Evidence for a less differentiated subpopulation of lymphocytes in people of advanced age.
The ratio of the lactate dehydrogenase subunits, H/M, is shifted toward lower values in thymocytes, and in high-density T cells in normal peripheral blood. The results presented here indicate that the T cells, but not B cells or monocytes, of donors greater than 75 years' old have a significantly reduced H/M ratio relative to young adults. This reduced H/M ratio appears to be correlated with a diminished percentage of OKT3 positive cells in the old donors. However, the density distribution of cells from young and old on Percoll gradients indicates that the T cells with lower H/M ratio in the elderly may represent a distinct, and possibly unique, less differentiated T cell type.
D000368:Aged; D000911:Antibodies, Monoclonal; D002454:Cell Differentiation; D002469:Cell Separation / Q000379:methods; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood*; D007958:Leukocyte Count / Q000379:methods; D008214:Lymphocytes / Q000166:cytology*; D008297:Male; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000201:enzymology
D000911:Antibodies, Monoclonal; D007527:Isoenzymes; D011947:Receptors, Antigen, B-Cell; D007770:L-Lactate Dehydrogenase