Polyclonal activation of B-lymphocytes in vivo by Salmonella typhimurium lipoprotein.

Lipoprotein prepared from the outer membrane of Salmonella typhimurium is a polyclonal activator of murine B-lymphocytes. It was shown to be mitogenic for splenic cultures, stimulating increased incorporation of [3H]thymidine into DNA. When injected intravenously into mice, the lipoprotein induced splenomegaly and polyclonal B-cell activation. The latter was evident from an increase in the number of plaque-forming cells against trinitrophenylated sheep erythrocytes. Similar results were obtained with Escherichia coli lipoprotein.