Innate and adaptive immune responses of snatch-farrowed porcine-colostrum-deprived pigs to Mycoplasma hyopneumoniae vaccination

BACKGROUND The snatch-farrowed porcine-colostrum-deprived (SF-pCD) pig model, in which neonates are raised on commercially available bovine colostrum, is an alternative model for porcine infectious disease research. It is not known if SF-pCD pigs possess growth performance and immunity comparable to conventional, farm-raised pigs. The current experiment compared growth performance and immune responses of SF-pCD pigs to their farm-raised siblings following Mycoplasma hyopneumoniae (Mhyo) vaccination. Twelve SF-pCD and 13 farm-raised siblings were vaccinated on day 7 (D7) and D26 of age. Body weights were measured once or twice weekly and average daily gain (ADG) was calculated. Peripheral blood mononuclear cells (PBMC) were isolated on D40. Cytokine secretion from PBMC stimulated with Mhyo antigen or phorbol myristate acetate plus ionomycin (PMA/Iono) was assessed using a multiplexed fluorescent microsphere immunoassay (FMIA). Additionally, interferon gamma (IFNγ) secretion from stimulated PBMC was assessed using ELISPOT. Mhyo IgG titers were measured by an ELISA in D40 sera. RESULTS Growth performance did not differ between groups before weaning, but SF-pCD pigs had higher ADG after weaning. In response to Mhyo stimulation, numbers of IFNγ secreting PBMC and levels of interleukin 8 (IL8) and IL10 in PBMC supernatants were significantly higher in SF-pCD pigs, as were Mhyo antibody levels in sera, and levels of IL1β, IL8 and IL12 in supernatants of PMA/Iono stimulated PBMC. CONCLUSIONS Under the conditions of this experiment, SF-pCD pigs demonstrated superior growth performance and enhanced humoral and cell-mediated immunity following vaccination. Whether or not this reflects greater resistance or tolerance to infection is unknown but the ability to react positively to the vaccination provides evidence that SF-pCD pigs are a suitable alternative model for swine disease research.