CD4 and infection: Although there was a transient change in the level of IgM+, CD4+CD8-CD25+, CD4+CD8+CD25+, and CD4-CD8+CD25+ lymphocyte subsets after PCV2 infection and LPC vaccination (data not shown), a profound pattern of statistical difference between groups 1 and 3 was clear after wild-type CSFV challenge (Figure 1).