@article {AVRAMIS299, author = {VASSILIOS I. AVRAMIS and EARL V. AVRAMIS and WILLIAM HUNTER and MELISSA C. LONG}, title = {Immunogenicity of Native or Pegylated E. coli and Erwinia Asparaginases Assessed by ELISA and Surface Plasmon Resonance (SPR-Biacore) Assays of IgG Antibodies (Ab) in Sera from Patients with Acute Lymphoblastic Leukemia (ALL)}, volume = {29}, number = {1}, pages = {299--302}, year = {2009}, publisher = {International Institute of Anticancer Research}, abstract = {Background: Therapeutic uses of asparaginases (ASNase) have been shown to elicit immune responses resulting in the development of potentially life-threatening human anti-bacterial antibodies (Ab). A robust screening enzyme-linked immunosorbent assay (ELISA) to detect binding Ab(+) against ASNase has been developed and validated for therapeutic monitoring to support clinical trials. Recently, a protein chip bioassay (Biacore) was developed for the Ab of these proteins. These methods were compared. Materials and Methods: A Biacore T-100 analyzer using a protein bioassay and an ELISA assay were used to determine the IgG immmuboglobulin Ab against ASNase in sera from 84 acute lymphoblastic leukemia (ALL) patients plus 6 controls (n=121 samples). These samples were characterized for anti-ASNase Ab neutralizing activity. Human E. coli ASNase, pegaspargase and Erwinase proteins were covalently coupled to the carboxy-methylated dextran matrix of a CM5 sensor chip (surface plasmon resonance, SPR). In the course of a nested experimental design, a wide range of human sera from patients who had obvious clinical allergic reactions after either native or pegaspargase treatments were tested. The data were fitted by a parametric logistic equation ({\textpm}95\% confidence interval, CI), which ranged from \<3.0\% to \<14\% . Results: The specificity of Ab(+) was evaluated using {\textquotedblleft}spiked{\textquotedblright} human IgG antibodies. Both assays provide near excellent linearity and sensitivity of response (\<0.8 to \<500 ratio and 1-3000 resonance units [RU]) of anti-ASNase Ab in human sera with low variance. The bioassay method was ten times more sensitive than the ELISA Ab assay. The lowest limit of quantification of Ab(+) ratio for the SPR assay was 0.6 whereas the upper limit of quantification was 3,000 RU. The SPR assay results were in excellent accord with both the Ab(-) and the Ab(+). Ab(-) by the ELISA method (\<1.003 ratio) was related to a mean RU value of 8.1. Despite the narrow range of ambiguity around the 1.1 Ab(+) ratio values, the majority of the specimens (93.2\%) were determined to be Ab(+) by either ELISA or SPR determination. Conclusion: The vast majority (81/84 = 96.4\%) of the IgG Ab(+) were neutralizing. The SPR Ab determination technique is reliable, accurate and more sensitive than the ELISA method. Copyright{\textcopyright} 2009 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved}, issn = {0250-7005}, URL = {https://ar.iiarjournals.org/content/29/1/299}, eprint = {https://ar.iiarjournals.org/content/29/1/299.full.pdf}, journal = {Anticancer Research} }