To characterize the phenotype of CD8/10.4 and CD4/10.4 T cells, cells isolated from the lungs during infection were stimulated in vitro with TB10.4 74–88 and TB10.4 3–11 and analyzed by flow cytometry for expression of CD4, CD8, CD44, CD11a and IFN-γ. This evidence concerns the gene IFNG and infection.