Dental plaque deposits are known to be potent stimulants of lymphocyte transformation in patients with periodontal disease but not in normal subjects. Since plaque deposits consist mainly of whole bacteria, the cell walls of the most commonly found organisms in plaque were tested for their capacity to induce lymphocyte transformation. There was a direct correlation between the severity of peridontal disease and the amount of transformation induced by the cell walls of oral bacteria and by solubilized dental plaque. Cord blood leukocytes and lymphocytes from clinically normal people did not respond, which indicates that these stimulants are antigens rather than mitogens. Of the eleven bacteria tested, four members of the family Actinomycetaceae (Actinomyces viscosus, A. israelii, A. naeslundii, and Arachnia propionica), the related Propionibacterium acnes, and an anaerobic gram-negative anaerobic rod (27N). The high prevalence of the former organisms in the mature dental plaque that forms around the gingival crevice area and the potent efficacy with which they stimulate lymphocytes indicates that Actinomyces and certain gram-negative anaerobes may be important etiological agents in chronic periodontal inflammation in man.

No abstract

No abstract

5510 Nicholson, Kensington, Md.; and Miirine sarcoma virus ( M S V ) -induced transformed tumor cells, which are releasers and non-releasers of virus, were investigated by transplantation immunity and a variety of serological assays. Transplantation immunity demonstrated that tumor-associated transplantation antigens could be detected on producer cells and were also apparent, but to a lesser degree, on non-releaser cells of BALBjc mouse origin. Some lymphocyte inicrocytotoxicity tests employing hamster M S V tumors failed to detect any in vitro immunity. Studies employing immunofluorescence, complement fixation and virus .focus neutralization tests demonstrated that Harvey-MS V producer cells of hamster origin were strongly immunogenic in inducing antibody formation in syngeneic hamsters. By contrast, no antibody could usually be detected by these techniques following immunization with non-producer Harvey-MS V or immunization with either Moloney-MS V non-producer cells or those non-producer cells that had been made releasers by treatment with I U D R