Effects of in utero exposure to cyclophosphamide in mice. I. Pregnancy outcome and observations of offspring during early postnatal life.

Swiss-Webster mice treated orally with cyclophosphamide (Cy) (1, 2.5 or 5 mg/kg) once daily on gestational days 6 through 18 gave birth to pups which appeared to be normal and the majority of which survived to adulthood. The maternal treatment resulted in reduced mean pup weight at birth and increased cumulative pup mortality. On the other hand, pregnancy outcome and mean pup body, spleen and thymus weights, when measured at 4 weeks of age, were within the control ranges. Similarly, hematological profiles, serum immunoglobulin (IgG, IgM) levels and histology of the lymphoid tissue (spleen and thymus), assessed at 4 weeks of age, were not affected by the maternal treatment. Treatment with 7.5 mg/kg Cy not only resulted in reduced litter size but also increased the cumulative pup mortality. In addition, with this dose, histopathological changes were observed in the thymus in 2-and 3-week old pups. The morphology of the thymus in 4-week old pups was unremarkable. At the dose of 10 mg/kg no live births were recorded.

Effects of rifampin treatment on contact sensitivity reactions to oxazolone in Balb/C mice.

Treatment of mice with rifampin (Ri, 100-200 mg/kg) affected the course of contact sensitivity (CS) reactions to oxazolone. The effects which were seen as either partial inhibition or enhancement of the response, under one set of conditions, could be abrogated or even reversed if conditions of either induction, elicitation and time of measuring reactions were altered. In addition, amount of Ri used for treatment and time of treatment in relation to the induction of CS reactions also influenced the effects observed.

Effects of in utero exposure to cyclophosphamide in mice. II. Assessment of immunocompetence of offspring from 5 to 10 weeks of age.

Offspring of mice treated with cyclophosphamide (Cy; 1, 2.5 or 5 mg/kg) during pregnancy (6-18 days of gestation) and tested for immunocompetence from 5 to 10 weeks of age were found to have defective reticuloendothelial clearance. The main effects were: a) increased elimination half time (T 1/2) of 51Cr-labeled SRBC from circulation, b) decreased liver uptake of 51Cr and c) impaired ability of the spleen, mostly affecting the female pups, to compensate for decreased liver uptake. The highest dose group suffered the most pronounced effects. This group was also found to have increased IgG immunoglobulin levels at 7 weeks of age. IgG antibody production in response to specific antigenic stimulation and delayed hypersensitivity reactions to oxazolone did not appear to be affected by Cy treatment.

Preparation and immunological properties of procaine-protein conjugates.

Procaine was conjugated to BSA and rat and rabbit Gf using the carbodiimide method and 14C-procaine as a tracer. The composition of the conjugates could be varied depending on the time of incubation and the concentration of procaine in the reaction mixture. Procaine-BSA conjugates were soluble in water or saline. However, procaine conjugates to rat or rabbit Gf were not readily soluble in saline. These conjugates were good for immunization purposes, but it was cumbersome to work with them when clear solutions were needed, as in the immunochemical procedures used in this study. The immunological properties of the conjugates were studied in rats and rabbits. Rats responded with production of IgGa and precipitating antibodies to the procaine group, but IgE antibodies to the immunogen could not be detected. Furthermore, precipitating antibodies towards the procaine group were raised in rabbits. When BSA was the protein carrier, antibodies to the carrier molecule were also detected in both rats and rabbits. The conjugates of procaine to rat or rabbit Gf did not elicit antibody response to the carrier molecular when used in the homologous species. Hapten inhibition studies suggested that, in the rabbit, antibodies were also produced with specificity directed towards the molecular configuration of the hapten-carrier bond.

Immunological properties of dialysis retentates from penicillin.

Retentates from benzylpenicillin preparations marketed in Canada were used in immunological studies in order to determine if they were immunogenic in experimental animals with respect to anaphylactic antibody production. The retentates obtained consisted mainly of penicillin polymers. Impurities of protein nature were either insignificant or absent. The penicillin polymers were found to be non-immunogenic in Albino Wistar rats, Wistar Furth rats and Hartley guinea pigs. Furthermore, they were unable to effect positive PCA tests in rats passively sensitized to the penicilloyl determinant.

Production of rat homocytotropic antibodies using low dose, long term oral exposure to penicillin G.

Sera from 15 patients with immediate hypersensitivity reactions to penicillin G gave positive responses in the rat mast cell test (RMCT) indicating the presence of IgE-type antibodies in the sera. Five sera were from patients who had had reactions to penicillin 15 to 22 years previously without known re-exposure to this antigen. To explore the possibility that non-therapeutic exposure to penicillin may have produced continued sensitization in these patients, an animal model system was developed to explore the efficacy of low dose, long term oral exposure to penicillin G in rats for producing homocytotropic antibodies in these animals. It was found that when rats were given penicillin G in their drinking water at concentrations of 0.1 to 1 U/ml over a period of 1 to 3 months they produced serum IgE and IgGa antibodies. In addition, IgE antibodies were actively bound to the peritoneal mast cells of these animals. The presence of circulating or cell bound antibodies was detected using the rat mast cell test. It was also shown that rats given penicillin G orally for 1 month were more prone to antibody production after a single intramuscular injection of penicillin G compared to a control group receiving only the intramuscular injection of this antigen. The results of this study are discussed in terms of possible non-therapeutic sensitization towards penicillin G in the human population.

Production of anaphylactic antibodies to drugs in experimental animals. I. Benzylpenicillin.

Studies were undertaken to determine if animals exposed to benzylpenicillin could produce anaphylactic antibodies to the drug moiety. For this purpose, Albino Wistar rats were divided into four groups. Two groups of animals were immunized with benzylpenicillin using either the intraperitoneal or the subcutaneous route. The remaining two groups were used for feeding experiments. The animals were bled upon termination of the experiments; their sera were collected and pooled per group. The pooled sera were tested for the presence of anaphylactic antibodies. Histamine release from rat mast cells under the appropriate conditions was used as an indicator of antibody production. Penicilloylpolylysine and benzylpenicillin were both employed to determine antibody specificity. It was found that sera from all groups of animals contained anaphylactic antibodies with specificity towards the penicilloyl group and "benzylpenicillin".