Listeria ivanovii upregulate expression of OvCD₄ and OvCD₈ T-cell antigens in naturally infected ewes

Four naturally infected ewes with Listeria ivanovii were investigated to examine the proportions of T lymphocyte subpopulation in peripheral blood. The levels of lymphocyte subpopulation were analysed in cytosmears of peripheral blood mononuclear cells by enzyme immuno-assay employing OvCD₄, OvCD₈ and OvCD₅ specific monoclonals. Infected ewes had significantly increased proportions of both OvCD₄⁺ and OvCD₈⁺ T lymphocytes than uninfected ewes of the same age (P<0.005). However, the proportion of OvCD₅⁺ T lymphocytes were not significantly different from that of uninfected ewes. The ratio of OvCD₄⁺ and OvCD₈⁺ T lymphocytes remained at low ebb during the infection.