[Proliferative and differentiation properties of bone marrow hematopoietic stem cells in CBA mice of various ages]. / Proliferativnye i differentsirovochnye svoistva stvolovykh krovetvornykh kletok kostnogo mozga u myshei linii CBA razlichnogo vozrasta.

Hemopoietic bone marrow stem cells (CFCs) of young (3-5 months) and old (23-24 months) were studied according to their ability to form colonies in spleens of the lethally irradiated animals. The number, morphology and volume of CFCs were microscopically examined. The content of CFCs remained unchanged during aging. The number of erythroid colonies decreased in old mice, while that of granulocyte-macrophage and mixed colonies did not change. The megakaryocyte colonies showed even an increase with age. Volumes of all the colony types, except megakaryocyte, reduced. The results obtained thus reflect some age-related features of early stages of the stem-cell differentiation.

Stromal hemopoietic microenvironment in aging.

The bone marrow content, proliferative potential and proliferative activity of precursor cells for stromal fibroblast colony forming cells (CFC-F) were investigated in young and old CBA mice. The relationship between CFC-F and the number of bone marrow nucleated cells and granulocytic-macrophagal precursors (GM-CFC) was studied as well. The results obtained showed increased CFC-F contents in old animals. The proliferative potential of old mice CFC-F did not appear to differ from that of young animals. The proliferative activity of bone marrow CFC-F and hemopoietic stem cells--spleen colony forming cells (CFC-S) was studied by determining the sensitivity to hydroxyurea administration. The responses were almost the same in young and old mice. A direct correlation between CFC-F and nucleated cells and GM-CFC precursors was found in young mice, but not in the old animals. The results of the present study have pointed to the reorganisation of the stromal tissue microenvironment in bone marrow in old age.

Functional rearrangement of lymphohemopoietic system in heterochronically parabiosed mice.

This study examines some characteristics of the lymphohaemopoietic system of heterochronically parabiosed CBA mice. It was found that a decline of the primary immune response in a young mouse sutured with an old one is accompanied with the diminution of: bone marrow and thymus cellularity; thymus weight; haemopoietic stem cells (CFC-S) and granulocyte-macrophage precursor cells (CFC-C) contents in the femur, and stromal precursor cell (CFC-F) contents both in the femur and thymus. All the indices tested, including the immune response level, in old parabionts vs. old single mice remained unchanged. In the spleen, the considerable variations of splenic weights in the mice of different control and experimental groups have been found. At the same time, no significant changes in the cellularity and CFC-F number in the spleen of all examined groups of animals have been observed. The findings strongly indicate the considerable rearrangement of lymphohaemopoietic and stromal tissues in the central organs of the immune system, namely, bone marrow and thymus of young mice due to the parabiosis with old ones.

[Comparative immunological and electron microscopic study of the structure of E-RFC and OKT-3+ lymphocytes from human blood]. / Sravnitel'noe immunoélektronno-mikroskopicheskoe issledovanie stroeniia E-ROK i OKT-3+ limfotsitov krovi cheloveka.

Methods of immune electrone microscopy have revealed that OKT-3+ cells and E-RFC of human blood have a similar ultrastructure. Definite morphologic spectrum is observed within each of these fractions, that testifies to the heterogeneity of surface markers of circulating T-lymphocytes and their ultrastructure.

[Effect of hydroxyurea on the number of hematopoietic stem cells, stromal cell precursors and cell precursors of thymus lymphoid tissue in the bone marrow of mice during aging]. / Vliianie oksimocheviny na soderzhanie stvolovykh krovetvornykh kletok, stromal'nykh kletok-predshestvennikobv i kletok-predshestvennikov dlia limfoidnoi tkani timusa v kostnom mozge myshei pri starenii.

The concentration of hemopoietic stem cells (colony-forming cells in the spleen - CFC-S) decreases in the bone marrow of CBA mice during ageing, whereas the concentration of precursors for stromal fibroblasts (colony-forming cells for fibroblasts-CFC-F) increases. The total numbers of nucleated cells, CFC-S and CFC-F in the bone marrow of old mice essentially increase. Hydroxyurea, administered in vivo, does not effect the concentration of CFC-S, but it increases CFC-F concentration in the bone marrow of mice. Hydroxyurea produces just the same suppressive effect on the numbers of nucleated cells, CFC-S and CFC-F in the mice of different ages, and stimulates the capacity of bone marrow donors to repopulate the thymus of the irradiated young recipients.

[Experimental investigation on possibilities of regeneration of the immunity in old animals (author's transl)]. / Experimentelle Untersuchungen der Reparationsmöglichkeit der Immunität bei alten Tieren.

The effect of Levamisol, potassium polyadenylate, complete Freund's adjuvant and "antigen premunition" on the primary and secondary immunological response to sheep erythrocytes as well as the reaction of "graft versus host" were tested on mice of the CBA strain belonging to various age groups. The greatest stimulation effect in both types of response, i.e. humoral and cellular, was produced by "premunition". Levasimole clearly increased the reaction of "graft versus host", while the humoral response was weakened. The application of potassium polyadenylate produced a weaker stimulus to the response to sheep erythrocytes, and it was not effective in the response of "graft versus host". The complete Freund's adjuvant had no influence whatsover on the humoral immune response in old mice.

[Age and features of the suppressor activity of antigen primed spleen cells of CBA strain mice and regulation of the immune response in old age]. / Vozrastnye osobennosti supressornoi aktivnosti primirovannykh antigenom kletok selezenki myshei linii CBA i reguliatsiia immunnogo otveta v starosti.

A study of primary immunological response to the ram erythrocytes and response of primed CBA mice of different age has shown a sharp fall of the primary immunological response in senility. The young animals responded to the priming by the decrease of formation of direct antibody-forming cells in the spleen what is connected with the activation of suppressor cells. The response of primed animals increased with the age and attained in old mice the values markedly exceeding that of primary immunological response. In the system of syngeneic adoptive transfer of the spleen cells from the primed mice of different age, the response of recipients of young animal's cells was lower that of recipients of old animal's cells. The data obtained suggest the devrease of the suppressor activity of the primed spleen cells with the age.