Activation of murine B cell lymphomas. I. Influence of lipopolysaccharide
Lanier, L.L.
Journal of Immunology 129(3): 1130-1137
1982
ISSN/ISBN: 0022-1767 PMID: 6980920 Document Number: 189543
The influence of lipopolysaccharide [LPS] on pre-B and B lymphoma cell lines was investigated. Tumor cells were examined for alterations in cellular proliferation, Ig secretion and cell surface phenotype after culture in the presence of 50 .mu.g/ml LPS for 24 and 48 h. Striking changes in surface differentiation antigen expresion on the L10A/2J and NBL-DU-B cell lines were observed. Culture in the presence of LPS consistently resulted in a 2.5- to 3-fold increase in the amount of surface I-Ad and I-E/Cd determinants on the L10A/2J cell line, without changing the quantity of H-2Kd or H-Dd gene products. LPS activation of NBL cells caused a 4- to 5-fold increase in the quantity of surface IgM and ThB antigens, without significantly increasing the amounts of the cell surface differentiation antigens or inducing a switch in surface Ig isotype or Ig secretion. This preferential increase in quantity of surface antigen on these lines was not simply related to increase in cell size (surface area) after LPS activation, but rather it reflected actual increase in cell surface density of these determinants. Furthermore, the change appeared unrelated to cell cycle regulation. A detailed kinetic analysis of the activation process is presented. These phenotypic changes were noted over a wide range of LPS concentrations (1-100 .mu.g/ml), and occurred within 4 h after cells were cultured in the presence of LPS. Removal of the LPS resulted in the loss of the phenotypic changes within 72 h, demonstrating that this process required the continuous presence of the inducing agent and is a reversible event. LPS alone can induce significant phenotypic changes in cloned transformed cell lines of the B lineage. A model system for delineating the specific events associated with LPS activation is provided.