Reversal of murine alveolar macrophage-mediated suppression of plaque-forming cell response by sodium periodate.

Murine alveolar macrophages (AM) have been shown to suppress the in vitro plaque-forming cell (PFC) response of spleen cells previously primed with sheep erythrocytes (SRBC) in a dose-dependent manner. Mild oxidation of cell membranes on viable AM with sodium periodate resulted in total abrogation of AM-mediated suppression of the PFC response, while periodate treatment of spleen cells resulted only in partial reduction of the suppression. Pretreatment of AM with sodium periodate followed by addition of the aldehyde blocking agent, hydroxylamine, resulted in restoration of the PFC-suppressing activity of AM. Periodate treatment of AM also resulted in significantly increased macrophage-T-cell binding and cluster formation. These observations suggest that the generation of aldehyde moieties on AM membrane sialoglycoconjugates promotes positive macrophage-lymphocyte interactions, resulting in abrogation of AM-mediated suppression of the PFC response.