Lactate dehydrogenase isoenzyme pattern of the pre-thymic precursor cell.

The thymic cell precursor was obtained from thymic rudiments of 14 day old mouse embryos of strain NMRI. The LDH isoenzyme pattern of this cell population showed a higher LDH-5 activity than the cortical and medullary thymocytes. These results indicate that during the T-cell development, a shift in the pattern occurs towards the LDH-1 end of the spectrum, as described for other murine tissues and cells. As cortical thymocytes contain less LDH-5 activity than the medullary thymocytes, however, the outcome of the latter cells from the former is in conflict with the shift toward the LDH-1 end of the spectrum. On the contrary a relationship whereby cortical and medullary thymocytes are independently derived from the thymic cell percursor, is consistent with the shift toward LDH-1.