Lenses of rabbits with high titers of homologous lens antibodies showed no lesions, even after repeated paracentesis of the anterior chamber in a number of such animals. In these instances, lens antibodies were shown to be present in both the primary and secondary aqueous humors. A small group of rabbits with high homologous anti-lens antibody titers were successfully bred. These had been immunized with adult rabbit lens pools in Freund's adjuvants, and had high antibody levels throughout pregnancy. No significant congenital lens lesions were found when these 18 young from 3 litters were compared with the 17 young from 3 litters of mothers who had no detectable anti-lens antibody through gestation. The latter group of does had received the equivalent doses of homologous lens in saline. Patients with cataract did not show demonstrable anti-lens antibodies in their serum when tested by the agar precipitin technic against cataractous human lens homogenates.
A quantitative and standardized enzyme-linked immunosorbent assay is described which uses lyophilized antigen-coated disks for the detection of human antibodies to Toxoplasma gondii. It does not require serial dilution of the test specimen, and the objective absorbance readings are converted into international units per milliliter traceable to the World Health Organization's reference standard preparation of toxoplasma antibodies. It was shown to be highly specific, reproducible, and sensitive. The reagents were stable, without biohazard, and ready for use. Studies of various parameters in the assay indicated that the test conditions were relatively flexible. The enzyme-linked immunosorbent assay results correlated satisfactorily with the methylene blue dye test, the indirect immunofluorescence test, and the passive hemagglutination test.
As in the human, the rat pregnancy-associated plasma proteins consisted of four distinct entities as revealed by immunological methods. All showed gradual increases during gestation and rapid disappearance postpartum. They could be physicochemically, although not immunologically, tentatively related to the human pregnancy proteins. None of them was detectable in the serum of rats at various stages of pseudopregnancy, nor in nonpregnant rats.
Summary At term, the pregnancy‐associated plasma protein B (PAPP‐B) level in normal pregnancy was correlated with placental and newborn weights, but not with nine other normal obstetric variables. It was lower in pregnancies complicated by diabetes or severe toxaemia, and higher in twin pregnancies.
Although a very good correlation was found between the level of rubella antibodies measured by a standard hemagglutination inhibition (HI) test and by an enzyme-linked immunosorbent assay (ELISA) procedure (Cordia R), an appreciable proportion (31%) of ELISA-positive specimens were encountered among HI-negative sera. The reverse was rarely seen. Many of the HI-negative, ELISA-positive sera were also found to be positive for rubella antibodies by one or more other assay methods, including an immunofluorescence assay (IFA) procedure (FIAX), passive hemagglutination (PHA) (Rubacell and PHAST), latex agglutination (Rubascan), and a second ELISA procedure (Rubelisa). The specificity of all of the ELISA-positive HI-negative specimens was substantiated by absorption experiments. In these tests, the ELISA reactivities were blocked by rubella antigens, but not by a variety of tissue culture control antigens or by influenza virus grown on the same cell line. The findings indicate that many of the newer methods available for rubella antibody detection are more sensitive than HI for detecting low levels of rubella antibodies. Until more clinical information is available concerning the protective nature of these low levels of antibody, caution should be exercised in assessing the significance of these results.
