Macrophage binding of Staphylococcus albus is blocked by anti I-region alloantibody

Cell surface interactions involving carbohydrate may be important in immune recognition. Previous work from this laboratory has demonstrated the presence of 'lectin-like' receptors on mouse peritoneal macrophages that bind bacteria by means of their cell wall sugars. Others have shown that Ia molecules can bind antigen at specific sites which may be involved in presenting antigen to the immune system and recent work has shown that these molecules can carry carbohydrate determinants. It has also been found that human Ia molecules can bind to carbohydrates. As cell surface carbohydrate recognition mechanisms have been implicated in other immune interactions sugar-specific receptors may have a function in self--non-self recognition. We show here that the binding of the bacterium Staphylococcus albus to mouse peritoneal macrophages was inhibited by various conventional and monoclonal antibodies to Ia antigens suggesting that an I-region gene product may be associated with the binding of unopsonized bacteria.