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Islet autoantigen preparations for T cell assays

As many IDS members will be aware, the major goal of the T cell Workshops has been to identify and evaluate assays for detecting autoreactive T cells. During IDS T cell Workshop I it became clear that one of the potential problems in achieving this lay with the antigen preparations. For example, some of the antigens used in Workshop I were subsequently shown to be inadequate at stimulating antigen-specific T cell clones, or to contain contaminants which either stimulated or inhibited antigen-unrelated T cell responses. Many of these issues were highlighted and discussed in the Workshop I report (J Autoimmunity1999;13:267-282). One of the goals which was subsequently set by the T cell Workshop Committee was the acquisition and evaluation of islet autoantigens available in sufficient quantity and purity that they could be distributed to laboratories for assay development.

We believe that this stage has been reached. In response to the request for antigens, several were made available: GAD65 and IA-2 generated in insect cells (Peter van Endert, Paris); GAD65 generated in insect cells (Diamyd); GAD65 generated in E coli (Timothy Tree, London); a GAD65/67 fusion generated in yeast (Merrill Rowley, Victoria); and a proinsulin preparation generated in E coli and supplied by Eli Lilly. The quality of these preparations was evaluated in 3 ways: measurement of endotoxin levels, ability to stimulate antigen-specific T cell clones and degree of inhibition of T cell proliferation to other antigens. The details of these analyses will be made available in the near future. In the meanwhile, we are able to report that aliquots of preparations of insect cell GAD65, IA-2 and E coli proinsulin are available for distribution to laboratories.

The availability of these preparations reflects many months of work in numerous laboratories, and quantities of antigen will necessarily be limited. We propose that laboratories interested in obtaining these preparations should submit a brief proposal (no more than one page) indicating the use to which the antigens will be put. Proposals should include information on the cohorts to be studied, numbers of cases, the T cell assays to be used, and the ways in which results will be evaluated. Although it is important that some laboratories employ well established approaches (eg proliferation) approaches from groups involved in the development of novel techniques (eg ELISPOTS, T cell subset analysis) are particularly encouraged. The antigens will be coded and will include control preparations, but unblinded preparations can also be made available when necessary. It is envisaged that results from these efforts will be presented at dedicated sessions in and around the 5th IDS Meeting in Madras.

For further information, and to request participation, please contact Dr Mark Peakman (). Finally, we thank the Juvenile Diabetes Foundation for supporting this venture.

IDS T cell Workshop Committee
Dr Mark Peakman, Dr Mark Atkinson, Dr Bart Roep, Dr Margo Honeyman.