Fibronectin and lymphocyte blast transformation.

Purified human plasma fibronectin (Fn) added to human peripheral blood leukocytes culture, from 22 healthy blood donors, phytohemagglutinin (PHA) stimulated, enhanced mitogen action in blast transformation. Daily measurement (between 1-6 days) of Fn concentration in culture supernatants incubated with PHA, Fn and associated doses of Fn and PHA, pointed out a significantly increased Fn concentration, on the fourth day, in the cultures incubated with Fn and PHA. On the fourth day of PHA stimulated cultures were found, the increased Fn concentration, as well as the maximum blast transformation. Our data suggest that Fn, synthetized by activated macrophage in intercellular cooperation processes is released in culture supernatants with a maximum on the fourth day. These results show the possible role of Fn to influence blast transformation enhancement of mitogen action.