Formation of spontaneous hematopoietic colonies in semisolid cultures of lymphocyte enriched fractions of peripheral blood from beagles

The formation of hematopoietic colonies in semisolid cultures derived from lymphocyte enriched fractions of canine peripheral blood is described. Such colonies occurred in the absence of either mitogens or colony stimulating factor. Although the mechanism(s) involved in such colony formation is not known, preliminary results suggest an increased tendency for spontaneous colony formation with age and a possible relationship to low-level irradiation and neoplasia. The observation underlines the importance of doing nonmitogen stimulated control cultures in order to determine the true influence of mitogens or growth factors on colony formation