Prolonged Survival of Murine Fibrosarcoma Allotransplants by Anti-Enhancing Fab Alloantibody

Abstract

Anti-alloantibody whole molecules and subunits have been shown to inhibit specific recognition of foreign antigenic determinants by certain thymus-dependent lymphoid cells. The present investigation was designed to demonstrate whether anti-Fab and anti-Fc alloantibodies raised against Fab and Fc fragments prepared by papain digestion of tumor-enhancing IgG₂ could prolong the survival of C3H_f/He (H-2^k) fibrosarcoma allografts in TS (H-2^s) mice. Prolonged survival of tumor allografts was observed in TS mice that received anti-Fab alloantibody followed one hour later by tumor allotransplantation, whereas anti-Fc alloantibody showed no such effect when assayed under similar conditions. By contrast, no significant difference in allograft survival time was observed between TS mice that received anti-Fc alloantibody and control mice that received 0.15 M NaCl each followed within one hour by tumor allotransplantation. The injection of γ -globulin fraction of alloantisera absorbed with enhancing Fab fragments covalently linked to an insoluble matrix led to tumor allograft rejection complete by 14 days post inoculation. Results of this study are consistent with the concept that immunoglobulin-like molecules act as T-lymphoid cellular receptors in allograft rejection (i.e., a thymus dependent process).