Experimental manipulation of cell surface to affect cellular recognition mechanisms.

The mechanism of selective cell adhesion was studied using Chinese hamster V79 and chick embryonic neural retinal cells. Both of these cell types have been shown to have two experimentally separable mechanisms of adhesion; Ca²⁺-dependent and Ca²⁺-independent. Cells can be dispersed so that either or both of the mechanisms remain intact by use of different treatments. A method of labeling cells with FITC was devised to identify one of the two types of cells in a binary cell population. When cells with one of the two adhesion mechanisms were mixed with cells with the other mechanism, they segregated completely, forming independent aggregates, not only in the heterotypic combination of these cell types but also in the homotypic combination of each cell type. In contrast, when cells were mixed with others with the same adhesion mechanism, either Ca²⁺-dependent or -independent, they formed chimeric aggregates, even in the heterotypic cell combination. These results suggest that the specificity in each of those two mechanisms of cell adhesion plays an important role in cellular recognition processes.