Flow Cytofluorimetric Analysis of Lymphocyte Subset Alterations in Cattle Infected with Bovine Viral Diarrhea Virus

Abstract

Clinically normal, bovine viral diarrhea virus (BVDV)-seronegative, 7 to 9-month-old steers were inoculated intranasally with NY-1, a noncytopathic strain of BVDV, or exposed intramuscularly to killed BVDV. Indirect immunofluorescence staining with monoclonal antibodies specific for bovine leukocyte subsets followed by flow cytometric analysis was used to monitor subsequent hematologic alterations. Infection with BVDV resulted in a transient leukopenia which was characterized by decreases in the absolute numbers of circulating T lymphocytes, including BoT4+ ("helper") and BoT8+ ("cytotoxic/suppressor") subsets, B lymphocytes, and neutrophils. There was no significant variation in numbers of non-T, non-B ("null") lymphocytes or monocytes. Exposure to inactivated BVDV in a combination vaccine did not cause significant alteration in the circulating numbers of any major leukocyte subset; however, significant variation was seen in the BoT4/BoT8 ratios and in the numbers of cells expressing major histocompatibility complex (MHC) class II antigens.

Experimental inoculation of calves with laboratory strains of bovine viral diarrhea virus

“…(P < 0.001, P < 0.05 and P < 0.01 respectively). Bolin et al and Ellis et al showed that BVDV caused a decrease in the absolute numbers of B and T lymphocytes and in the percentage of T lymphocytes along with a decrease in the number of neutrophils [26,27]. The typical course of the clinical picture, e.g.…”

Clinical response and immunomodulation following experimental challenge of calves with type 2 noncytopathogenic bovine viral diarrhea virus

“…After staining, cell samples were fixed in 0.4 mL 0.4% formaldehyde in phosphate buffered saline solution (pH 7.2) prior to analysis with a flow cytometer (FACScan, Becton Dickinson, San Jose, California, USA). The results were expressed as the percentages of PBMCs (10 6 ) expressing at their surface either B7, B4, MHC I or MHC II molecules [10,17].…”

Infectious Agents

“…121,127 Of the T-lymphocyte subpopulations, CD8 + cytotoxic T-lymphocytes are most dramatically depleted, followed by CD4 + T-helper cells, with little reduction of circulating γ/δ T-cells. 128 In addition to lymphocyte depletion, functional alterations of CD4 + cells are pronounced, and noncytopathic BVDV infections result in a shift toward the Th2 response, with reduced cell-mediated but high levels of humoral immunity. [129][130][131] Virulent BVDV isolates can cause reductions in MHCI expression of infected cells, thus affecting cytotoxic CD8 + cell function; however, this reduction appears to be strain-dependent.…”