RESUMO
OBJECTIVE: Hantaan virus (HTNV) is one of the main etiologic agents for hemorrhagic fever with renal syndrome in China. However, it is very difficult to isolate the virus from its original host, which hampers the viral characterization. This study describes an efficient method for isolating HTNV in suckling mice. METHODS: Hantavirus-infected Apodemus agrarius were screened by quantitative real-time PCR. The homogenates of one positive rodent lung tissue were inoculated into suckling mice for virus propagation through serial passages. RESULTS: During the three passages in suckling mice, the number of viral RNA copies/nanogram of GAPDH mRNA increased significantly ranging from 477 to 7,278 and 46 to 4,898 in the tissues of brain and lung, respectively. Hantaviral antigens could be detected by indirect immunofluorescence assay and around 100-nm virion-like structures were also observed in brain tissue by transmission electron microscopy. No nucleotide exchange was found except for one in the 3'-non-coding domain of S segment when comparing the complete genome sequences from hantavirus in the first and the third passages. CONCLUSION: These results suggest inoculation of suckling mice with suspected hantavirus-infected rodent samples is an efficient method for isolation and maintenance of HTNV.
Assuntos
Vírus Hantaan/isolamento & purificação , Virologia/métodos , Animais , Animais Recém-Nascidos , Vírus Hantaan/genética , Vírus Hantaan/ultraestrutura , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Eletrônica de Transmissão , Murinae/virologia , RNA Viral/genética , Reação em Cadeia da Polimerase em Tempo Real , Inoculações Seriadas/métodos , Vírion/ultraestruturaRESUMO
BACKGROUND: Interferon might induce mutation in regions of hepatitis B virus DNA that encode for immunologic target of cytotoxic T lymphocytes. AIM: To investigate the short-term effect of steroid priming and interferon therapy on hepatitis B virus, we followed the nucleotide changes in the precore and core region of hepatitis B virus DNA in seven healthy asymptomatic carriers who underwent steroid priming followed by recombinant alpha interferon for 3 months. METHODS: Hepatitis B virus DNA from serial sera of the patients were polymerase chain reaction-amplified, and the precore and core region directly sequenced and analysed. RESULTS: Analysis revealed no serial changes in the hepatitis B virus nucleotide sequence in any of the patients. CONCLUSIONS: Steroid priming and short-term treatment with interferon in healthy asymptomatic patients does not select for hepatitis B virus with mutations in the precore and core region.