| Several important physiological changes accompany the process of macrophage activation, and concominant alterations in cell surface properties have been observed. To study antigenic changes accompanying macrophage activation we have developed a monoclonal antibody recognizing a determinant on C. parvum and MVE-2-activated macrophages. This determinant has been termed Macrophage Activation Antigen-1 (MAA-1). MAA-1 is also expressed by a small number of thioglycolate-elicited macrophages.;Treatment of activated macrophage monolayers with anti-MAA-1 inhibits tumor cell binding in a dose-related fashion. Macrophage - mediated tumor cell cytostasis is not altered by anti-MAA-1. Thus, MAA-1 may be able to dissociate these two characteristics of macrophage activation. MAA-1 is a multimeric structure composed of subunits of approximately 75,000 and 25,000 molecular weight, joined by disulfide bridges. We have also identified a hybridoma clone which secretes an antibody directed primarily against resident or elicited macrophages. These tools may provide new information on macrophage differentation and additional insight into functional and structural membrane alterations that accompany such differentiation. |
