By a News Reporter-Staff News Editor at Biotech Week -- Researchers detail new data in Immunology. According to news originating from King of Prussia, Pennsylvania, by NewsRx correspondents, research stated, "An electrochemiluminescent (ECL) bridging assay to detect anti-ofatumumab antibodies (ADA) in human serum samples was developed and validated. Using this assay format, clinical samples were first screened to identify potential ADA positive samples, which were then further tested by adding excess drug, confirming the positive signals as drug specific."
Our news journalists obtained a quote from the research from GlaxoSmithKline, "However, when the method was implemented into clinical studies for ADA testing, a high positive rate was observed in the pre-dose samples collected from patients with chronic lymphocytic leukemia (CLL). Since the positive signals were not associated with ofatumumab (Ofa) treatment, and diminished after treatment, it was suspected that matrix interference might be responsible, resulting in false-positive responses. We performed a series of experimental investigations to identify, characterize, minimize or eliminate the possible false-positive responses. One possible source was identified to be CD20 (the target of Ofa) present on cell membrane fragments (CMFs). The false-positive responses caused by CD20(+) CMFs could be reduced by solid-phase immunodepletion, ultracentrifugation, or inhibited by adding another anti-CD20 antibody (rituximab)."
According to the news editors, the research concluded: "As a consequence, the ADA method was modified to minimize the matrix interference caused by CD20(+) CMFs and, then, validated for sample testing."
For more information on this research see: False-positive immunogenicity responses are caused by CD20(+) B cell membrane fragments in an anti-ofatumumab antibody bridging assay. Journal of Immunological Methods, 2013;394(1-2):22-31. Journal of Immunological Methods can be contacted at: Elsevier Science Bv, PO Box 211, 1000 Ae Amsterdam, Netherlands. (Elsevier - www.elsevier.com; Journal of Immunological Methods - www.elsevier.com/wps/product/cws_home/506022)
The news correspondents report that additional information may be obtained from K.G. Chen, GlaxoSmithKline, Biopharm R&D, Clin Immunol, King Of Prussia, PA 19406, United States. Additional authors for this research include J.G. Page, A.M. Schwartz, T.N. Lee, S.L. DeWall, D.J. Sikkema and C. Wang (see also Immunology).
Keywords for this news article include: Antibodies, Treatment, Immunology, Pennsylvania, United States, Cell Membrane, Blood Proteins, King of Prussia, Immunoglobulins, Cellular Structures, North and Central America
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