Modulation of TL (Thymus-Leukemia) Antigens by Fab-Fracments of TL Antibody

[摘要] Cytotoxic antibodies of H-2 and TL specificities were located in the same 7 S γ-globulin fraction of mouse antiserum. The anti -TL and anti -H-2 activities occurred together in antiserum fractions prepared by Sephadex G 200 gel filtration or by electrophoresis in a Geon block. The modulating activity of TL antiserum (i.e., its capacity to cause the TL + → TL - phenotypic change in cells exposed to the antiserum in the absence of lytic C′) also occurred in the 7 S γ-globulin fraction. When γ-globulin prepared from antiserum by Geon block electrophoresis was digested with papain, cytotoxic activity of both H-2 and TL specificities was lost, but TL modulating activity remained. Thus attachment of univalent TL antibody fragments (Fab) lacking the complement-fixing and other biologic properties of the Fc-fragment was sufficient to induce modulation. Papain digests of H-2 antibody prepared in the same way did not induce modulation of H-2 antigen or of TL antigen, indicating further that modulation of TL antigen is a specific response to TL antibody.

[学科分类] 生物科学（综合）