Lack of Toxicological Effects Following Seven Years of Active Immunization of Rhesus Monkeys with the β-Subunit of Ovine Luteinizing Hormone

Abstract

Imnunization of rhesus monkeys against the β-subunit of ovine luteinizing hormone (oLHβ) reduced fertility but did not prevent ovulation or interrupt regular menstrual cycles. The mechanism(s) of antifertility action involves inpaired luteal function and/or failure of chorionic gonadotropin to stimulate the corpus luteum. Because of the significant cross reaction of the oLHβ-antibodies with serum LH and a moderate increase in circulating immune complexes, we investigated the effects of immunization on atherosclerotic lesions in ten monkeys which had been immunized for seven years and were fed a diet containing cholesterol (0.33 mg/kcal) during the last year. Ten non-immunized control monkeys were fed the same diet. The diet caused a significant increase in serum cholesterol levels in both groups of animals. Arterial characteristics such as plaque area, which can be used as indicators of the extent and/or severity of atherosclerosis, were measured in coronary and carotid arteries. Statistical analysis showed no significant differences between immunized and non-immunized groups, indicating that long-term immunization against pregnancy had no adverse effects on the extent and severity of atherosclerosis in hypercholesteremic monkeys.