Antibody production stimulating activity of bone marrow cells from tolerant rats.

The antibody production stimulating activity of BM cells from SRBC-tolerant and normal rats were studied. Tolerance was induced by repeated injections of SRBC which were begun within 24 h after birth. BM cells obtained from tolerant animals 14-24 days after the last SRBC injection or from normal rats of the same age were used.

Cell interactions at the level of mature antibody producers: the properties of the bone marrow humoral factor stimulating antibody production.

The soluble factor recovered from supernatants of cultures of normal mouse bone marrow cells and previously isolated on Sephadex G-50 (n. w. 13,000 daltons), which stimulates antibody production when given at the peak of immune response, was further characterized in the present study.

[Comparative study of the intermittent and continuous action of the herbicide, Ramrod].

Repeated oral toxicity was assayed in albino rats of either sex, receiving every day 70 mg/kg of Ramrod for 4 months (group I) and everyday, but on alternate weeks-140 mg/kg (group II). A third experimental group of animals received daily 70 mg/kg of Ramrod on alternate weeks for 8 months. In comparison with the respective pure control groups of rats, those receiving monotonous treatment has the most liver function changes.

[Assessment of the chronic toxic action of the herbicide, balagrin, in continuous and intermittent exposure regimens].

Chronic oral toxicity of the herbicide balagrin, a selective and perspective preparation for rural economy, was experimentally studied on 258 Wistar albino rats. Two treatment schedules using the combined trade product (20 percent balan and 80 percent xylol) were assayed: montonous - 1/20 LD50 balagrin (55 mg/kg) and 1/20 LD50 xylol (235 mg/kg), administered every day and every week for 4 months; intermittent - 4 months' every day application on alternate weeks of 1/10 LD50 balagrin (110 mg/kg) and 1/10 LD50 xylol (470 mg/kg) and 8 weeks' application by the same schedule of 1/20 LD50 balagrin and 1/20 LD50 xylol. The results of clinico-laboratory, biochemical and functional investigations showed that the toxic effect was more pronounced with monotonous administrations of the compound.

[General toxicity and specific action of the herbicide balagrin].

The influence of the herbicide balagrin on the maternal organism and fetus was experimentally studied on 60 pregnant albino rats of Wistar line. The preparation was given orally throughout the entire gestation period in daily doses of 1/1o - 110 mg/kg, 1/20 - 55 mg/kg and 1/50 - 22 mg/kg of LD50 - 1100 mg/kg. The detoxifying function was studied by the duration of hexabarbital sleep, the excretory function - by the cholic acid content in the bile, and the enzymatic function - by the dehydrogenase activities: LDH, MDH, LDH, GL-6-PDH in the liver of pregnant animals and the fetus, Marked toxic effect on the maternal and fetal organism was demonstrable at all balagrin application levels by the liver function disturbances.

Xenogeneic bone marrow stimulating effect in vitro on antibody-producing cells.

It was described earlier that in the tissue cultures of immune mouse LN cells the number of antibody producing cells was increased 2-3-fold when syngeneic of allogeneic nonimmune BM cells were included in the cultures. In these experiments, parallel mixed cultures were set up of mouse immune LN cells with non-immune BM cells of either syngeneic or xenogeneic origin (rat, pig and chicken). Xenogeneic BM also increased the number of PFC in the mixed cultures.

[Nature of the humoral factor from bone marrow stimulating antibody production].

An active factor doubling the antibody synthesis in the culture of immune lymph node cells was isolated from the supernatant of the cultures of bone marrow cells from intact donors. Gel chromatography was used for this purpose. The stimulant of antibody producers (SAP) was eluated at the site of cytochrome C exit; the factor is heat-stable and has the mol wt of 1300 daltons.

[Effect of stimulating antibody formation under the influence of bone marrow cells in vivo].

Injection of intact bone marrow cells to mice at the peak of the secondary immune response results in a 2.4-fold increase of the number of antibody-forming cells in the regional lymph node. Preliminary injection of bone marrow cells to donors of the immune lymph node cells decreases the stimulation effect of antibody formation when the lymph node cells are subsequently cultivated with the intact bone marrow cells.

Cellular cooperation at the level of antibody-producing cells in chickens.

The effect of in vitro cocultivation of immune and non-immune syngeneic lymphoid cells on the antibody response was studied in chickens. Cocultivation of immune and non-immune spleen cells did not affect significantly the PFC numbers. Substantial increase in PFC was observed in mixed cultures of immune spleen cells with non-immune bone marrow cells.

[Role of different types of cells in the effect of immunoglobulin synthesis stimulation in mixed cultures].

The radioisotopic method with the use of immunosorbents was applied to the study of the synthesis of antibodies and nonspecific immunoglobulins in the mono- and mixed cultures of cells of the immune lymph nodes and intact bone marrow in removal of the adherent or T-cells. Treatment of the lymph node cell population with anti-O-serum decreased the antibody synthesis to 30%, whereas removal of the adherent cells - to 70%. In combined cultivation of the cells of immune lymph nodes, devoid of adherent cells, with the intact bone marrow cells the effect of stimulation of immunoglobulin synthesis was not eliminated, whereas treatment of cells of the immune lymph nodes with anti-O-serum doubled this effect.