Number and distribution of T lymphocytes in the small intestinal mucosa of calves inoculated with rotavirus

Abstract

An understanding of the immune response to rotavirus is needed to develop effective prophylaxis. There is evidence that cell-mediated responses may be involved and to extend these observations, rotavirus antigen and the three major T cell subsets, BoCD4 ⁺, BoCD8 ⁺, and BoWC1 ⁺ γ/ δ lymphocytes were immunostained in tissue sections from calves killed at 2, 4, 6, 8 and 10 days post inoculation and quantified by image analysis. It was established that in control calves, BoCD4 ⁺ lymphocytes were predominantly in the lamina propria, while the majority of BoCD8 ⁺ and BoWC1 ⁺ γ/ δ lymphocytes were in the epithelium. Rotavirus infection was seen throughout the small intestine with the greatest amount of viral antigen detected at 4 days post inoculation in the mid and distal small intestine. Increased numbers of all subsets were detected; small increases in intraepithelial BoCD4 ⁺ and BoWC1 ⁺ γ/ δ T lymphocytes were observed especially in the distal small intestine, while larger increases in BoCD8 ⁺ cells were detected in the epithelium and lamina propria of the proximal, mid and distal small intestine. The timing and location of these increases in T lymphocyte subsets is indicative of a specific immune response involving BoCD8 ⁺ and BoWC1 ⁺ γ/ δ T lymphocytes.