There is a need for epidemiology studies examining the role of cellular immune response to environmental risk factors in autoimmunity. These studies will require the development of assays of cell-mediated immunity to assess exposure and immune response to candidate environmental pathogens/xenobiotics. Nearly all of the immune monitoring of field-collected samples consists of assay of humoral immune response. Assays of cellular immune response, of which the lymphocyte proliferation of T cell assay (LPT) is most utilized, have been difficult to adapt to the field. The ELISPOT (enzyme-linked immunosorbant spot) assay is an alternative method to examine T cell immune response in vitro. The proposal examines the hypothesis that the ELISPOT is a more sensitive and reliable assay for evaluating T cell immune response to environmental factors than the standard LPT assay. Furthermore, the proposal seeks to develop ELISPOT to detect cellular immune response to human heat shock protein for future epidemiological studies.