Relationship between reaggregability of monolayer cultured chick embryonic liver cells and their surface properties

When liver cells dissociated from 10-day-old chick embryos were cultured as monolayers, the reaggregability of the harvested cells declines steeply with time of cultivation. Immunological and virological techniques were used to detect cell surface changes during monolayer cultivation. An early rapid increase in Forssman (F) antigen was demonstrated by the complement fixation test and the fluorescent antibody technique. An increase parallel to that of F antigen was also found, using the hemagglutination inhibition (HI) test, in the receptor activities of these cultured cells for Japanese encephalitis (JE) virus and influenza virus. The reaggregability recovered with receptor-destroying enzyme (RDE) from Vibrio chorelae. Therefore, we concluded that a cell surface change or aberration, recognized as an increase in the biologically identifiable determinant sites such as F antigen and virus receptors, was responsible for the loss of reaggregability. In contrast, we confirmed that the intracellular machinery required for JE virus multiplication never changed during protracted monolayer cultivation.