The distribution of CD164 epitopes in adult nonhematopoietic tissue sections.

Frozen sections of colon stained using the immunoperoxidase technique with the 105A5 (A), 103B2/9E10 (B), N6B6 (C), and 67D2 (D) CD164 Mabs revealed that the 105A5 epitope was expressed by infiltrating lymphoid cells and macrophages in the laminar propria (A), the 103B2/9E10 epitope by vacuolar membranes of the goblet cells, with weak expression on the epithelium of the villi and crypts, and the N6B6 and 67D2 epitopes were expressed by both the 105A5- and 103B2/9E10-positive cells. The 9C4 Mab stained the vacuolar membranes of the goblet cells and the epithelium strongly, as is illustrated using the immunoperoxidase (E, F) or immunofluorescence (I) methods, while its isotype-matched control Mab, mIgG2b, was negative (inset G). Sections were triple-labeled with 103B2/9E10 (red), 9C4 (green), and DAPI (blue) for the detection of the cell nucleus using the immunofluorescence technique. Single-color analyses with 103B2/9E10 (H) confirmed that both the vacuolar membranes of goblet cells and endothelium were positive, with weaker labeling of the apical epithelium of the villi and crypts. In contrast, 9C4 did not label endothelia (I). Triple-color analyses (J, K) confirmed the strong coexpression of 103B2/9E10 and 9C4 on goblet cell vacuolar membranes (yellow). A comparison of reciprocal immunofluorescence staining of colon (L) and tonsil (O) sections with the 103B2/9E10 (red) and 105A5 (green) Mabs is shown. Double-stained cells (yellow; O) are macrophages. A skin section incubated with the 103B2/9E10 Mab demonstrates positive immunoperoxidase staining of basal epithelia and endothelia (M), while that stained with CD31 (N) shows endothelial staining only. Original magnifications: (A-G, L) ×90; (H-K) ×240; (M, N) ×70; O ×400.