Limitations of the Nonhuman Pregnancy Kit for Pregnancy Diagnosis in Baboons

Noninstrumented enzyme-linked immunosorbant assay for detection of early pregnancy in macaques

A practical, noninstrumented enzyme-linked immunosorbant assay (NELISA) for the measurement of urinary monkey chorionic gonadotropin (mCG) has been developed for the detection of early pregnancy in macaque monkeys for use in both the laboratory and the field. Five rhesus monkeys (Macaca mulatta) and six crab-eating monkeys (Macaca fascicularis) were tested for the presence of mCG in urine on gestational days (GDs) 12 to 35. The mCG NELISA detected pregnancy as early as GD 14, with an average earliest detection at GD 16.5 +/- 1.4 (n = 11). Out of 90 tests, 27 false-negative and zero false-positive tests were obtained, for an accuracy of 70.0%. Without the aid of a spectrophotometer, the presence of mCG in pregnant monkey samples was indicated by a dark green color change. Nonpregnant monkey urine samples, on the other hand, exhibited no color change. These findings suggest that the simple, economical, and reliable urinary mCG NELISA may be useful for diagnosing early pregnancy in these and related species. Because capture and restraint are unnecessary for collecting urine samples, the mCG NELISA has widespread potential for confined and free-ranging animals.

Effects of baboon chorionic gonadotrophin antibodies on placental derived baboon trophoblast cells in vitro

Immunization against chorionic gonadotrophin (CG) can terminate pregnancy in a number of species but the mechanisms responsible for this are poorly understood. Baboon CG has recently been purified and antibodies against this molecule were used in an in vitro system to study their effects on cultured trophoblast cells derived from placentae at 33 days of gestation. Secretion of bCG was measured by radioimmunoassay and the origin of this material was studied using immunohistochemical procedures. Heterologous antibodies against CG were introduced on day 5 of culture. Trophoblast cells appeared to secrete a CG material which was detectable in the daily spent medium and was localized within the trophoblast cells. Addition of antibodies caused cell lysis which was complement dependent. It was concluded that CG was localized on the baboon trophoblast cells and that antibodies against bCG caused complement dependent cell lysis.