In vitro stimulation and maintenance of bovine herpesvirus-1 (BHV-1) primed bovine T-lymphocytes

Bovine herpesvirus-1 (BHV-1), an important viral pathogen of cattle, causes severe respiratory infection, conjunctivitis, abortion, vulvovaginitis, balanoposthitis and systemic infection. To study the role of CD₄⁺, CD₈⁺ and γ/δ T-lymphocytes in BHV-1 infection and immune-pathogenesis, the peripheral blood mononuclear cells (PBMCs) were isolated from seropositive calves and cultured in vitro in presence of inactivated BHV-1 or glycoprotein-C (gC). The PBMCs, unstimulated (at 0 day) and stimulated (at 9^th day post-stimulation), were probed with monoclonal antibodies against bovine CD₄⁺, CD₈⁺, CD₄₅R and γ/δ T-lymphocytes using indirect fluorescent antibody test. The CD₄⁺ and CD₈⁺ cells were increased in PBMCs isolated from seropositive calves after in vitro stimulation with BHV-1 or gC antigen. Similarly, γ/δ T-lymphocytes were also maintained after culturing with both the antigens. In control seronegative calves, number of these T-lymphocytes was low after stimulation with either BHV-1 or gC. This indicates that during BHV-1 infection CD₄⁺, CD₈⁺ and γ/δ T-lymphocytes are maintained and play role in immune-pathogenesis.