Samenvatting

Since Factor H is the main regulator of the complement system, any dysregulation may result in either uncontrolled complement activation or inhibition. Auto-antibodies against Factor H inhibit the protective function of Factor H on host cells, which are now sensitive for complement activation. It is known that kidney cells are extremely sensitive for complement activation when the function of Factor H is lacking, caused by either genetic Factor H deficiencies or auto-antibodies. These auto-antibodies are associated with several complement-related diseases like aHUS, MPGN, or C3GN. In most cases patients will develop end-stage renal disease by early adolescence. Therefore, an anti-Factor H ELISA is developed to measure auto-antibodies against Factor H in serum. A first attempt was based on anti-Factor H ELISA´s described in literature, where Factor H was directly coated on an ELISA plate. Since this was not working at our lab, due to measuring a lot of aspecific signals in healthy donors, Factor H was catched indirectly by coating an anti- Factor H monoclonal antibody. Due to the fact that these aFH-antibodies are relatively “rare” in patients, a representative and stable standard was lacking. For that reason, we tried to chimerize a mouse anti-Factor H monoclonal antibody. We ligated aFH light- and heavy –chains constructs in a pcDNA3.1 plasmid. After transformation into Top 10F’ E. coli, multiple transfections were performed into HeK293T cells. However, we were not able to detect any chimeric mAb in the HeK293T supernatant. To continue, a new transfection will be performed with sequences of either light- and heavy –chains which have different signal peptides than previously ordered. When the chimerisation is completed successful, aFH chimeric antibodies can be used as a stable standard in the aFH ELISA. Furthermore, patients whom are clinically suspected for anti-Factor H presence will be tested in this aFH ELISA, as well as a C3NeF positive patient cohort.