Adoptive immunization in the production of Lyt and other alloantisera

Abstract

Immunogenetic cell-surface markers that distinguish sets and subsets of lymphocytes, representing different stages and different lines of maturation within the total lymphoid population, have proved to be oI great value. They have helped to elucidate the immunological functions of different lymphocyte sets, and .have led to findings of much interest in other branches of biology. A serious impediment to wider use of such serological techniques is that the antisera required are often difficult to produce. Among the main problems is that, commonly, only a few immunized mice produce antiserum of adequate titer in the cytotoxicity assay, and of these, many must be discarded because they produce too much T-cell autoantibody. Thus, the volumes of satisfactory antiserum available are grossly inadequate. For this and other reasons (discussed below), we have explored the possibility that antiserum production can be improved by adoptive transfer of lymphoid cells from satisfactorily immunized donors to irradiated syngeneic recipients. The following progress report is sufficiently promising to warrant the attention of interested colleagues. The data refer exclusively to the cytotoxicity assay performed according to Boyse and coworkers (1970) with this exception: we no longer use preabsorbed rabbit serum as the source of complement. In our experience, the best and most ample source of complement is a pool of serum from a few among many rabbits whose serum has been rigorously screened (both before and after exsanguination) for low toxicity for mouse thymocytes combined with high lytic efficiency for thymocytes in cytotoxicity assays with an Lyt antiserum which has a high demand for complement. The conditions for testing the use of adoptive immunization in the three antigenic systems named below were: (i) All mice were females. (ii) All donors had a satisfactory record of antibody production, as defined below for each system, and had reached the limit of their usefulness after many immunizations and bleedings; we could not afford to sacrifice younger donors for an untried procedure. (iii) For adoptive immunization, each syngeneic recipient (aged 8-12 weeks) was subjected to 500R total-body irradiation (Gamma Cell/40, Atomic Energy of Canada, Ltd.)