Kunihiko Morita

Natural Killer Cell Activity in Mice after Intraperitoneal Administration of Beryllium Chloride

Natural killer (NK) cells are cytotoxic lymphocytes that are present in the blood, spleen, lymph nodes and abdominal cavity of humans and animals. There are asialo GM1 antigens as well as many other antigens on the surfaces of their membranes, particularly in mice. As NK cells are supposed to play an important role in protecting the living body against the development of tumors and viral infections, they are regarded as one of the immunological parameters for the defense mechanism of the body. Beryllium (Be) is reported to be carcinogenic to humans and animals. The carcinogenic mechanisms of Be, however, have not yet been studied in relation to NK cell activities. The aim of this study is to examine the influence of Be on NK cells to seek a clue to the carcinogenic mechanisms of Be.

Immune Response in Guinea Pigs Injected with Insoluble Beryllium Compounds

Immune Response in Guinea Pigs Injected with Insoluble Beryllium Compounds: Tsutomu Yoshida, et al. Department of Public Health, Fujita Health University School of Medicine—The changes in immune response of guinea pigs intrapleurally injected once with beryllium oxide (BeO) or beryllium copper alloy (Be‐Cu) were examined. To evaluate the changes in immune response of guinea pigs, two indicators, beryllium lymphocyte transformation test (Be‐LTT) and complement hemolytic activity (CH50), were used. The BeO or Be‐Cu injection groups was divided three groups, a high concentration injection group (36 μg Be dose), a low concentration injection group (3.6 jug Be dose) and the control group. The Be‐LTT and CH50 were determined in the blood of guinea pigs at 4, 8 and 16 weeks after Be administration. The Be‐LTT value at the 4th week in the BeO groups (a high or low concentration injection group, respectively) showed a statistically significant increase (p <0.01) compared with that of the control. In the Be‐LTT value for BeO at 8 and 1 6 weeks after Be injection and the Be‐Cu groups, there were no statistical difference between the Be administration groups and the control. On the other hand, only the CH50 of the high concentration group at the 8th week in the BeO injection group was significantly decreased (p <0.01) compared with that of the control. In the other Be injection group, no significant changes in the CH50 was observed compared with the control group. On the basis of the results observed in the present study, there may be a slight difference in the effect on the immune response of guinea pigs caused by BeO or Be‐Cu administration. The immunotoxicity of Be in guinea pigs may manifest itself more intensely in the cellular immune response than in the humoral immune response.

The influence of beryllium on cell survival rates in theIn-vitro culture system, on intracellular DNA synthesis and on SRBC-IgM antibody production responses

Immunocytotoxicity of beryllium (Be) was evaluated by studying cell viability, intracellular DNA synthesis and SRBC-IgM response in an in-vitro culture system using non-sensitized spleen cells of a C57BL mouse. Be addition showed a suppressive effect on cell viability, an enhancing effect on DNA synthesis and on IgM antibody production. The suppressive effect on cell viability manifested itself markedly as the concentration of Be was increased or the culture time was prolonged. The DNA synthesis-enhancing effect was noted at a relatively low concentration of Be (not more than 10μM). The enhancing effect on the IgM response was related to Be concentration at not more than 20μM. The experimental results mentioned above speculate that the cytotoxicity of Be shows a conflicting pattern of enhancement or suppression according to the concentration used and that immunologically it has a modulating effect or an activating effect on the immunocompetent cells.