Phenotype of CD4+CD11b+ and CD4-CD11b+ subpopulations of MHC IIhi cells in synovium-rich tissue at indicated times after adoptive transfer of arthritogenic thoracic duct cells. Cell surface phenotype was determined by four-color flow cytometry (Figure 4). The CD4+ (a) and CD4- (b) subpopulations of MHC IIhi CD11b+ cells identified in Figure 4 were assessed by use of a fourth fluorochrome. Proportions of the MHC IIhi cells expressing respective surface markers are shown. Means, n = 2. MHC, major histocompatibility complex.