Expression of p58 in fetal thymocytes and fetal liver lymphocytes.

Abstract

Bipotent progenitors for T and natural killer (NK) lymphocytes are thought to exist among early precursor thymocytes or liver lymphocytes. The identification of such a progenitor population or mature NK cells in such organs remains undefined. Here we report the identification of a novel receptor of NK cells, p58 (HLA class I-specific inhibitory receptors), in fetal thymocytes and fetal liver lymphocytes. Our finding suggests the NK cells mature in the developmental stage during feta1 ontogeny. Flow cytometric analysis revealed p58 positive cells in thymocytes or in fetal liver lymphocytes and reverse transcription PCR also showed amplification of p58 RNA. The result of single stranded conformational polymorphism (SSCP) showed it discriminates one or two base pair differences of the p58 gene. Although the question still remains as to whether the expression of p58 is due to the NK cells or natural T cells, it is clear the p58 is expressed in fetal thymocytes or liver lymphocytes. And SSCP analysis using appropriate sets of primers used in this study, is helpful to study the diversity of p58.