Patterns of in Vitro Labeling of Bone Marrow Lymphocytes and Antibody-producing Cells with Tritiated Thymidine and Deoxycytidine
Difference between the Two Cell Types
1980 Volume 57 Issue 2-3 Pages 89-96
Details
1980 Volume 57 Issue 2-3 Pages 89-96
Previous studies have revealed that among lymphocytes, two different types can be distinguished based on their patterns of labeling with 3H-thymidine (3HdThd)and/or 3H-deoxycytidine (3HdCyd). Thymic lymphocytes and germinal-center cells are to a large extent capables of utilizing deoxycytidine (dCyd) for the formation of DNAthymine. However, in such cells as pyroninophilic blast cells (or immunoblasts) and plasma cells, the capacity for utilizing dCyd is very limited. In the latter cells, the labeling intensity with 3HdThd is far stronger than that with 3HdCyd, but this is not the case for the former cells.
In the present study, investigations were made of the patterns of in vitro labeling with 3HdThd and/or 3HdCyd of bone marrow lymphocytes of the guinea-pig and hemolytic plaque-forming cells (PFC) of the spleen of mice which had previously been stimulated with sheep red blood cells. The ability of these cells to utilize dCyd for the synthesis of DNA-thymine was also assessed. It was found that the bone marrow lymphocytes were as heavily labeled with 3HdThd as they were with 3HdCyd, but the antibodyproducing PFC showed far more intensive labeling with 3HdThd than with 3HdCyd. It was also found that the bone marrow lymphocytes had a strong capacity for utilizing dCyd in DNA-thmine formation, whereas such a capacity was very limited in the antibodyproducing PFC. These results indicate that, as regards patterns of labeling with radioactive deoxyribonucleosides, bone marrow lymphocytes are identical with thymic lymphocytes and germinal-center cells, but antibody-producing PFC are similar to pyroninophilic blast cells (or immunoblasts) and plasma cells. The significance of these findings is discussed in relation to the differentiation of lymphocytes and the pathways of DNA synthesis.
It is concluded that, during the process of differentiation of bone marrow lymphocytes into antibody-producing cell, the pathway of dCyd utilization for DNA-thymine formation is partially or completely blocked.
