Role of Thy-1 antigen in the in vitro differentiation of a rat mammary cell line.

Abstract

A line of rat mammary [carcinoma] cells, LA7, undergoes differentiation into domes or ridges or projections under partial medium control. Immunofluorescent studies show that at the time of dome formation the LA7 cultures express the Thy-1 antigen at the borders between cells. Exposure of the cultures to certain monoclonal anti-Thy-1.1 sera prevents formation of new domes and causes disappearance of pre-existing ones; antisera to whole cells produce no visible effect. Cultures exposed to anti-Thy-1 sera at effective concentrations of antibody against domes show morphological changes and ridge formation. The specific interaction of these antisera with the Thy-1 antigen may redirect the differentiation program of the cells.