RESUMEN
Hepatitis B virus (HBV) genotyping and hepatitis B surface antigen (HBsAg) subtyping were carried out on sera from 196 HBsAg-positive patients, including 151 refugees entering the United States and 45 injection drug users in Seattle. HBsAg subtyping was performed by enzyme immunoassay (EIA) using a panel of monoclonal antibodies and the HBV genotype was determined by polymerase chain reaction (PCR) followed by detection of amplified HBV DNA by a reverse-phase hybridization line probe assay (LiPA) using genotype-specific probes. HBV DNA was detected by PCR in 155 (79%) of the 196 sera and all 155 were genotyped by LiPA. Samples from Southeast Asia were predominantly genotype B/subtype ayw1 and genotype C/adr; samples from the former Soviet Union and eastern Europe were mostly genotype D/ayw2 and genotype D/ayw3; samples from east Africa were mainly genotype A/adw2 and genotype D/ayw2; and samples from injection drug users were mostly genotype D/ayw3 and genotype A/adw2. Some strains of ayw3 gave atypical monoclonal antibody reactivity patterns in the subtyping assay due to a Val/Ala instead of a Thr at amino acid residue 118 and a Thr instead of a Met at residue 125. A strain of ayw2 also gave an atypical monoclonal antibody reactivity pattern due to an Ala instead of a Thr at amino acid residue 123. LiPA genotyping and monoclonal EIA subtyping can provide useful information for epidemiological studies.
Asunto(s)
Antígenos de Superficie de la Hepatitis B/análisis , Antígenos de Superficie de la Hepatitis B/inmunología , Antígenos e de la Hepatitis B/análisis , Virus de la Hepatitis B/clasificación , Virus de la Hepatitis B/genética , Hepatitis B/virología , Juego de Reactivos para Diagnóstico , Refugiados , Abuso de Sustancias por Vía Intravenosa/virología , África Oriental/epidemiología , África Oriental/etnología , Secuencia de Aminoácidos , Anticuerpos Monoclonales/clasificación , Anticuerpos Monoclonales/inmunología , Asia Sudoriental/epidemiología , Asia Sudoriental/etnología , Secuencia de Bases , Secuencia de Consenso , Europa Oriental/epidemiología , Europa Oriental/etnología , Genotipo , Haití/epidemiología , Haití/etnología , Hepatitis B/epidemiología , Antígenos de Superficie de la Hepatitis B/sangre , Antígenos de Superficie de la Hepatitis B/clasificación , Virus de la Hepatitis B/inmunología , Humanos , Técnicas para Inmunoenzimas , Persona de Mediana Edad , Medio Oriente/epidemiología , Medio Oriente/etnología , Noroeste de Estados Unidos , U.R.S.S./epidemiología , U.R.S.S./etnología , Estados UnidosRESUMEN
The adw4 subtype of hepatitis B virus (HBV) belongs to a unique genomic group (genotype F) representing the original HBV strains from the New World. Data regarding the prevalence of this subtype among HBV carriers in South America are, however, scarce, and those concerning HBV genotype F are based on only a few samples from Latin America. In this study, serum samples were obtained from 141 hepatitis B surface antigen (HBsAg) carriers from Amerindians and urban populations from Venezuela. The HBsAg subtype was identified with monoclonal antibodies in 105 samples, and the HBV genotype was identified by reverse-phase hybridization with DNA fragments in 58 samples. The adw4 subtype was highly prevalent in the population studied (75%); among the Amerindians, the prevalence was 97%. The adw2 subtype was also present (10%), while other subtypes (ayw3 and ayw4) were only occasionally found. The HBV subtype was associated with the expected genotype in most cases (80%), and thus genotype F was highly prevalent. Sequencing of viral strains that gave genotypes unpredicted by the HBsAg subtyping confirmed seven of them as belonging to not previously described genotype-subtype associations: namely, adw2 and ayw4 within genotype F.