RESEARCHER OF THE MONTH August 2017 – Johannes Hofer
Dr. Johannes Hofer was selected MedUni Vienna Researcher of the Month, August 2017, for the work „Ig-like transcript 4 as a cellular receptor for soluble complement fragment C4d“, published in „FASEB Journal“ (IF 5.5).
Complement regulation leads to the generation of complement split products such as complement component (C)4d, a marker for disease activity in autoimmune syndromes or antibody-mediated allograft rejection. However, the physiologic role of C4d has been unknown. The present study identifies Ig-like transcript (ILT)4 and ILT5v2 as cellular receptors for C4d.
Both receptors, expressed on monocytes, macrophages and dendritic cells, also interacted with complement split products C3d, C4b, C3b and iC3b. However, C4d did not bind to classic complement receptors. In monocytes, C4d exerted a dose-dependent inhibition of pro-inflammatory cytokine secretion as well as an attenuation of intracellular Ca2+ flux. Cell surface-resident ILT4 conferred endocytosis of soluble monomeric C4d.
- The research work was carried out during the doctoral studies of Johannes Hofer at the Institute of Immunology in the research group of Univ.-Prof. Dr. G.-J. Zlabinger (Head of the Institute of Immunology) in close collaboration with the research group of Assoc. Prof. Dr. P. Steinberger (Institute of Immunology), as well as in collaboration with the research group of Univ.-Prof. Dr. H. Stockinger (Head of the Institute for Hygiene and Applied Immunology and the Center for Pathophysiology, Infectiology and Immunology), Prof. D.E. Isenman (Dept. of Biochemistry and Immunology, University of Toronto, Canada) and A.o. Univ.-Prof. Dr. G.A. Böhmig (Dept. of Nephrology and Dialysis, KIM III).
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