Table 2.
Innate and pro-inflammatory cytokine levels quantitated by ELISA in the sera of 10-day-old gnotobiotic pigs inoculated with the IPEC-J2 cell culture-passaged PDCoV (OH-FD22-P8-I-P4) or mock at post-inoculation day 1.
| Group |
Pig no. |
Clinical signs |
Innatea |
Pro-inflammatorya |
|||
|---|---|---|---|---|---|---|---|
| IFNα (pg/ml) (fold increase) | IL-22 (pg/ml) (fold increase) | TNFα (pg/ml) (fold increase) | IL-6 (pg/ml) (fold increase) | IL-12 (pg/ml) (fold increase) | |||
| PDCoV-inoculated | 1 | Watery diarrhea | 332b (190-fold) | 446 (112-fold) | 18 (4-fold) | 622 (4-fold) | 78 (4-fold) |
| 2 | Watery diarrhea | 682 (390-fold) | 133 (33-fold) | 18 (4-fold) | 542 (3-fold) | 68 (3-fold) | |
| Mock-inoculated | 3 | None | 1 | 4 | 4 | 222 | 28 |
| 4 | None | 1 | 4 | 4 | 175 | 22 | |
| 5 | None | 2 | 4 | 5 | 105 | 13 | |
| 6 | None | 3 | 4 | 4 | 138 | 17 | |
| Mean (SD)c | 2 (1) | 4 (0) | 4 (1) | 160 (50) | 20 (6) | ||
The samples were tested in duplicate, and cytokine levels were expressed as the mean values. Detection limits of our ELISA were 1 pg/ml for IFNα and IL-12, 4 pg/ml for TNFα and IL-22, and 16 pg/ml for IL-6, respectively.
Bold numbers, trends toward increased innate (IFNα and IL-22) and pro-inflammatory (TNFα, IL-6, and IL-12) cytokine levels in sera of PDCoV-infected pigs and the fold increases compared with the mean values of the cytokines tested in the four mock-inoculated pigs 3–6.
Although statistical analysis was not done due to too few animals in the infected group, the data clearly indicate that infected Gn pigs exhibited pronounced systemic innate and to a lesser extent, pro-inflammatory cytokine responses to acute PDCoV infection.