Phenotypic Characteristics and CD2- and CD3-mediated Signal Transduction in HLA DR Positive and Negative Subsets of Lamina Propria-like T-cells

Kim, Won Ho; Kim, Hyun Soo; Lee, Chung Ryul; Moon, Young Myoung; Kang, Jin Kyung; Park, In Suh; Targan, Stephan R

Abstract

BACKGROUND/AIMS: Peripheral blood T-cells co-cultured with Daudi (a irradiated B-cell line) and interleukin (IL)-2 attain a CD2 dominant cytokine secretion pattern and show tyrosine phosphorylation profile identical to freshly isolated lamina propria (LP) T-cells. Since the phenotypic characteristics and signal transduction pathway of these LP-like T-cells are largely unknown yet, we have explored the expression pattern of T-cell markers and CD2 ligation-induced tyrosine phosphorylation profile of LP-like T-cells and their HLA DR+ and DR- subsets.
METHODS
The LP-like T-cells were sorted into DR+ and DR- subsets by magnetic sorting. Surface markers were measured by flow cytometry. Tyrosine phosphorylation profile was investigated by Western blot.
RESULTS
The LP-like T-cells consisted of two distinct populations: approximately 55% of the cells express both HLA DR and IL-2R (DR+ LP-like T-cells) and the remainder express neither HLA DR nor IL-2R (DR- LP-like T-cells). Approximately 80% of DR+ LP-like T-cells were memory cells expressing CD45RO and 2/3 of them were activated T-cells expressing CD69, CD71 and CD30. In contrast, 50% of DR- LP-like T-cells expressed CD45RO and only 10-20% of them expressed activation markers. Tyrosine phosphorylation of p72 protein after CD2 ligation was identified only in DR- LP-like T-cells.
CONCLUSIONS
The LP-like T-cells consist of two distinct subpopulation in terms of phenotype and tyrosine phosphorylation pattern according to CD2 ligation.