B cells that carry the complement receptor (CR+) were separated from B cells that lack the complement receptor (CR-) by velocity sedimentation or by passage through C-coated Sephadex columns. The kinetics of responses to bacterial lipopolysaccharide (LPS) in both B cell subpopulations were determined in three assay procedures: 1) incorporation of radioactive thymidine into DNA; 2) incorporation of radioactive leucine into immunoglobulin; 3) enumeration of cells forming polyclonal antibody to the 2,4,6-trinitrophenyl hapten.

Although both subpopulations of B cells responded to LPS, they differed in the time course. CR- B cells responded with a delay of approximately 24 hr as compared with the response of CR+ B cells. The implications to the ontogenetic status of CR+ and CR- B subpopulations are discussed.


This work was supported in part by National Cancer Institute Grants CA 08748, CA 16889, and CA 17085.

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