LDR could stimulate lymphocyte transformation for adults, children and infants. The effeet of LDR on lymphocytes in malnourished children was lower,but higher on lymphocytes in cord blood. The effect of LDR on ,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=42067074&type=,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=42067076&type=,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=42067075&type=, cells in adult persons was higher than that on ,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=42067077&type=,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=42067094&type=,http://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=42067093&type=, cells. NK cells were radioresistant. The stimulative effect of LDR on NK activeity in tumor patients was lower than that in normal individuals. For the mice with tumors,LDR could increase the ratio of L,3,T,4, cells in blood, spleen and the number of cytotoxic T cells in the tumors. Extracellular fluid of the lymphocytes operated by LDR could also stimulate the lymphocyte transformation. The preliminary LDR could decrease the injuries to macromolecules membrane antigens and chromosomes in lymphocytes which were induced by high dose radiation. The LDR-induced protein might be found from mouse spleen cells,and this protein could increase immune function in human and animals.