Macrophage-mediated phagocytosis is modulated by HSPs. The ability of macrophage cell lines (as indicated) to phagocytose either Alexafluor-labeled inert microspheres or S cerevisiae or E coli in the absence or presence of each of the HSPs indicated (HSP70, HSP90, or gp96) or serum albumin (MSA) was tested in vitro. HSP-mediated phagocytosis was quantified by measuring the internalized fluorescence measured by FluorImager SI, and relative mean fluorescence intensity (RMFI) was compared between the treatment groups (as indicated). All the treatment groups were compared with medium alone using the Student t test, and significance was denoted by P < .01. The error bar represents 1 SD. The results shown are a cumulative analysis of 3 experiments, 3 wells/group. ^*P < .05 when compared to medium.