Effect of classical swine fever virus infection on the T lymphocyte subpopulations in peripheral blood and changes of alpha-interferon and gamma-interferon of pigs

To elucidate the effects of classical swine fever virus(CSFV) low virulent strain Thiverval(T) and virulent strain GXW-07(G) infection on immune cells,kinetics of CD4+ and CD8+ T lymphocyte subpopulations and peripheral blood leukocytes apoptosis of pigs infected experimentally with CSFV were analyzed by flow cytometry.The results showed that CD4+ T lymphocyte subpopulations in pigs inoculated with T or G strain was significantly decreased form 33.4% to 26% and 36.8 % to 20%,and CD8+ T lymphocyte subpopulations was declined from 43.8% to 32% and 48.8% to 25% at 7 days post-infection(pi),respectively.Counts of leukocyte apoptosis in peripheral blood of the infected pigs were significantly more than those of the control pigs,the IFN-γ secretion was lower than control pigs.On the contrary,the TNF-α secretion was higher than control pigs.Indicating that apoptosis induced by CSFV infection might be the cause of leucopenia and immune suppression.