Enzyme Analysis of Autologous Rosette‐Forming Cells

Autologous rosette-forming cells (ARFC) have been considered to be post-thymic precursor cells. Since thymocytes and peripheral T lymphocytes differ considerably in lactate dehydrogenase isoenzyme pattern and in activity of the enzymes of the purine metabolism, we investigated the enzyme profile in the ARFC. The L-lactate:NAD+ oxi-reductase analysis showed an isoenzyme pattern that closely resembled the pattern found in peripheral T lymphocytes and was totally different from the thymocytes. The levels of adenosine deaminase and purine nucleoside phosphorylase were identical to those found in the peripheral T lymphocytes and different from thymocytes. In our hands, the ARFC-enriched suspension contained predominantly OKT4+ and Tμ+ lymphocytes. We propose that ARFC are a heterogeneous population encompassing all known subsets and cannot be considered a separate homogeneous entity.