The AIDS Clinical Trials Unit (ACTU) Immunology Support Laboratory (ISL) at UC Davis is one of only 6 NIH-sponsored AIDS Clinical Trials Group (ACTG) Immunology Support Laboratories nationwide. Under the direction of Dr. Richard B. Pollard, MD and managed by Dr. Xiao-Dong Li, MD, PhD, the ISL performs both routine and developmental immunologic assays on samples from patients enrolled in clinical trials sponsored by the ACTG. This includes measurements of lymphoproliferation to antigens of HIV and opportunistic infections, production of cytokines to these same antigens and measurement of cytolytic T-cell responses with the use of ELISPOT techniques. The laboratory also performs a variety of flow cytometry based assays including single cell assays of cytokine markers. Other more sophisticated assays are planned for development over the next several years. All assays are quality controlled and data is reported to a group central database shortly after it is developed. This laboratory, along with the other five located throughout the U.S., offers a substantial resource to the ACTG in understanding the immunologic consequences of clinical interventions being studied.