A monoclonal antibody disrupting calcium-dependent cell-cell adhesion of brain tissues: possible role of its target antigen in animal pattern formation.

The Ca2+-dependent cell-cell adhesion system (CDS) is thought to be essential for the formation and maintenance of cell adhesion in a wide variety of tissues. Previous studies suggested that CDS has some cell-type specificity; for example, the monoclonal antibody ECCD-1 selectively recognizes CDS of certain epithelial tissues in mouse embryos but not nervous tissues. In the present study, we have obtained a monoclonal antibody, designated NCD-1, that disrupts connections between brain cells of mouse embryos. A series of experiments suggested that NCD-1 specifically recognizes CDS. We then determined the distribution of the NCD-1 antigen in various mouse tissues. NCD-1 reacted with cells of the following tissues and cell lines: nervous tissues from various sources, lens, striated muscle, cardiac muscle, glioma G26-20, adrenocortical tumor Y1, and melanoma B16. None of these cells reacted with ECCD-1, and the cells reactive with ECCD-1 did not react with NCD-1. There was also a class of cells that did not react with either ECCD-1 or NCD-1. These results suggest that cells in the body can be classified into at least three groups containing CDS of differing specificities. A map of the tissue localization of these different classes of CDS also suggests that the expression of cell-type-specific cell adhesion molecules in each tissue plays a crucial role in adhesion between the same cell types and segregation of different cell types in processes essential for animal morphogenesis.