Antibody levels in reduced/alkylated intravenous immune globulin.

Antibody titers, found in representative lots of a reduced and alkylated intravenous immune globulin, against a variety of common microorganisms are presented. With the more frequently occurring pathogens the specific antibody level does not vary significantly between lots. Depending upon the type of assay used, antibody titers per se may or may not reflect the therapeutic activity of the preparation against a specific microorganism.

Anticardiolipin antibodies and thrombosis: buffer's influence on the detection and quantitation of anticardiolipin antibody measured by ELISA.

The influence of adult bovine serum (ABS) and fetal calf serum (FCS) on IgG anticardiolipin antibodies (ACA) levels measured by ELISA has been investigated. In control subjects the frequency of the optical density (O.D.) distribution was found to be non-gaussian. The O.D. of the 97th percentile was similar with both buffers, although the distribution of O.D. was statistically different (P less than 0.004). The slope of the dilution curves of two house standards as well as the curves obtained with reference standards were found to be very different depending on the buffer. In 55 consecutive patients with thrombotic events, recurrent fetal loss or auto-immune disorders, ACA positivity was also dependent on the way to express the data and the choice of the buffer: when O.D. values were read with their respective standard curves, IgG ACA positivity was 98% with FCS and 20% with ABS (P less than 0.001), but when the 97th percentile O.D. was considered, 40% were positive with FCS and 51% with ABS (n.s.). Furthermore 10 patients were found to be negative with FCS and positive with ABS and 4 others showed the inverse picture. Levels of positivity were also dependent on the buffer. These differences arise from the solution used to dilute the sera and not of that to block the plates. These methodological problems may explain some conflicting data found in the literature about the prevalence of ACA positivity.

[The systematization of the enzyme-linked immunosorbent assay (=ELISA)]. / Ein Beitrag zur Systematisierung des Enzyme-Linked-Immuno Sorbent Assays (= ELISA).

Using the example of the detectability of immunological methods the study shows the considerable influence exerted by this detectability on the quantitative and qualitative parameters and the necessity of a systematization of the methods. This systematization already starts with the product labeling: A sufficient description of antibodies has to contain five qualities. The profitability of the experimental research is improved by optimized product and method systematization. ELISA is presented in a systematized form as a modular system optimizing the comparability of these methods. In order to detect the gain of information transparency obtained by systematization, an ELISA, described in the literature, is presented in the original and in the systematized form.

A comparison of polyclonal antisera to pregnanediol 3 alpha glucuronide obtained from three different rabbits and their use in ELISA.

The variation in the estimates of urinary pregnanediol glucuronide obtained by ELISA with 12 polyclonal antisera has been assessed. Of the 12 antisera, eight gave values comparable with each other and could be used interchangeably in the ELISA. Thus a large stock of polyclonal antibody which gave consistent values was generated and can now be used in diagnostic ELISA over a long period of time. This procedure is more economical than the development of monoclonal antibodies for the same purpose.

Four immunoassay methods and standards compared for measuring fibronectin.

Several companies have developed commercial kits to measure plasma fibronectin rapidly and inexpensively with readily available laboratory equipment. In two of these kits (Cooper Biomedical and Boehringer-Mannheim) an immunoturbidimetric method is used. In a third kit (Biomedical Technologies, Inc.) an enzyme immunoassay method is used. To evaluate these commercial kits for fibronectin assay, we selected nephelometry as a comparison method for ranking the kits with regard to precision and accuracy. We also compared antibody and fibronectin cross reactivity. The antibodies from various manufacturers appear similar, but the fibronectin standards from different sources showed significant variation. Rate nephelometry and the Boehringer-Mannheim kit had the best within-run precision (CVs of 0.38% and 5.5% respectively). Between-run precision for nephelometry was excellent (CV = 1.9%) and somewhat high for the Boehringer-Mannheim kit (CV = 15.4%). This study demonstrates a need for further standardization of antigen (fibronectin) and antibody in commercial kits and the development of suitable stable quality-control material.

Reduction of animal usage: British Pharmacopoeia Commission policy.

The British Pharmacopoeia Commission is committed to working towards the replacement or modification, wherever possible, of those assays and tests of the Pharmacopoeia that are performed in vivo and which may involve pain. An alternative or modified method is adopted by the Commission once it has been clearly demonstrated that it offers satisfactory control for pharmacopoeial purposes of the potency or other specific property of the preparation concerned. The relevant monographs of the British Pharmacopoeia and of the British Pharmacopoeia (Veterinary) are kept under active review and number of lines of investigation are being pursued by the appropriate advisory committees in furtherance of the Commission's objective. In vivo techniques are currently required for two main purposes, safety and potency testing of a range of biological materials. The progress being made towards a reduction in animal usage for safety purposes is exemplified by work being carried out with the aim of reducing reliance on rabbit testing for pyrogens. It is expected that the use of HPLC for the assay of peptide hormones may permit the phasing out of certain bioassays. With respect to immunological products several lines of enquiry are being followed. While in vitro alternatives remain the long term objective, the modification of existing in vivo methods to permit non-lethal end-points and the possibility of using analgesics are also considered. In pursuing this policy the Commission actively encourages those associated with its work to seek alternative procedures but it must be understood that the Commission itself has no source of funds to finance the necessary research.(ABSTRACT TRUNCATED AT 250 WORDS)

External quality assurance and assessment in immunocytochemistry.

A quality assurance scheme for immunocytochemistry was started in 1984. There are currently 140 participating laboratories, most of which have shown considerable improvement in their results since joining the scheme. In our experience the supplier of the primary antibody does not affect the quality of the results; the sensitivity of the method used and the experience of the staff carrying out the technique are the most important factors. Participation in a scheme such as this enables laboratories to have their results compared with others and to share problems.