Effect of monoclonal anti-αLβ2, -αMβ2 and CD54 on monocyte adherence to tumor cells under flow conditions in the presence or absence of sFn. Anti-αLβ2 inhibited monocyte adherence to untreated cells (P <0.05; n = 3), but was significantly (P < 0.01 compared to non-sFn treated cells; n = 3) less effective in blocking monocyte binding to sFn pre-treated tumor cells. Conversely, anti-αMβ2 inhibited monocyte adherence to sFn pre-treated tumor cells to a significantly (P < 0.01) greater extent than to untreated tumor cells. Anti-CD54 inhibited monocyte adherence to untreated tumor cells by over 50%, and by over 80% when tumor cells were pre-incubated with sFn. Isotypic control IgGs or an irrelevant monoclonal antibody (CD4) did not affect monocyte adherence.