Tumor-Induced Impairment of T-Cell-Independent B-Cell Blastogenesis and DNA Polymerase Activity 1

Abstract

Abstract

Fibrosarcoma-bearing BALB/c mouse spleens contained suppressor cells which inhibited B-cell blastogenesis and DNA polymerase activity. Two distinct populations of suppressor cells, macrophages (M⊘) and T cells, were capable of inhibiting lipopolysaccharide-induced B-cell DNA synthesis and DNA polymerase α activity. Direct suppression of B cells by M⊘ was a function of the in vitro concentration of M⊘ employed and inhibition was not mediated via soluble molecules. Suppressor T cells, however, regulated via soluble substances. The results from this study indicated that nonspecific suppressor cells of both the monocyte/M⊘ and T-cell lineage may affect T-cell-independent B-cell blastogenesis and ultimately regulate at the level of DNA replicative enzymes. However, M⊘ may have a minimal inhibitory role in tumor-burdened hosts, at least with respect to T-cell-independent systems.