The effect of Rg1,a saponin extracted froin Panax ginseng, on the phenotype,receptor and the activity of protein tyrosine kinase (PTK) of lymphocytes isolated from 7 healthy oldpersons were studied. The CD25, CD45RA and CD45RO phenotypes of lymphocytes were 4eter-mined by indirect immunofluorescence technique. The percentage of CD25, CD45RA and CD45ROpositive lymphocytes was 38.3%±17.3%, 46.0% 15.1%, and 52.6%±14.1% respectively after incu-bation with PHA (5 μ±/ml) for 72 hours. However, there were 58.0%±12.5%, CD25, 64.1% ± 12.4%,CD45RA, and 74.0%±8.0%, CD45RO positive cells in the presence of Rg, ( 1μg/ml) along with PHA(5 μg/ml) over the sanie period of incubation. A significant increase was induced by Rgi (P<0.05).The activities of PTK in the cytoplasm and membrane of lymphocytes were measured by ELISAmcthod after incubation with PHA or PHA+Rg1. The absorbance value of PTK activity in cytoplasmafter 72 hr incubation was 0. 120±0.020 in PHA group, but 0. 1 38±0.015 in PHA+Rg1 group. In thelymphocyte membrane, it was 0.374± 0.060 in PHA group and 0.403 ± 0.008 in PHA+Rg1 group(P<0.001). These results showed that Rgi significantly arid simultaneously increased both the PT Kactivity and the expression of phenotype of lymphocytes.
