A novel assay to measure B cell responses to keyhole limpet haemocyanin vaccination in healthy volunteers and subjects with systemic lupus erythematosus |
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Authors: | John Ferbas Shelley S Belouski Michelle Horner Arunan Kaliyaperumal Li Chen Malcolm Boyce C Bernie Cola?o Neil McHugh Vanessa Quick Richard J Nicholl Gerald Siu James Chung |
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Affiliation: | 1.Department of Medical Sciences, Amgen, Inc, Thousand Oaks, CA, USA;2.Department of Comparative Biology and Safety Sciences, Amgen, Inc, Thousand Oaks, CA, USA;3.Department of Inflammation, Amgen, Inc, Thousand Oaks, CA, USA;4.Hammersmith Medicines Research, London, UK;5.Royal National Hospital for Rheumatic Diseases, Bath, UK |
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Abstract: | The aim of the study was to characterize performance of a complementary set of assays to measure antigen-specific immune responses in subjects immunized with a neoantigen. Healthy volunteers (HV) (n = 8) and patients with systemic lupus erythematosus (SLE) (n = 6) were immunized with keyhole limpet haemocyanin (KLH) on days 1 and 29. Serum antibodies were detected using a flow cytometric bead array (CBA) that multiplexed the KLH response alongside pre-existing anti-tetanus antibodies. Peripheral blood mononuclear cells were studied by B cell ELISPOT. These assays were built upon precedent assay development in cynomolgus monkeys, which pointed towards their utility in humans. Primary anti-KLH IgG responses rose to a mean of 65–93-fold above baseline for HV and SLE patients, respectively, and secondary responses rose to a mean of 260-170-fold above baseline. High levels of anti-tetanus IgG were detected in pre-immunization samples and their levels did not change over the course of study. Anti-KLH IgG1-4 subclasses were characterized by a predominant IgG1 response, with no significant differences in subclass magnitude or distribution between HV and SLE subjects. Anti-KLH IgM levels were detectable, although the overall response was lower. IgM was not detected in two SLE subjects whodid generate an IgG response. All subjects responded to KLH by B cell ELISPOT, with no significant differences observed between HV and SLE subjects. The CBA and B cell ELISPOT assays reliably measured anti-KLH B cell responses, supporting use of this approach and these assays to assess the pharmacodynamic and potential safety impact of marketed/investigational immune-therapeutics. |
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Keywords: | ELISPOT immunoassay flow cytometric bead immunoassay keyhole limpet haemocyanin systemic lupus erythematosus vaccine response |
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