QUANTITATION OF IGG SUBCLASS ANTIBODY-RESPONSES AFTER IMMUNIZATION WITH A GROUP-B MENINGOCOCCAL OUTER-MEMBRANE VESICLE VACCINE, USING MONOCLONAL MOUSE-HUMAN CHIMERIC ANTIBODIES AS STANDARDS

An ELISA method was developed to quantitate gravimetrically (mu g/ml) the IgG subclass response against a Norwegian vaccine composed of oute r membrane vesicles (OMV) isolated from a Neisseria meningitidis B:15: P1.7,16 epidemic strain, Chimeric mouse-human anti-hapten NIP (5-iodo- 4-hydroxy-3-nitrophenacetyl) antibodies of each subclass were used for calibration purposes. Before vaccination, low amounts of IgG1 and IgG 2 antibodies against OMV were detectable in all vaccinees, whereas IgG 3 was only detectable in one of the 21 vaccinees. After vaccination, I gG1 antibodies dominated the response followed by IgG3 and low to mode rate levels of IgG2 antibodies. IgG4 was only detectable at very low l evels in a few vaccinees, All sera showed close to parallel dose-respo nse curves to each other for IgG1 and IgG3, whereas the IgG2 curves we re not parallel to chimeric IgG2 and could thus not be quantitated gra vimetrically. For IgG3, 1/3 of the vaccinee sera showed non-parallel d ose-response curves to the rest of the vaccinee sera and to chimeric I gG3 and could not be gravimetrically quantitated, The rest of the sera showed parallel dose-response curves with the chimeric IgG3 and gravi metric quantitation was possible, This study illustrates that chimeric antibodies can be used as calibrators to quantitate Ige subclass anti body responses against OMV in gravimetric units and that the vaccine m ainly induces IgG1 and IgG3 antibodies in humans.