Production, binding characteristics and protective immunity of monoclonal antibody to pneumococcal type-9V conjugate.
A monoclonal antibody (MAb) to pneumococcal type-9V polysaccharide (PS) was produced using PS conjugated to inactivated pneumolysin as the immunogen. The MAb to 9V PS was of the IgG1 subclass. The antigen-antibody reaction increased rapidly at low concentrations and reached a plateau at 10 micrograms PS/ml as measured by nephelometry of the group 9 PS against 9V MAb binding. In contrast, the binding of group 9 PS against rabbit 9V antiserum (AS) increased proportionally and continued to increase up to the highest concentration of PS tested (20 micrograms PS/ml). The 9V MAb reacted with all group 9 PSs (9A, 9L, 9N and 9V) by immunodiffusion. In the homologous 9V Ag-MAb reaction, there were marked differences in the inhibition of binding by the cross-reactive 9L PS (19.2% inhibition) and the 9N PS (0.2%). In contrast, inhibition of the homologous 9V Ag-rabbit AS binding by cross-reactive 9L and 9N PSs ranged from 57.8 to 62.7%. Removal of the O-acetyl group from 9V PS by alkali hydrolysis resulted in decreased binding with rabbit 9V AS. However, the binding reaction with 9V MAb was less affected by the loss of O-acetyl content. The 9V MAb was both opsonic and passively protected young mice against challenge with type-9V pneumococci.
Lee
C J
CJ
Center for Biologics Evaluation and Research, FDA, Rockville, MD 20852-1448, USA.
Karpas
A
A
Wang
T R
TR
Kosaka
T
T
Koizumi
K
K
D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D000942:Antigens, Bacterial / Q000737:chemistry / Q000276:immunology*; D002240:Carbohydrate Sequence; D003429:Cross Reactions; D005260:Female; D006825:Hybridomas / Q000276:immunology; D007116:Immunization, Passive; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009895:Opsonin Proteins; D010587:Phagocytosis; D011008:Pneumococcal Infections / Q000276:immunology* / Q000517:prevention & control; D011135:Polysaccharides, Bacterial / Q000737:chemistry / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000276:immunology*
D000907:Antibodies, Bacterial; D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D009895:Opsonin Proteins; D011135:Polysaccharides, Bacterial; C087865:pneumococcal polysaccharide type 9V