Sixteen crossbred barrows (Duroc × Landrace × Yorkshire) weaned at 28 days with an initial body weight of 5.12-8.64 kg and no antibodies to PCV2 were used in a 5-week trial to evaluate the immune response after intranasal inoculation with type-2 porcine circovirus. The percentage of peripheral blood ANAE+ T cells, PCV2 antibody titer, immunoglobulins, and serum IFN-g, IL-2, and sIL-2R levels were determined. The results show that the percentage of peripheral blood ANAE+ T cells was notably higher in inoculated pigs 5 days post-inoculation (dpi) and significantly lower 21 dpi than in the control group. The anti-PCV2 titer in the inoculated group was significantly higher than that in the control group 14 dpi. The immunoglobulin profile of the 2 groups also differed. The IFN-g level in the inoculated group decreased significantly from 7 to 28 dpi, as compared with the control group. The results suggest that PCV2 challenge results in an immune system response.

Sixteen crossbred barrows (Duroc × Landrace × Yorkshire) weaned at 28 days with an initial body weight of 5.12-8.64 kg and no antibodies to PCV2 were used in a 5-week trial to evaluate the immune response after intranasal inoculation with type-2 porcine circovirus. The percentage of peripheral blood ANAE+ T cells, PCV2 antibody titer, immunoglobulins, and serum IFN-g, IL-2, and sIL-2R levels were determined. The results show that the percentage of peripheral blood ANAE+ T cells was notably higher in inoculated pigs 5 days post-inoculation (dpi) and significantly lower 21 dpi than in the control group. The anti-PCV2 titer in the inoculated group was significantly higher than that in the control group 14 dpi. The immunoglobulin profile of the 2 groups also differed. The IFN-g level in the inoculated group decreased significantly from 7 to 28 dpi, as compared with the control group. The results suggest that PCV2 challenge results in an immune system response.