The Place of the Rosette Inhibition Test in the Preparation and Assay of Antilymphocytic Globulin¹

Abstract

An anti‐dog thymocyte serum was prepared in six horses by four weekly injections of dog thymocytes, and was tested for immunosuppressive capacity during the course of immunisation by its ability to inhibit the formation of rosettes between dog spleen cells and sheep red blood cells. Antithymocyte globulin prepared from the individual sera was administered to dogs receiving renal allografts with simultaneous bilateral nephrectomy, and the prolongation of survival was correlated with the rosette inhibition litres (RIT) of the sera. A rise in serum RIT occurred after the third immunizing dose in all four horses producing immunosuppressive serum, with little or no response in the two horses producing non‐immunosuppressive serum. These observations have led to considerable saving in time and expense in the production of antithymocyte globulin for experimental and clinical purposes in our own laboratories, and we recommend that continued immunisation and final bleeding out should be performed only if such a rise in RIT has been demonstrated.

Antilymphocyte Serum: Studies of the Specificity of the Rosette‐inhibiting Antibody in Rabbit Anti‐mouse Als

“…The most satisfactory in vitro assay of this in vivo capacity is provided hy the rosette inhihition test (Bach et al, 1969;Morton et al, 1973;Hogg et al, 1973). Thus, a study of these mechanisms provides an opportunity for a more precise investigation of the mode of action of ALS.…”

“…Antilymphocyte serum appears to achieve its immunosuppressive action hy a selective depletion of T cells of the recirculating pool, perhaps hy a coating of susceptihie lymphocytes hy specific antihody (Lance, 1970). The most satisfactory in vitro assay of this in vivo capacity is provided hy the rosette inhihition test (Bach et al, 1969;Morton et al, 1973;Hogg et al, 1973). Thus, a study of these mechanisms provides an opportunity for a more precise investigation of the mode of action of ALS.…”

“…Since the rosette inhibition test forms a reliable in vitro assay for the immunosuppressive action of ALS (Bach et al, 1969;Morton, Hegh and Clunie, 1973;Hogg et al, 1973), it seems possible that the rosette-inhibiting antibody may also be the agent directed against recirculating lymphocytes in vivo. This series of experiments with rabbit anti-mouse ALS has been designed to investigate this postulate.…”