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The percent and absolute content of T helpers increases in the spleen of mice 4 and 17 h after resection of the liver or removal of a kidney, which is associated with an increase of the mitotic index of splenocytes. The number of T suppressors and the bone marrow cell mitotic index are unchanged. The T-helper/T-suppressor ratio in the spleen increases 1.7–2 times during surgery on the liver and kidney.

Transplantation of allogenic bone marrow from HLA-identical sibs to patients with acute and chronic leukemia receiving immunosuppressive therapy is associated with the appearance of erythrocytes simultaneously carrying donor and recipient antigenic markers: AB0 system, rhesus factor and its subtypes, M and N antigens. Integration of genes responsible for each antigen is realized independently presumably at the level of stem cell, which ensures long-term (3 years) repopulation of these erythrocytes. Experiments on inbred mice showed that transplantation of allogenic bone marrow is associated with an increase of chromosome number in 39% bone marrow cells 4 days after transplantation, which indicate the possibility of integration of whole chromosomes.

Laboratory of Immunology, G. N. Gabrichevskii Moscow Research Institute of Epidemiology and Microbiology. Laboratory of Growth and Development, Research Institute of Human Morphology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 105, No. 4, pp. 464-466, April, 1988. Original article submitted April 20, 1987.

At the age of 3 weeks, C57BL mice have comparatively low proliferative activity of their hepatocytes when the liver grows normally, but also during regeneration of the liver 44 h after its extensive resection (mitotic index 16%). Animals of the same age but of other strains (noninbred, CBA, and CC57BR), however, in most cases have a higher mitotic index of their hepatocytes both under normal conditions and during regeneration of the liver (42, 70, and 60%). This pattern of interlinear differences in mitotic activity of the hepatocytes during growth and regeneration of the liver was still found 7 days after the beginning of the experiment. The results indicate genetic determination of the level of proliferative activity of cells.

Transplantation of lymphocytes from partially hepatectomized CBA and C57BL mice, together with sheep's red cells, into lethally irradiated syngeneic mice showed that the CBA mice acquired the ability to increase the number of antibody-forming cells much sooner after the operation (4 h) than C57BL mice (17 h). Transplantation of the lymphocytes in a semisyngeneic system led, as a result of the graft versus host reaction (GVHR), to a decrease in the number of antibody-forming cells during subsequent immunization of the recipients with sheep's red cells. The GVHR was less severe in the hepatectomized mice than in the controls. These changes also appeared sooner after the operation in CBA mice than in C57BL mice.

Repeated amputation of the lower incisors in rats during early postnatal development induces enlargement of the salivary glands and hypertrophy of the testes, accompanied by their more rapid differentiation. Testicular hypertrophy following this procedure is much more marked (76%) than after unilateral castration at the same age. Although repeated amputation of the lower incisors in adult animals is followed by hypertrophy of the salivary glands, it does not cause hypertrophy of the testes.

Repeated amputation of the lower incisors in rats aged 11 and 14 days causes hypertrophy of the testes only if the submandibular salivary glands are present. Bilateral removal of the submandibular and sublingual salivary glands prevents the development of testicular hypertrophy. After unilateral removal of these glands the testis increased in weight but hypertrophy did not always develop. The absence of testicular hypertrophy in the sialadenectomized animals is evidence that the growth-stimulating action of repeated amputations of the lower incisors on the testis is mediated somehow through salivary gland function.

After unilateral removal or burns of a single submaxillary salivary gland and also after amputation of the lower incisors in CBA mice the ability of the spleen cells to form antibodies and to take part in the graft versus host reaction was studied and the number of hematopoietic stem cells was counted by the splenic colonies method. Each of the experimental procedures on the salivary glands was shown to be accompanied by increased migration of stem cells, and the ability of the lymphocytes to induce a graft versus host reaction was increased. The ability of splenic lymphocytes to react to an additional antigenic stimulus is enhanced by amputation of the lower incisors, which was followed by enlargement of the salivary glands, and is sharply reduced by removal or burns of the submaxillary salivary gland, neither of which induces hypertrophy of the salivary glands.

T-lymphocytes from the spleen of partially hepatectomized CBA mice enhance the mitotic activity of hepatocytes and Kupffer cells of the liver in nonoperated recipients. The proliferation induced by these cells is equal to the inductive capacity of the whole suspension of lymphocytes from the spleen of partially hepatectomized animals, which contain T- and B-lymphocytes. The proliferation induced by B-lymphocytes from the spleen of operated mice is significantly lowered and is displayed chiefly in relation to Kupffer cells.