CD79A and viral infectious disease: Notably, the antigen‐specific cells obtained from nasal mucosa were of the IgA subtype (Figure S2D, Supporting Information), known to play a critical role in the mucosal immune system against viral infection.[9] Additionally, antigen‐positive ratios in human bone marrow mononuclear cells (BMMC) were similar to those from mice, ranging from 37.5% to 89.2%.