CD4+CD25+ lymphocytes play role in immune response to melanoma antigens.

2003 APR 9 - (NewsRx.com & NewsRx.net) -- CD4+CD25+ suppressor lymphocytes in the circulation of patients immunized against melanoma antigens may play a role in the immune response.

"Murine studies have suggested that a population of CD4+ T cells expressing the alpha chain of the interleukin (IL)-2 receptor (CD25+) are phenotypically anergic in response to T cell receptor stimulation and can suppress the function of CD4+ and CD8+ T cells. Recent studies of peripheral lymphocytes from healthy human volunteers have identified a similar population, although little is known about the presence and activity of these cells in patients with cancer and their possible impact on anticancer immunization strategies. Thus, the authors have undertaken these studies in patients with metastatic melanoma undergoing immunizations with known melanoma antigens," researchers in the United States report.

"CD4+CD25+, CD4+CD25-, and a 1:1 ratio of these isolated T cells were stimulated with soluble anti-CD3 antibody in the presence of irradiated T cell-depleted PBMCs, and proliferation was assessed by measuring [[superscript]3H]thymidine incorporation," stated Luv Ram Javia and Steven A. Rosenberg at the National Cancer Institute. "In 13 patients, isolated CD4+CD25+ T cells proliferated 68% ([+ or -]5.8%) less than separately cultured CD4+CD25- T cells. Moreover, CD4+CD25+ T cells suppressed the proliferation of an equal number of cocultured CD4+CD25+ T ...