The purpose of this study was to determine the environmental effects on porcine innate immunity and the related changes of methylation patterns for TRL genes. Naturally farrowed/artificially raised piglets (12) were split into 2 groups at weaning. One group was orally exposed (E) to a nonpathogenic inoculum 1x daily over 1 week. The second group was left un-exposed (UE). Four weeks after the oral exposure was completed, pigs were experimentally infected with M. hyopneumoniae. During the study, group E had significantly reduced respiratory clinical signs that included coughing and lung lesions, and seroconverted earlier than group UE, suggesting a beneficial effect of the oral non-pathogenic inoculation on the severity of mycoplasmal pneumonia. Monocytes and neutrophils were isolated from blood samples weekly for the duration of the study. Bisulfite sequencing was performed for the CpG Island of TLR-1. No significant difference in the methylation pattern of TLR-1 was detected. Expression level experiments on TLR-2 and 6 in the lung were performed. These TLRs are responsible for the recognition of M. hyopneumoniae in pigs. The results showed higher levels of expression in group UE compared to group E, with a fold change of 1.96 and 1.76 for TLR-2 and 6, respectively. Further experimentation in order to determine if these changes reflect differences in the methylation patterns of the CpG Islands of TLR-2 and 6 are underway.
This project was conducted using funding from USDA Grant numbers 538 AG 2009-34480-19875, 2008-35205-18769, and 538 AG58-5438-7-317l.