The silent enemy: possible role of Bovine leukemia virus in mastitis incidence in cattle.

MARTINEZ CUESTA, LUCIA; CERIANI, MARIA CAROLINA; SHEAHAN, MAUREEN A; ROWLAND, RAYMOND RR

Manhatan, Kansas

Jornada; Phi Zeta Research Day; 2019

Society of Phi Zeta Sigma College of Veterinary, Kansas State University

Bovine leukemia virus (BLV) is a retrovirus that affects cattle causing a lymphoproliferative disease. Previous studies suggest that BLV infected animals could have a greater incidence of mastitis. The aim of this study was to stably infect a bovine mammary epithelial cell line (MAC-T) with BLV and analyze the effect of the virus in the epithelial response to S. aureus and E. coli, bacteria responsible of mastitis. The infection with BLV was confirmed by nested PCR, qPCR, immunocytochemistry, western blot and transmission electron microscopy. MAC-T and MAC-T BLV cells were incubated for 6 h with a heat-inactivated suspension of S. aureus or E. coli. Viability was analyzed by the MTT method and gene expression analysis was done by Real-time PCR. The results showed a decrease in BLV infected cells viability when exposed to S. aureus and E. coli, compared to the uninfected counterpart. After 6 h of incubation with S. aureus, MAC-T BLV cells express 0.24 times less Toll like receptor 2 (TLR2) than MAC-T cells (p= 0.0428). TLR2 is a pleiotropic receptor that plays an important role in the recognition of pathogens that enter the lumen of the mammary gland. The decrease in this receptor expression and in the epithelial mammary cells viability could favor the development of mastitis in BLV infected cattle. Our data support the conclusion that BLV can stably infect bovine epithelial mammary cell and provides additional information supporting the hypothesis that BLV infected cattle may have a greater incidence of mastitis.