Pathogenesis of Bovine herpesvirus-1 (BHV-1) infections: Interactions of the virus with peripheral bovine blood cellular components

Bovine herpesvirus-1 (BHV-1) is believed to reach the placenta via the hematogenous route as the virus has been recovered from the blood buffy coat cells of experimentally infected cattle. However, the manner in which the virus relates to these and other blood cells while in transit in the blood is not known. The nature of this relationship was investigated in the present study.

An in vitro correlate of the in vivo cell-virus interactions was simulated by isolating peripheral blood cells on a Ficoll-Hypaque gradient and testing their capacity to adsorb and act as host cells for BHV-1 replication. It was shown that all leukocytes, but not red cells, can adsorb virus readily. Of the leukocytic fraction, monocytes and lymphocytes adsorb the virus most effectively. Monocytes supported viral replication while lymphocytes could do so only after stimulation with phytohemagglutinin.

It is concluded that in vivo replicating BHV-1 is transported in monocytes, and is adsorbed to all leukocytes from which it finally reaches the placenta, leading to abortion.