Quantitation of Group-specificaAntigen in Hepatitis B Vaccines by Anti-HBs/aMonoclonal Antibody

Abstract Balb/c mice were immunized with aluminium hydroxide [alum, Al(OH) 3 ]-adjuvanted hepatitis B (HB) vaccines of subtypes adr , ayw or adw . Spleen cells from the immune animals were fused with SP2/O cells. Eight hybridoma clones producing antibodies specific or HB surface antigen (HBsAg) were selected. Monoclonal antibodies (mAbs) of four clones were specific for group-specific antigen/ a , and the other of four clones were specific for subtype antigen/ d , y , r , or w . The anti-HBs/ a mAbs were classified into three non-competitive groups. Quantitation of group-specific determinant a of HBsAg (HBsAg/ a ) was performed by sandwich enzyme-linked immunosorbent assay (ELISA), in which a solid phase of anti-HBs guinea-pig polyclonal antibodies (pAb), the HBsAg for testing, anti-HBs/ a mouse mAb and horseradish peroxidase (HRP)-conjugated anti-mouse IgG were used. The unadsorbed HBsAg was used to establish the standard curve HBsAg/ a . The lower detection limits were 0·5 to 1 ng/ml of HBsAg. Methods of solubilization of alum were investigated to quantify HBsAg/ a in adsorbed HB vaccines. The recovery rate was more than 60% if vaccines were prediluted. The recovery of HBsAg/ a in HB vaccines produced by the same manufacturer showed the similar recovery rate, and the contents of HBsAg/ a in adsorbed HB vaccines could be estimated by the recovery rate determined for adsorbed HB vaccines.