Measurement of the Radiosensitivity of Rat Marrow by Flow Cytometry

摘要

Monoclonal antibodies directed against the three major glycoproteins of rat thymocytes were found to be useful for identifying hematopoietic stem cells by flow cytometry. These antibodies and their specificities are OX-7, which recognize a determinant expressed on the Thy 1.1 membrane glycoprotein; OX-22, which recognizes the high molecular weight form of the leukocyte common antigen; and W3/13, which identifies some leukocyte sialoglycoproteins. In previous studies, (McCarthy Et al., 1985, 1987; Hale et al., 1987) it was determined that the rat hematopoietic stem cell (HSC), colony-forming unit spleen (CFU-S), and prothymocyte had the phenotype of OX-7 upper 20% positive (OX-7up20%) and OX-22. This subpopulations could be further divided into two further subpopulations, a W3/13 dim and a W3/13 positive population, each representing approximately 0.17% of the total marrow cell population. Ongoing research indicates that the HSC is W3/13 dim. The agreement between the clonogenic CFU-S and phenotypic flow cytometry assays for determining the size of the HSC compartment led us to attempt to measure the radiosensitivity fo the HSC by flow cytometry. The results of these experiments are compared with radiation survival curve generated using the classical CFU-S clonogenic assay for HSCs, which is generally used when estimating the protective effects of drugs against hematopoietic damage. Keywords: Ionizing radiation, Whole body irradiation, Cobalt 60, Radiation dosage, Reprints. (aw)