Impact of hepatitis B virus genotype F on in vitro diagnosis: detection efficiency of HBsAg from Amerindian subgenotypes F1b and F4.
Limeres, M. J., Gomez, E. R., Noseda, D. G., Cerrudo, C. S., Ghiringhelli, P. D., Nusblat, A. D. and Cuestas, M. L.
CONICET, Instituto de Investigaciones en Microbiologia y Parasitologia Medica (IMPaM), Universidad de Buenos Aires, Buenos Aires, Argentina.
Instituto de Agrobiotecnologia y Biologia Molecular, INTA-CONICET, Buenos Aires, Argentina.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico de Chascomus (IIB-INTECH), Universidad Nacional de San Martin (UNSAM)-Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires, Argentina.
Departamento de Ciencia y Tecnologia, Laboratorio de Ingenieria Genetica y Biologia Celular y Molecular, Area Virosis de Insectos (LIGBCM-AVI), Instituto de Microbiologia Basica y Aplicada (IMBA), Universidad Nacional de Quilmes, Bernal, Provincia de Buenos Aires, Argentina.
Facultad de Farmacia y Bioquimica, Instituto de Nanobiotecnologia (NANOBIOTEC), Universidad de Buenos Aires, Buenos Aires, Argentina.
CONICET, Instituto de Investigaciones en Microbiologia y Parasitologia Medica (IMPaM), Universidad de Buenos Aires, Buenos Aires, Argentina. marilucuestas@gmail.com.
The influence of the high genetic variability of hepatitis B virus (HBV) on the sensitivity of serological assays has received little attention so far. A major source of variability is related to viral genotypes and subgenotypes. Their possible influence on diagnosis and prophylaxis is poorly known and has mostly been evaluated for genotypes A, B, C and D. Robust data showing the detection efficiency of HBsAg from genotype F is lacking. This study examined the effect of virus-like particles containing HBsAg from genotypes A and F (particularly, F1b and F4) produced in Pichia pastoris in relation to the anti-HBs antibodies used in the immunoassays for in vitro diagnosis and compared it with that exerted by the G145R S-escape mutant. The results showed that HBsAg detection rates for subgenotypes F1b and F4 differed significantly from those obtained for genotype A and that subgenotype F1b had a major impact on the sensitivity of the immunoassays tested. Prediction of the tertiary structure of subgenotypes F1b and F4 revealed changes inside and outside the major hydrophilic region (aa 101-160) of the HBsAg compared to genotype A and the G145R variant. A phosphorylation site (target for protein kinase C) produced by the G145R substitution might prevent recognition by anti-HBs antibodies. In conclusion, the use of different genotypes or variants for diagnosis could improve the rate of detection of HBV infection. The incorporation of a genotype-F-derived HBsAg vaccine in areas where this genotype is endemic should be evaluated, since this might also affect vaccination efficacy.
Archives of Virology 164(9): 2297-2307 (2019)