SRA

This study was undertaken to obtain a global view of the temporal changes in equine immune gene expression between from the neonatal stage to adulthood. To this end, transcriptome analysis of peripheral blood mononuclear cells (PBMCs) from foals on the day of birth and again 6 weeks later was performed and contrasted with those of adult PBMCs. Differential gene expression analysis identified 2,280 genes with =2 fold change between PBMCs sampled on day 1 and 42 (p=0.01). Approximately 1,000 genes differed between either day 1 or day 42 PBMC and adult PBMC. Progressive increases in expression of genes involved in adaptive and cell-mediated immunity were documented between days 1, 42, and adulthood. New insights of natural killer cell-specific genes were obtained, many of which increased expression levels between days 1 and 42 (p=0.0005), when adult levels were achieved. Transcriptome data also demonstrated the profile of T cell receptor delta (TCRD) transcripts, representative of gamma delta T cells, which peaked in day 42 PBMCs (p=0.0136) although TCRD expression was equivalent between day 1 and adult PBMCs (p>0.05). Transcriptome data further revealed several aspects that may impair robust immune responses in the neonatal period. TLR3 gene expression was lowest in day 1 PBMC (p<0.0001) and this may contribute to viral susceptibility. Increased expression of IL27, IL13RA1, IREM-1, LAIR-1, SIRL-1, and SIRPalpha was observed in day 1 PBMC (p=0.0198) compared to day 42 PBMC; these immunosuppressive molecules may dampen immune responses in early life. These results provide insight to the unique attributes of the equine neonatal and young immune system, and offer many avenues of future investigation. Overall design: Peripheral blood mononuclear cell mRNA profiles of foals on day 1 of life, day 42 of life, and adult mares (n=4 per group) were obtained by sequencing Illumina TruSeq Stranded mRNA Libraries on an Illumina NextSeq500.