Bovine γδ T cell response in foot-and-mouth disease virus infection (FMDV) (81.12)

Abstract

Abstract In cattle, ?d T cells are a major population of the peripheral blood T cells but there is no precise description of their role in viral infections. We examined the phenotype and function of bovine ?d T cells during infection with FMDV. The early phase of infection was examined to test for a possible role for ?d T cells in innate responses against FMDV. Gamma delta T cells were sorted from PBMC of naïve or FMDV infected Holstein calves. The cells from naive animals highly expressed CD62 and CD45RO and about 50% expressed CD25, but not CD335. Gamma delta T cells did not produce IFNγ and no lytic activity could be demonstrated against a tumor cell target in vitro, although a very low level of perforin was detected. Cells from infected animals had phenotypic alterations on γd T cells between 2 and 6 days post infection (dpi). Expression of CD62 and CD45RO was down regulated and CD25 expression moderately increased. Unexpectedly, CD13 was expressed on days 2 and 3 after infection and were cytolytic against K562 cells. In addition, γδ cells isolated on these days expressed CD335, perforin and produced IFNγ. However, the isolated γd T cells produced less IFNγ and expressed less perforin compared to γd T cells assayed from non-sorted PBMC, indicating that the function of γd T cells may depend on factors derived from other cells. Overall, bovine γd T cells are activated upon infection with FMDV and adopt NK cell phenotypical and functional properties. Therefore, bovine γd T cells may likely participate in the innate response to infection with FMDV and targeting activation of γδ T cells could lead to rapid protection against FMDV infection.