Mice of the (LxA)F1 strain were exposed to an ld100 dose of x-rays (870 r), and injected with bone marrow cell suspensions from A-strain mice. Excellent protection against death was observed during the first 3 weeks, followed by secondary ‘homologous’ deaths during the ensuing weeks. When A-strain (parental strain) spleen cells were injected, together with A-strain bone marrow, the protective effect was annulled. When A-spleen cells were injected together with LAF1 bone marrow cells into irradiated LAF1 mice, again no protection was observed. However, injected LAF1 spleen cells did not influence adversely the course of protection of x-irradiated A-strain mice by injected A-bone marrow. The findings formed the basis for an experimental test system for detecting the presence of A-lymphoid cells in the tissues of irradiated LAF1 mice which had been injected with A-bone marrow. The data indicate that the spleen and thymus of LAF1 mice 21 days after irradiation and injection of A-marrow contain A-lymphoid cells which when injected, in turn, into irradiated LAF1 mice treated with LAF1 marrow, annuls the protective effect of the injected marrow. It is concluded that a reaction (of an immunological nature) of the injected bone marrow cells, or their progeny, against the host tissues, contributes to the phenomenon of the late deaths. The significance of these results with respect to the problem of ‘homologous disease’ in lethally x-irradiated mice treated with homologous bone marrow, has been discussed.
Protective effect of Hemidesmus indicus R.Br. root extract against cisplatin-induced cytogenetic damage in mouse bone marrow cells