Efficient In Vitro Assay for Antigen-Specific Tolerance

Performed on the same 24-hour time scale as the DTH bioassay but requires far fewer cellsAvoids the need for vertebrate animalsAmenable to automation and miniaturizationSupports a variety of applications, including clinical laboratory use

In vitro assay for measuring an antigen-specific regulatory response in patientsIdentifying transplant recipients who are good candidates for cutting back or discontinuing immunosuppressionApplications in the cancer space, particularly in the area of DNA vaccines and immunotherapy

The ultimate goal of organ/tissue transplantation is drug-free acceptance, meaning the recipient’s body is able to tolerate the antigens derived from donor tissue (alloantigens). Unfortunately this scenario is rare, and immunotherapies with powerful side effects must be prescribed to prevent graft rejection.Research has shown that those patients who are able to tolerate their grafts experience an active suppression of their immune response to specific antigens. The potential to induce such tolerance could help other transplant recipients or patients with autoimmune disorders. To advance this research, UW–Madison faculty pioneered a method (called the trans vivo DTH bioassay) for measuring antigen-specific regulatory response in vertebrate animals. But there remains a need for a non-animal in vitro method.Building on their work, UW–Madison researchers have now developed a T cell-bound cytokine (T-CBC) assay for detecting and quantifying regulatory T cells specific to self-antigens or donor alloantigens. The new method comprises (a) culturing the subject’s T cells for 24 hours in the presence of one or more target antigens and (b) analyzing the cultured T cells for expression of a marker (EBi3; TGFβ/LAP) indicative of antigen-specific immune suppression.

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