MOUSE HUMAN CHIMERIC IGG1 AND IGG4 ANTIBODIES DIRECTED TO THE HOUSE-DUST MITE ALLERGEN DER-P-2 - USE IN QUANTIFICATION OF ALLERGEN-SPECIFICIGG/

Background and Objective Chimeric mouse/human monoclonal IgG1 and IgG4 antibodies were developed against the house dust mite allergen Der p 2. These chimeric IgG antibodies, hIgG1-Dp2 A and hIgG4-Dp2 A, have th e same binding characteristics as the previously reported chimeric hIg E-Dp2 A and are composed of the heavy chain variable domains and light chains of the original murine monoclonal antibody 2B12, whereas the h eavy chain constant domains have been replaced by the human IgG1 or Ig G4 heavy chain. The expression level of hIgG1-Dp2 A and hIgG4-Dp2 A wa s 1 and 3.5 mu g/mL, respectively. Methods and Results Since all IgG i n these culture supernatants is allergen-specific, they are useful ref erence reagents and enable the calculation of the amount of allergen s pecific IgG 1 and IgG4 antibodies in absolute IgG amounts. The results obtained with two panels of sera from patients in immunotherapeutic t reatment were evaluated and compared in Der p 2 IEE, IgG1 and IgG4 RAS T and with reversed IgG4 PAST using labelled purified Der p 2. Close a greement between the results for the two IgG4 assays was found. Conclu sion With these chimeric reference reagents the quantities of isotype specific antiallergen antibodies can be calculated and compared.