Identification of guinea pig γδ T cells and characterization during pulmonary tuberculosis

Guinea pigs are an alternative small animal model for many disease studies. Here we describe a pan-γδ monoclonal antibody (anti-TCRδ1) specific for the constant region of human T cell receptor delta chains that cross-reacts with a subpopulation of guinea pig (Cavia porcellus) lymphocytes. The phenotype and distribution of this subpopulation is consistent with the guinea pig γδ T cell subset. FACS analysis of fresh PBMC and splenocytes from naïve guinea pigs revealed the presence of a subset of cells that stained with the anti-TCRδ1 mAb. The relative percentage of anti-TCRδ1 positive cells in PBMC and tissues is similar to that described for γδ T cells in other species. Immunohistochemistry of tissues also revealed a distribution of anti-TCRδ1 positive cells consistent with γδ T cells. These data are further supported by staining of a polyclonal guinea pig T cell line that became progressively CD4 and CD8 negative in long-term culture. Analysis of PBMC from guinea pigs following aerosol infection with virulent Mycobacterium tuberculosis revealed no apparent changes in the steady-state percentage of blood γδ+ T cells. Taken together, these data suggest that the anti-TCRδ1 antibody recognizes the γδ T cell subset in guinea pigs. This reagent may be useful for examining γδ T cells in various disease models where the guinea pig is a more desirable model for study.