A novel two-site immunoradiometric assay for β-endorphin using nitrocellulose as solid phase

Voellmy, D.; Külling, P.; Gramsch, Christian; Häni, M.; Mehraein, P.; Messiha, F.S.; Pasi, Aurelio

doi:10.1016/s0149-7634(88)80042-3

Cited by 4 publications

(2 citation statements)

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“…The use of such a specific monoclonal antibody would avoid the spuriously high results for ß-endorphin in patients with high IgG levels. Recently Voellmy et al (19) reported a two-site immunoradiometric assay for human ß-endorphin using a polyclonal rabbit anti-ß-endorphin antibody and an 125 Ilabeled monoclonal mouse antibody 3-E7, which binds to the N-terminal region of ß-endorphin. If no IgG effect is demonstrated with this newly developed monoclonal antibody method, we can anticipate greater accuracy and reliability in the determination of ß-endorphin concentrations.…”

Section: Discussionmentioning

confidence: 99%

Interference of Immunoglobulins in the Radioimmunoassay of Human β-Endorphin

Hashimoto¹,

Miyabo²,

Nishibu³

et al. 1990

Clinical Chemistry and Laboratory Medicine

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Summary:The interference of immunoglobulins in the radioimmunoassay (RIA) of human ß-endorphin was investigated. Human IgM showed no cross-reactivity. Human IgA showed a weak cross-reaction, but the dilution curve of IgA did not show parallelism with the standard curve of ß-endorphin, thus indicating its antigenic difference. The dilution curves of human IgG showed 0.18% displacement with respect to the human ß-endorphin standard curve, with good parallelism. Moreover, five patients with multiple myeloma of the IgG type showed falsely elevated ß-endorphin levels. We investigated the possibility that certain IgGs may be responsible for the displacement of [ 125 I] ß-endorphin in the ß-endorphin kit. The apparent ß-endorphin level of plasma from multiple myeloma patients was markedly decreased after affinity chromatography of the serum on protein A-Sepharose.In another 3 patients with multiple myeloma, we examined IgG interference by measuring the ß-endorphin levels in their lyophilized IgG diluted with saline. The results demonstrated high values of 20.2, 25.5 and 21.2 pmol/1 respectively, also showing good parallelism. These immunological parallels to human ß-endorphin verify that a part of the amino acid sequence of human IgG is similar to that of human ß-endorphin.Consequently, in the measurement of ß-endorphin with polyclonal antibody, the results may sometimes be spuriously high due to cross-reaction with IgG, e. g. in patients with IgG myeloma. To avoid IgG interference, a specific monoclonal antibody to synthetic ß-endorphin should be used rather than polyclonal antibodies.

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Section: Discussionmentioning

confidence: 99%

Interference of Immunoglobulins in the Radioimmunoassay of Human β-Endorphin

Hashimoto¹,

Miyabo²,

Nishibu³

et al. 1990

Clinical Chemistry and Laboratory Medicine

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“…Epinephrine was measured by modification of the method of Bouloux et al (1985), using high-pressure liquid chromatography with electrochemical detection. [3-Endorphin was measured by immunoradiometric assay (Voellmy et al 1988) (kits purchased from Nickels Institute, San Juan Capistrano, CA).…”

Section: Methodsmentioning

confidence: 99%