Demonstration of Cytotoxic Humoral Substances during the Course of First Set Skin Allograft Rejection

SummaryCytotoxic humoral substances, which are most likely produced by the stimulation of first set skin allograft, were demonstrated by utilizing Millipore diffusion-chamber technique. The cytotoxic effect of the substance was much stronger in the animals which had rejected their grafts, whereas it was least in the animals bearing viable grafts. The presence of such cytotoxic humoral substances was observed as early as 8 days after grafting, and lasted for at least 6 weeks. The results obtained at the twelfth week of grafting suggested the virtual disappearance of the cycotoxic substances. Lymphocytes originating from a rat other than the skin graft donor were also killed rapidly when implanted into recipient rats which had rejected grafts, indicating cross-reactivity within the animals used in this study.