CD4 and breast cancer: Consistent with this finding, Abx WT mice colonized with BC generated significantly higher populations of virus-specific CD8+ T cells both in the lung and spleen upon IAV PR8 infection (Figure 3(b) and Figure S3b), although the overall frequencies of bronchoalveolar lavage fluid (abbreviated as BALF hereafter) CD4+ and CD8+ T cells were comparable among the different groups (Figure S3c).