Inhibition of In Vitro Friend Murine Leukemia Virus Infection of Lipopolysaccharide-Activated B-Cells With Concanavalin A<xref ref-type="fn" rid="FN2">2</xref>

Abstract

Stimulation with bacterial lipopolysaccharide (LPS) of splenic B-lymphocytes infected in vitro with Friend virus complex increased the number of cells with replicating murine leukemia virus (MuLV) [i.e., infectious centers (IC)] up to 100-fold. Concanavalin A (Con A) did not have such an effect. However, the addition of Con A to the LPS-stimulated cultures decreased the number of IC. The inhibitory concentration of Con A (2.5 microgram/ml) was eightfold less than that capable of neutralizing the in vitro infectivity of MuLV (20 microgram/ml). The effect of Con A was not mediated by T-cells; the inhibition of infection was comparable with use of whole spleen cell suspensions from normal BALB/c mice, with T-cell-depleted cell suspensions, or with spleen cells with congenitally athymic nude mice. However, specific removal of Con A from the surface of B-cells with alpha-methyl-D-mannopyranoside prior to the infection reversed the inhibitory effect entirely. It is suggested that the lectin interferes with MuLV on the membrane of B-cells.