Nonadherent spleen cell populations exposed in vitro to ribonucleic acid-rich preparations from mouse macrophages that had been incubated with human γ-globulin (RNA : HGG) were able to produce specific antibody, as measured by rosette-forming cells, in lethally irradiated (800 R), reconstituted, syngeneic mice. Exposure of the RNA to anti-HGG serum abrogated its ability to initiate antibody synthesis, as did monospecific anti-human γ chain and anti-human κ chain serum. Normal rabbit serum, anti-bovine albumin serum, anti-human μ chain or anti-human λ chain serum, when substituted for anti-HGG serum had no effect. Thus, the presence of both γ heavy chains and κ light chains of the antigen in the RNA moiety was indicated. Although both an adherent and a nonadherent cell were required by HGG to stimulate rosetteforming cells in irradiated mice, the need for the adherent cell was eliminated when RNA : HGG was substituted for HGG. In addition, anti-θ-treated bone marrow cells exposed to the RNA : HGG were capable of rosette-cell formation, suggesting that RNA attachment converted a T cell-dependent antigen to a T cell-independent antigen.
Bibliographical noteFunding Information:
2 Supported by Ford Foundation Advanced-Study Fellowship. Taken in part from a dissertation submitted to the Graduate School, The University of Michigan, Ann Arbor, Mich., in partial fulfillment of the requirements for the Doctor of Philosophy degree. Present address: Department of Microbiology, Howard University Medical School, Washington, D.C. 20059. s Abbreviations used in this paper : PEC, peritoneal exudate cells; BSA, bovine serum albumin; HGG, human y-globulin; BME, Eagle’s basal medium; HBSS, Hanks’ balanced salt solution; RFC, rosette-forming cells; PFC, plaque-forming cells, SRBC, sheep red blood cells; NASC, nonadherent spleen cell; ASC, adherent spleen cell; NRS, normal rabbit serum; n-RNA, RNA extracted from normal macrophages; RNA: HGG, RNA extracted from macrophages sensitized to HGG; PBS, phosphate-buffered saline.
1 This research was supported by U.S. Public Health Service Grant No. AM 14273. Presented in part to the 75th Annual Meeting of the American Society of Microbiologists, New York, N.Y., May 1975.