Role of monocytes in polyclonal immunoglobulin production stimulated by sonicates of periodontally associated bacteria

Abstract

These studies were initiated to investigate monocyte regulation of polyclonal antibody responses of human peripheral blood lymphocytes stimulated by sonicates of periodontally associated bacteria. With pokeweed mitogen (PWM) as a positive reference, the role of monocytes in the peripheral blood lymphocyte response to Streptococcus sanguis and Wolinella HVS was examined by manipulating the number of monocytes and lymphocytes in culture. In comparison to PWM, optimal responses to the bacterial sonicates required very few monocytes (0.3% of the total cultured cells). Restoration of monocytes to physiological levels resulted in suppression of the response. PWM-stimulated responses were optimal at 5 to 15% monocyte content and were abolished after monocyte depletion. Individuals who were low responders or nonresponders to bacterial sonicates responded at normal levels after manipulation of monocyte concentration. Nonresponders produced normal levels of antibody when the monocyte concentration was reduced to 0.3% but were inhibited after monocyte reconstitution. The effects of monocyte concentration were tested over a wide dose range of bacterial sonicate and found to conform to the observed pattern throughout the dose range tested (10 to 1,000 micrograms/ml). The contrasting monocyte requirement of peripheral blood lymphocytes stimulated with PWM versus bacterial sonicates may reflect a quantitative difference in optimal macrophage concentration or may be due to a qualitative difference in lymphocyte-monocyte interactions in response to these activators.

Monocyte suppression of Fusobacterium nucleatum-induced human polyclonal B-lymphocyte activation

“…The mechanism(s) by which monocytes suppress F. nucleatum-PBA is not known. The suppression was not due to a cytotoxic effect of the isolated monocytes on the lymphocytes, since the monocytes were able to concomitantly restore PWM-PBA in a dose-dependent fashion, as previously reported by other investigators (7,12,18,28). In addition, the monocyte suppression did not reflect an inhibitory increase in cell density in the cultures for the following reasons: (i) lymphocytes were added to the cultures in suboptimal concentrations so that the addition of monocytes would yield a more optimal cell density for F. nucleatum-PBA (23); (ii) control cultures containing equivalent numbers of monocyte-depleted lymphocytes were not suppressed;…”

“…Suppressor monocytes are associated with a number of diseases, such as systemic lupus erythematosus (19), sarcoidosis (16), multiple myeloma (6), tuberculosis (9, 17), and fungal diseases (31). As reported in a recent study by Carpenter et al (7) and in a previous study from our laboratory (22), the removal of adherent cells from unfractionated cell populations is necessary to obtain PEA responses to other microorganisms associated with periodontal diseases. In contrast, pokeweed mitogen (PWM)induced PBA (PWM-PBA) is optimal when monocytes are present in moderate concentrations (5 to 30%) and is abrogated by thorough monocyte depletion (<4%) or when excess (>30%) monocytes are present in lymphocyte cultures (10,18,29).…”

Relationship between gingival crevicular fluid and serum antibody titers in young adults with generalized and localized periodontitis

“…The radioimmunoassay for total IgG has been described previously (5). HSA was assayed by using the same method.…”

Isolation of Wolinella recta and Actinomyces viscosus from an actinomycotic chest wall mass

“…Penicillin is the drug of choice for actinomycosis and is also effective against W. recta. Studies of the pathogenic potential of W. recta have only recently begun (2).…”