Glen N. Gaulton

The effect of anti-interleukin-2 receptor monoclonal antibody on allograft rejection.

During immune response to an allograft, activated T cells express a number of cell surface activation antigens, among them the membrane receptor for the lymphokine interleukin 2 (IL-2). As the IL-2 receptor is not present on resting T cells, it offers an attractive target for potentially specific immunosuppressive therapy. The rat monoclonal antibody M7/20, which binds to the murine IL-2 receptor, was studied for its effect on allograft survival in two H-2-incompatible strain combinations in inbred mice. Treatment with M7/20 for 10 days markedly prolonged survival of vascularized, hetero topic heart allografts in both strain combinations, with indefinite graft survival in 50% of recipients. The same treatment significantly prolonged skin allograft survival in one of the two combinations. The results support the important role of the IL-2 receptor in the mechanism of graft rejection and confirm its suitability as a target for immunosuppressive therapy in transplantation.

Anti-idiotypic antibodies as probes of cell surface receptors

SummaryAnti-idiotypic antibodies have proven to have unique applications as probes in both functional and biochemical studies of cell surface receptors. Anti-idiotypic receptor antibodies have been prepared to antibodies which bind to purified ligand, as in the case of insulin, retinol-binding protein, the mammalian reovirus receptor, and the neutrophil chemotatic receptor, and to natural ligand analogs, such as the beta-adrenergic antagonist alprenolol. These systems have documented the usefulness of anti-idiotypic antibodies in the quantitation and modulation of specific membrane receptors on a variety of cell types. Anti-idotypic antibodies have also been utilized for the isolation of specific membrane receptors, e.g., reovirus and B-1 H globulin receptors. Some anti-idiotypic receptor antibodies, e.g., insulin and reovirus systems, have been shown to mimic the physiological properties of ligand upon binding to cellular receptors. These antibodies enable a new dimension of both receptor based cellular studies and therapeutic regimens. This review focuses on the past use of anti-idiotypic antibodies as probes of cell surface receptors, and on the methodologies required for the successful application of anti-idiotypic antibodies for use in further membrane receptor studies, and of the genes which encode and regulate these receptors. We also discuss the use of anti-idiotypic antibodies in the understanding of and therapeutic approach to receptor related diseases.

Characterization of a monoclonal rat anti-mouse interleukin 2 (IL-2) receptor antibody and its use in the biochemical characterization of the murine IL-2 receptor

Anti-murine interleukin 2 (IL-2) receptor monoclonal antibodies (mAb) were made from rats immunized with murine cytotoxic lymphocytes. One mAb, designated M7/20, strongly inhibited the proliferation of both IL-2 dependent CTLL-2 cells and concanavalin A (Con A)-induced T-cell blasts. Inhibition was linearly dependent on the concentrations of both M7/20 and IL-2. Utilizing FACS analysis, M7/20 was shown to bind selectively to mitogen-activated T lymphocytes and, to a lesser degree, to activated B lymphocytes. 125I-Labeled M7/20 binding assays indicated that 48-hr Con A-induced T-cell blasts possessed 89,000 binding sites/cell with a Kd of 1.2 X 10(-9) M. Competitive binding analyses indicated that M7/20 and IL-2 occupy the same or overlapping cell surface sites. Preliminary biochemical characterization of M7/20 immunoprecipitates of detergent extracts from both surface-iodinated and internally D-[3H]glucosamine-labeled T lymphoblasts indicated that the murine IL-2 receptor is an N-glycosylated 58,000-Da glycoprotein. Together these results suggest that mAb M7/20 binds at or near the IL-2-binding epitope on the murine IL-2 receptor and, thus, upon manipulation may act as an IL-2 agonist.

Comparison of protein phosphorylation induced by mitogen and phorbol diester stimulation of murine T and B lymphocytes

The cellular response to many external stimuli is initiated by soluble mediators or factors which interact with specific membrane receptors. The consequences of these interactions are activational signals which are then transduced across the plasma membrane resulting in an altered cellular response. The mechanism by which signals generated at the cell membrane are transduced and translated into the activational program of the cell is currently an area of intense interest. Perhaps the most actively studied cell with respect to receptor-mediated control of growth and differentiation is the lymphocyte. Phenotypically and functionally, lymphocytes are divided into two types: T and B lymphocytes. Activation of each type involves a complex series of receptor-mediated signalling events. Ligand interaction with the clonally distributed antigen receptor has been shown to generate primary activation signals

Anti-Interleukin-2 Receptor Monoclonal Antibody Treatment Prolongs Allograft Survival

We have attempted to selectively target immunosuppressive therapy to those clones able to mount cardiac graft rejection. As recently activated, but not resting or memory T cells bear receptors for interleukin-2, we have treated rodent (mouse and rat) cardiac graft recipients with anti-interleukin-2 receptor monoclonal antibodies. Such treatment has been remarkably successful. Despite short courses of treatment, a significant number of recipients are permanently engrafted.

Virus Receptors on Somatic and Immune Cells

The susceptibility of cells to viral infection is often determined during the early stages of interaction.1 This is particularly evident in the mammalian viruses, where infection and virus disease are largely determined by the ability of viruses to bind to the cells of a particular species. Even within a given species, the expression of different genes in different cell types or within the same cell type at different stages of development can result in the formation of different sets of specific virus receptors. The identification of virus receptors and the study of their interactions with ligands are therefore of critical importance in understanding viral tropism and subsequent disease patterns.2,3