Journal of Leukocyte Biology 43:256-264 (1988) © 1988 Alan R. Liss, inc. Flow Cytometric Analysis of Porcine Peripheral Blood Leukocytes Infected With Pseudorabies Virus

The susceptIbilIty of fractionated porcine peripheral blood ieukocytes (PBL) to pseudo-rabies virus (PRV) was studied by flow cytometry and defined by viral antigen expres-sion. Viral antigens on the surface of Infected cells and cell viability were evaluated by forward angie light scatter (FALS), 90-degree light scatter (9OLS), green fiuorescence (FITC-antl-PRV), and red fluorescence (propidium Iodide). Approximately 10 % of in-fected mononuclear cells from healthy pigs expressed cell-surface PRV antigen. Cell-surface fluorescence and cell type were confirmed by sorting live positIve cells for microscopy. In sorted positive sampies, the lymphocyte versus monocyte ratio was approximately 50%:50%, defined by morphology. Positive lymphocytes represent 5.75% of total mononuclear cells. When cells were stimulated with phytohemagglutlnin (PHA) and llpopolysaccharide (LPS) before Infection, mitogen-stlmulated T-lymphoblasts showed increased susceptibility to PRV (40.7 % positive) and died of infection. Mono-cytes, particularly adherent monocytes, were highly susceptibie (40 % to 71.4 % p051-tive). Granulocytes appeared to be refractory. The relative susceptibility of various PBL populations was compared by normalizing lymphocyte susceptibility to 1 as follows: resting total lymphocytes (1); B-iymphocytes (0.67); T-lymphoblasts (7.08); total mono-cytes (4.27); adherent cells (4.03 to 10.88); adherent monocytes (6.95 to 12.42); granu. locytes (0.24). These findings suggest a possible mechanism by which PRV could have an immunosuppressive effect as well as a pathway for disseminatIon of PRy