Research from University of Schleswig-Holstein reveals new findings on immunology
2007 NOV 21 -- According to a study from Kiel, Germany, "IgA is the most abundantly produced Ab isotype in humans, but its potential as immunotherapeutic reagent has hardly been explored. In this study, we describe anti-tumor mechanisms of mouse/human chimeric IgA Abs against the epidermal growth factor receptor (EGF-R)." "EGF-R Abs of IgG isotype are currently approved for the treatment of colon or head and neck cancers. As expected, the human IgG1, IgA, and IgA, variants of the 225 Ab demonstrated similar binding to EGF-R. Furthermore, IgA Abs were as effective as IgG in mediating direct effector mechanisms such as blockade of EGF binding, inhibition of EGF-R phosphorylation, and induction of growth inhibition. None of the three variants induced complement-mediated lysis. Human IgG1 effectively recruited MNC for ADCC, but activated PMN only weakly, whereas both IgA isoforms proved to be effective in triggering neutrophils. Interestingly, the IgA(2) isoform was significantly superior to its IgA, counterpart in recruiting PMN as effector cells. Because neutrophils constitute the most abundant effector cell population in human blood, this enhanced neutrophil recruitment lead to increased killing of EGF-R expressing tumor cells in whole blood assays. This killing was further enhanced when blood from G-CSF-primed donors was compared with healthy donor blood," wrote M. Dechant and colleagues, University of Schleswig-Holstein. The researchers concluded: "Together, these data suggest EGF-R Abs of human IgA isotype to bear promise for therapeutic use in cancer." Dechant and colleagues published their study in the Journal of Immunology (Effector mechanisms of recombinant IgA antibodies against epidermal growth factor receptor. Journal of Immunology, 2007;179(5):2936-2943). For more information, contact T. Valerius, University of Schleswig Holstein, Division Nephrology, Campus Kiel, Schittenhelmstr 12, Kiel, Germany. Publisher contact information for the Journal of Immunology is: American Association Immunologists, 9650 Rockville Pike, Bethesda, MD 20814, USA. Keywords: Germany, Kiel, Immunology, University of Schleswig-Holstein. This article was prepared by Immunotherapy Weekly editors from staff and other reports. Copyright 2007, Immunotherapy Weekly via NewsRx.com.
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