Harry E Prince1, Cindy Yeh. 1. Focus Diagnostics, Inc., Cypress, CA 90630, USA. hprince@focusdx.com
Abstract
BACKGROUND: Approximately 6% of sera positive in a dengue virus IgM-capture enzyme immunoassay (EIA) represent false-positives due to interaction between IgM and horseradish peroxidase (HRP)-labeled monoclonal antibody (MAb) 6B6C1 (IgG2a). To better understand this interaction, we assessed the reactivity of captured IgM from these sera with other HRP-labeled MAbs. METHODS: Fifty dengue IgM false-positive sera (recognizing 6B6C1) were evaluated for IgM reactivity with the HRP-labeled MAbs H3A4 (IgG2a), 53.8 (IgG2b), and IL-A2 (IgG1). The sera were also tested in an EIA for human anti-mouse antibody (HAMA). RESULTS: Forty-three sera (86%) reacted with IgG2a MAb (H3A4). Most (31/43 = 72%) of these sera recognizing 6B6C1 and H3A4 also recognized the IgG2 MAb and/or the IgG1 MAb. In contrast, HAMA was increased in only 9 of 50 (18%) sera reacting with 6B6C1. CONCLUSIONS: IgM from most sera-binding IgG2a MAb 6B6C1 also binds another IgG2a MAb, suggesting that IgM-6B6C1 reactivity is not idiotype specific. In many cases, IgM recognizing 6B6C1 also binds MAbs of other IgG subclasses, but is negative in a HAMA assay. These findings indicate that samples positive in IgM-capture EIAs utilizing conjugated MAbs should always be retested in the absence of antigen to identify false-positive reactivity caused by direct IgM-MAb interaction.
BACKGROUND: Approximately 6% of sera positive in a dengue virus IgM-capture enzyme immunoassay (EIA) represent false-positives due to interaction between IgM and horseradish peroxidase (HRP)-labeled monoclonal antibody (MAb) 6B6C1 (IgG2a). To better understand this interaction, we assessed the reactivity of captured IgM from these sera with other HRP-labeled MAbs. METHODS: Fifty dengue IgM false-positive sera (recognizing 6B6C1) were evaluated for IgM reactivity with the HRP-labeled MAbs H3A4 (IgG2a), 53.8 (IgG2b), and IL-A2 (IgG1). The sera were also tested in an EIA for human anti-mouse antibody (HAMA). RESULTS: Forty-three sera (86%) reacted with IgG2a MAb (H3A4). Most (31/43 = 72%) of these sera recognizing 6B6C1 and H3A4 also recognized the IgG2 MAb and/or the IgG1 MAb. In contrast, HAMA was increased in only 9 of 50 (18%) sera reacting with 6B6C1. CONCLUSIONS: IgM from most sera-binding IgG2a MAb 6B6C1 also binds another IgG2a MAb, suggesting that IgM-6B6C1 reactivity is not idiotype specific. In many cases, IgM recognizing 6B6C1 also binds MAbs of other IgG subclasses, but is negative in a HAMA assay. These findings indicate that samples positive in IgM-capture EIAs utilizing conjugated MAbs should always be retested in the absence of antigen to identify false-positive reactivity caused by direct IgM-MAb interaction.
Authors: M Iitaka; S Kitahama; N Fukasawa; S Miura; Y Kawakami; S Sakurai; M Yanagisawa; J Ishii Journal: Intern Med Date: 1992-08 Impact factor: 1.271
Authors: Natalie A Prow; Yin X Setoh; Rebecca M Biron; David P Sester; Kwang Sik Kim; Jody Hobson-Peters; Roy A Hall; Helle Bielefeldt-Ohmann Journal: J Virol Date: 2014-06-18 Impact factor: 5.103
Authors: Alison Jane Basile; Christin Goodman; Kalanthe Horiuchi; Janeen Laven; Amanda J Panella; Olga Kosoy; Robert S Lanciotti; Barbara W Johnson Journal: J Virol Methods Date: 2015-09-03 Impact factor: 2.014