A Western blot assay was standardized to evaluate the antigenic reactivity of hepatitis B virus (HBV) strains circulating in Brazilian population with antibodies raised against recombinant hepatitis B (HB) vaccines. In this assay, HBV envelope proteins from infected human blood were detected by antibodies from rabbits immunized with either of two recombinant vaccines. These were Engerix B (Smith Kline Beecham, Belgium) containing exclusively S protein particles and TGP-943 (Takeda Chemical Industries, Japan) containing M protein particles. Forty-seven serum samples, presenting HB surface antigen. (HBsAg) reverse passive haemagglutination assay (RPHA) titers ranging from 1:32 to > or =1:4096 after HBV particles concentration, were tested. Twenty-seven samples were from acute hepatitis cases and 20 were from chronic cases (11 from cirrhotic patients and 9 from asymptomatic carriers). Four HBV serotypes, adw2, adw4, ayw2 and ayw3, were identified in these samples. Infectivity of these sera was evaluated by HBV DNA detection by polymerase chain reaction PCR). HBV DNA was present in 62% of samples from acute cases and in all samples from chronic cases. Despite the differences between serotypes, genotypes, forms of infection, and infectivity of the samples, antibodies against both vaccines reacted with HBV envelope proteins from all but one sample. In one sample from cirrhotic patient, only a small protein of unexpected size reacted with TGP-943 antibodies.

*Blotting, Western/METHODS *Carrier State/IMMUNOLOGY *Hepatitis B Antibodies/IMMUNOLOGY *Hepatitis B Surface Antigens/IMMUNOLOGY *Hepatitis B Vaccines/IMMUNOLOGY *Hepatitis B Virus/IMMUNOLOGY *Vaccines, Synthetic/IMMUNOLOGY

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