Changes in the absolute number of IgM+ (A), CD4-CD8+CD25+ (B), CD4+CD8-CD25+ (C), and CD4+CD8+CD25+ (D) lymphocyte subsets in various treatment groups of pigs after classical swine fever virus (CSFV) challenged over time as determined by flow cytometry. The pigs in group 1 (PCV2-infected/LPC-vaccinated/CSFV-challenged) and group 2 (PCV2-infected/CSFV-challenged) were inoculated with porcine circovirus type 2 (PCV2) at 0 dpi. The pigs in group 1 and group 3 (LPC-vaccinated/CSFV-challenged) were vaccinated with 1 dose of Lapinized Philippines Coronel (LPC) vaccine at 12 dpi. The pigs in all four groups were inoculated with wild-type CSFV (ALD strain) at 27 dpi. Data are shown as mean ± SD. a-dValues with different superscripts indicate that the differences among groups are statistically significant (P < 0.05).