A previous study demonstrated that macroglobulin enhanced radiation recovery of hemopoietic tissue. In the present study isologous serum alpha macroglobulin was found to be most effective in promoting regeneration of hemopoietic cells when given shortly after x-irradiation. This effect was enhanced by repeated doses. Macroglobulin had only a slight effect on the hemopoietic cells of unirradiated mice. The macroglobulin of two mouse strains and Sprague-Dawley rats was tested and was found to enhance radiation recovery across strain and species barriers. A dose response of the macroglobulin effect was established.
