Long-Term Survivor Shows Tumor-Specific Immune Response.(Brief Article)

2001 JUN 13 - (NewsRx.com & NewsRx.net) --

by N.R. Saltmarsh, staff medical writer - Solving the mystery of long-term survival in people with a deadly form of cancer could help scientists gain critical insight for vaccine development.

G. Yamshchikov and colleagues analyzed such a case of natural immunity in a patient with metastatic melanoma who had remained disease-free for six years. Their findings reveal specific cytotoxic T lymphocyte (CTL) reactivity in lymph node tumors, and in peripheral blood.

Using an ELISPOT assay to evaluate lymphocytes from tumor-involved nodes, the researchers detected naturally occurring functional T cells and two other HLA-A3 restricted peptides. The T cells were CD8(+), CD45RO(+), L-selectin(-), and CD11a(+), "suggesting that they are antigen experienced and have a memory phenotype," said Yamshchikov and coauthors.

When stimulated with the peptide ALLAVGATK (gp100(17-25)) in vitro, the patient's peripheral blood lymphocytes dramatically increased their production of peptide-reactive CTLs, the researchers found.

Three patients with rapidly progressive metastatic melanoma, on the other hand, showed no such T-cell response, either in tumor-involved nodes or peripheral blood lymphocytes stimulated ex vivo with ...