COVER: Antigen-expression of typical monocyte/macrophage-markers in co-cultures of elutriated monocytes and spheroids of the intestinal epithelial cell line HT-29. After 24 h of co-culture as demonstrated with single and double labeling techniques (CD68: brown; CD14, CD16, CD11b or CD11c: blue), MO/MAC were preferentially located at the spheroid surface and expressing all antigens. After 7 days of co-culture, expression of the surface was no longer detectable. This led to a macrophage phenotype similar to that found in normal colonic mucosa (see Spottl et al., pages 241-251).