The Effect of Bovine Herpesvirus Type 1 on Bovine Monocyte Derived Dendritic Cells

Dendritic cells (DC) are antigen presenting cells that provide an active surveillance system to monitor and present antigens to the immune system. DCs are very important for naive T cell activation and regulate both the innate and adaptive immune systems. Viral infection affecting DCs may adversely affect the immune system by hindering antigen presentation and/or T cell activation. In this study the effects of bovine herpesvirus 1 (BHV-1), a DNA virus, were evaluated based on DC viability, virus production and cell surface marker expression. Monocytes were differentiated into bovine monocyte-derived dendritic cells (MDDC) using bovine recombinant interleukin 4 (IL-4) and granulocyte-monocyte colony stimulating factor (GM-CSF). MDDCs were confirmed morphologically and phenotypically. Cooper and LA strains of BHV-1 were used in the study. The results revealed MDDCs could take up and produce infectious BHV-1. Infection accelerated MDDC death. An increase in viral titers and decrease in Ct values suggest that virus production increased from the time of infection until 48 hours post infection (p.i.), reaching Ct values of 31.89±3.90 and 31.21±3.48 and titers of 5.78±0.20 and 5.53±0.82 log10TCID50/ml for LA and Cooper respectively. Infection with BHV-1 did not significantly change the expression of MHCI, MHCII, CD86, CD14 or Dec205 on xiii the surface of MDDCs. The phenotype remained consistent with the cell control, showing no increase in CD86 and an increase in CD14, indicating BHV-1 did not alter the expression of cell surface markers. Although it has been shown that MDDCs can take up BHV-1, the downstream and in vivo effects of this infection are unknown. Further studies are needed to observe how additional strains of BHV1 modify MDDCs, along with effect of viral infection of MDDCs on T cell activation and cytokine production