WHO Reference Reagent Research Articles

The ISOBM TD-7 Workshop on hCG and Related Molecules

The ISOBM TD-7 hCG Workshop was established to characterize the molecular epitope structure and specificities of a panel of diagnostically relevant monoclonal antibodies (MAbs) directed against human chorionic gonadotropin (hCG) and its derivatives, and to consider how this information could be used to improve comparability of immunoassay results for these analytes. In this multicenter study, 27 MAbs have been characterized in detail as to their main and fine specificities by direct binding-, competitive- and sandwich-RIA, -ELISA, BIAcore^® and Western blotting. Antigens used in the study included the upcoming first WHO reference reagents for immunoassay, i.e. nick-free hCG (hCG), nicked hCG (hCGn), hCG α-subunit (hCGα), hCG β-subunit (hCGβ), nicked hCG β-subunit (hCGβn), hCG β-core fragment (hCGβcf), synthetic peptides of hCGβ C-terminal peptide (hCGβCTP), and homologous hormones, luteinizing hormone (LH) and subunits (LHβ) from various species. Correct classification of blinded internal controls demonstrated the reliability of the MAb referencing approach. Three-dimensional molecular epitope assignment was possible in many instances by comparing immunoreactivity of the ISOBM MAbs (n = 27) to a large panel of MAbs (n = 18) previously well characterized in the Innsbruck (P.B.) and Paris (J.M.B.) laboratories. All three major antibody specificities (α, n = 1; β, n = 21; αβ, n = 5) were represented in the TD-7 MAb panel. HCGβ MAbs could further be subdivided into (i) those recognizing hCGβ only (epitopes: β₆, n = 1; β₇, n = 2; β₁₄, n = 1) and (ii) those recognizing hCGβ + hCG (β₁, β₂, β₄, β₅, n = 10; β₈ and β₉, n = 9). Members of the latter group were specific either for hCG + hCGβ + hCGβcf (β₁, n = 3) or hCG + hCGβ + hCGβCTP (β₈, n = 6; β₉, n = 1) or in addition to hCG + hCGβ + hCGβcf recognized hLH/hLHβ to a minor (β₂, n = 3; β₄, n = 3) or similar degree (β₅, n = 1). Epitopes were (i) located on the first and third loops protruding from the cystine knot of hCGβ (β₂–β₆, aa hCGβ20–25 and 68–77), (ii) presumably centered around the knot itself (β₁), or (iii) on hCGβCTP (epitope β₈ = hCGβ141–144, β₉ = hCGβ113–116). The ISOBM panel of MAbs represents all major epitope specificities suitable for the design of specific sandwich immunoassays. High analyte variability in serum and urine during the course of pregnancy and tumor development favors certain epitope combinations. For routine diagnostic purposes, assays recognizing a broad spectrum of hCG/hCGβ variants such as hCG + hCGn + hCGβ + hCGβn + hCGβcf + –CTPhCG + –CTPhCGβ may be useful. Low cross-reactivity against related glycoprotein hormones (e.g. hLH) and their derivatives is mandatory. These criteria are best met by combinations of MAbs directed against epitopes located around the cystine knot (β₁) and against those encompassing the top of loops 1 and 3 on hCGβ (β₂, β₄). The first WHO reference reagents for immunoassay of hCG and hCG-related molecules being prepared by the IFCC should facilitate characterization of what assays for ‘hCG’ are measuring. The next step towards improving between-laboratory comparability of measurements of hCG/hCG derivatives in pregnancy and oncology is provided by results of this TD-7 Workshop.

