GAMMA-DELTA T-CELLS PRESENT ANTIGEN TO CD4(-BETA T-CELLS() ALPHA)

gamma delta and alpha beta TCR+ T cells share many properties and thei r interactions are likely to be coordinated and regulated. We provide evidence that cattle gamma delta T cells are able to present antigen t o CD4(+) T cells. To help elucidate their function gamma delta T cell Lines were propagated for extensive characterization. Cells expressed high levels of MHC class II and production of co-stimulatory molecules as evidenced by the binding of a CTLA-4 fusion protein and synthesis of CD80 transcripts. These properties and the presence of a well-devel oped endosomal compartment indicated the cells might function as antig en-presenting cells. Resting CD4(+) T cells from calves immunized with ovalbumin or respiratory syncytial virus-antigen proliferated in resp onse to gamma delta T cells pulsed with antigen that appeared to be en docytosed via clathrin-coated pits or specific receptors.