Studies on production of biologically active substances which inhibit cell migration in supernatants and extracts hypersensitive lymphoid cells incubated with specific antigen in vitro

When lymphoid cells from hypersensitive rabbits are incubated with antigen, biologically active substances are formed and released which are capable of inhibiting the migration of normal non-sensitized mesenchymal cells. In the present paper some basic parameters of their production were determined. These substances were regularly obtained after 6 and 18 hours incubation, but not after 2 hours. Under more favourable cultivation conditions (lower density of lymphocyte suspension) an increased activity in the cell extracts as compared with the supernatants was observed.