Comparison of Pituitary and Recombinant Human Thyroid-stimulating Hormone (rhTSH) in a Multicenter Collaborative Study: Establishment of the First World Health Organization Reference Reagent for rhTSH

The increasing use of recombinant-DNA-derived materials in therapy and diagnosis poses a new challenge for biological standardization, that of developing reference preparations appropriate for both the native and recombinant products. Here we report the results of an international collaborative study that was carried out under the auspices of WHO to assess the suitability of a preparation of recombinant thyroid-stimulating hormone (rTSH; 94/674) to serve as a potential standard for the calibration of diagnostic immunoassays compared with the International Reference Preparation (IRP) for human TSH (80/558). Coded samples were provided to the 33 laboratories in the study, and participants were asked to perform TSH assays currently in use in their laboratories. Twenty-eight laboratories contributed 93 immunoassays in 41 different method-laboratory combinations, and an additional 5 laboratories contributed bioassay data. All data were analyzed centrally at the National Institute for Biological Standards and Control. The results obtained in different laboratories and with different assay systems revealed significant variability between estimates of rTSH relative to the IRP. These ranged from 5. 51 mIU (95% limits, 3.95-7.67 mIU) per ampoule by RIA to 7.15 mIU (95% limits, 6.7-7.63 mIU) per ampoule by immunofluorometric assay. However, the results showed that the assignment of a value of 6.70 mIU per ampoule of 94/674 would give reasonable continuity with the IRP in many assay systems. The preparation was established as the First WHO Reference Reagent for TSH, human, recombinant, to provide a means of validating assay performance and to maintain continuity with the IRP without compromising clinical data.

NIH/NIAID‐WHO AIDS Research and Reference Reagent Program

Annals of the New York Academy of SciencesVolume 616, Issue 1 p. 610-610 NIH/NIAID-WHO AIDS Research and Reference Reagent Program S. STERN, Corresponding Author S. STERN Pathogenesis Branch AIDS Program NIAID, NIH Rockville, Maryland 20850Pathogenesis Branch, AIDS Program, NIAID, NIH, 649A Lofstrand Lane, Rockville, MD 20850.Search for more papers by this authorL. MUUL, L. MUUL Pathogenesis Branch AIDS Program NIAID, NIH Rockville, Maryland 20850Search for more papers by this authorG. MILMAN, G. MILMAN Pathogenesis Branch AIDS Program NIAID, NIH Rockville, Maryland 20850Search for more papers by this author S. STERN, Corresponding Author S. STERN Pathogenesis Branch AIDS Program NIAID, NIH Rockville, Maryland 20850Pathogenesis Branch, AIDS Program, NIAID, NIH, 649A Lofstrand Lane, Rockville, MD 20850.Search for more papers by this authorL. MUUL, L. MUUL Pathogenesis Branch AIDS Program NIAID, NIH Rockville, Maryland 20850Search for more papers by this authorG. MILMAN, G. MILMAN Pathogenesis Branch AIDS Program NIAID, NIH Rockville, Maryland 20850Search for more papers by this author First published: December 1990 https://doi.org/10.1111/j.1749-6632.1990.tb17906.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume616, Issue1AIDS: Anti-HIV Agents, Therapies, and VaccinesDecember 1990Pages 610-610 RelatedInformation

Standards for ANA and anti-DNA

A review of the history, production, characterics and availability of the standards and reference preparations in the field of ANA determination is given. For ANA of the homogeneous type and for anti-DNA standard reagents are recognized by the WHO. This enables the expression of quantitative results in international units, leading to a decrease of interlaboratory variations. For the other types of nuclear fluorescence and for anti-Sm, anti-Ro (SS-A), anti-La (SS-B), anti-Scl 70 and anti-Jo-1, reference reagents are made available by the Arthritis Foundation (AF) and the Centers for Disease Control (CDC) in the USA. For anti-nRNP, a WHO reference reagent exists. The use of the above materials is advocated. Requests for WHO standards should be directed to: Dept. of Reagents CLB, P.O. Box 9190, 1006 AD Amsterdam, The Netherlands, and for AF/CDC reagents to: AF/CDC ANA Ref. Lab., Immunology 1 - 1202 A 25, CDC, Atlanta GA 30333, USA.