Lack of Inverse Relationship Between the Net Charge of T-Independent Immunogens and the Responding Spleen Cells

Abstract

Previous studies have demonstrated an inverse relationship between the net electrical charge of immunogens and the antibodies they elicit. This correlation was found to be expressed at the cellular level. It has been shown that thymus-derived cells may recognize immunogens on the basis of their overall electrical charge. In this study, charged T-independent copolymers composed of tyrosine, glutamic acid, and lysine of the D configuration were prepared in order to find out whether this net charge phenomenon holds also for immunogens which do not require helper T cells for generation of immune response. Spleen cells were fractionated over negatively charged glass bead columns, and their immunocompetence was tested by transferring them into irradiated recipient mice which were immunized with the dinitrophenylated acidic or basic T-independent carrier. No differences in the responsiveness to the dinitrophenyl group on either carrier could be detected in recipients of unfractionated or fractionated cells on the charged columns. Similar results were obtained with the negatively charged T-independent branched polypeptide poly(DTyr,DGlu)-poly(DPro)--poly(DLys). Filtration of spleen cells through glass bead columns did not affect the immune response potential of the recipient mice. In contrast, a significant reduction was observed in the frequency of positive responses in recipients of filtered cells, which were immunized with the negatively charged T-dependent poly(DTyr,DGlu)-poly(DPro)--poly(DLys). Thus, the inverse net charge phenomenon holds only for T-dependent antigens.