The mechanism of the immunosuppressive effect of staphylococcal peptidoglycan (PG) on the primary antibody (Ab) response to sheep erythrocytes in mice was studied. The immunosuppression could be transferred into normal recipients by syngeneic spleen cells from PG-treated mice, while transfer of spleen cell sonicates was not effective. In vitro immunization of dispersed spleen cell cultures revealed that anti-erythrocyte response of splenocytes from PG-treated mice was substantially lower than the Ab response of splenocytes from untreated animals. Ten to 20% of spleen cells from PG injected mice suppressed the Ab response of normal splenocytes when added at the initiation of the cultures. Living cells were required for the effective suppression, and PG-induced suppressor cells interfered with the early stage of the immune response. Cell fractionation revealed that nonadherent spleen cells from PG-treated mice were not immunosuppressive for normal cells. Adherent cells from PG-injected animals were immunosuppressive at very low concentrations (2%). At higher concentrations (20%) adherent cells from untreated mice were also immunosuppressive. The adherent cell population comprised 90% macrophages. These cells could be made immunosuppressive by in vitro treatment with PG. This suggested direct induction of immunosuppressive cells by PG.
|Original language||English (US)|
|Number of pages||9|
|Journal||RES Journal of the Reticuloendothelial Society|
|State||Published - Dec 1 1979|
ASJC Scopus subject areas