Efficient Propagation and Cloning of Human T Cells in the Absence of Antigen by Means of OKT3, Interleukin 2, and Antigen-Presenting Cells

The analysis of T lymphocytes infiltrating tissues afflicted by autoimmune diseases may provide major clues towards understanding the pathogenesis of such diseases. Currently the best approach to studying heterogeneous populations such as T lymphocytes involves long-term culture and cloning. In order to grow and clone T lymphocytes, regular restimulation with the specific antigen is essential, otherwise growth will stop and/or specificity may be lost. In autoimmune diseases the antigens involved in triggering the immunological reaction of T cells are usually unknown. Therefore an alternative way of stimulating T lymphocytes without loss of specificity is clearly needed. Here we describe the cloning and expansion of antigen-specific T cell clones from the blood of a healthy donor to sizeable numbers of cells (greater than 10(8)) by means of anti-CD3 monoclonal antibody and recombinant IL-2. The results obtained showed that this approach can be used to clone and 'expand' T lymphocytes that retain antigen specificity over a prolonged period, in this case over 10 weeks. This technique has been used to clone and expand T lymphocytes infiltrating the affected tissues in a variety of autoimmune disorders such as Hashimoto's thyroiditis, Graves' disease, and rheumatoid arthritis, and is an efficient method of propagating T cells, by mimicking the antigenic stimulus.