CD4 and infection: In the present study, differences were noted in the percentages of CD4+CD8α+ T cell and IgM+ B cell subpopulations in the spleen of turkeys in response to the challenge (C. perfringens vs. LPS); infection with C. perfringens led to a greater increase in the percentage of CD4+CD8α+ T cell subpopulations than the administration of LPS, whereas the opposite was observed in IgM+ B cells.