Effects of dialyzable leukocyte extracts with transfer factor activity on leukocyte migration in vitro. V. Antigen-specific lymphocyte responsiveness can be initiated by two structurally distinct polyribonucleopeptides

Abstract

Human transfer factors (TF) active in specifically inducing responsiveness in human thymus-derived (T) lymphocytes previously nonresponsive to purified protein derivative from Myobacterium tuberculosis (PPD) or to Coccidioides immites (Cocci) in vitro were isolated from the dialyzable portion of extracts of immune leukocytes (DLE). Each TF segregated into two active fractions after high-pressure reverse-phase liquid chromatography (HPLC), suggesting the presence of two TF components in DLE for each antigen specificity. Determination of the structures of both TF components specific for PPD was accomplished by evaluating their activity after incubation with various endonucleases, exonucleases, phosphatases, peptidases and a protease. The results indicated that both PPD-specific TF components are oligoribonucleopeptides but that they are structurally distinct. Simplest-case molecular models were constructed on the basis of the data obtained.