition; log2 fold change ≥ 2, adjusted p < 0.05).