Changes in concanavalin A agglutinability during development of the inner cell mass and trophoblast of mouse blastocysts in vitro.

Mouse blastocyst cultures were analysed for Concanavalin A (Con A) agglutinability by microhaemadsorption methods and for Con A binding capacity with Rhodamine-Con A stain. The inner cell mass, which was not agglutinable in the early culture stages, became agglutinable when it started to develop. The trophoblast, which was initially agglutinable, lost this property as the cells matured. There was no apparent correlation between changes in agglutinability and capacity to bind Rhodamine-Con A. The pattern of change in Con A agglutinability which characterized development of the inner cell mass and trophoblast is consistent with an interpretation that agglutinability was related to the migratory activities of these cells. The loss of agglutinability associated with trophoblast maturation may have been due to alterations in Con A receptor accessibility.