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[Objects]To isolate and identify the pathogen of the large outbreak of dengue in Guangdong province in 2014. To understand the origin and the phylogenetic characteristics of the isolates ,and provide scientific foundation for the surveillance and prevention of dengue fever.[Methods]Collected the patient serum samples over all the Guangdong province during the 2014 outbreakperiod,isolated and identified the virus from these samples. Amplified complete E gene and complete genome with certain primers and sequenced all the products. Then the Phylogenetic ,Bayesian phylogeography and mutations analysis were carried.[Results]40 DENV-1 strains were isolated and identified. 40 complete E gene sequences and 6 complete genome sequences of DENV-1 were obtained. Phylogenetic analysis with E gene sequences revealed that the 40 isolates were classified into two genotypes including 16 genotypeⅠ(Asia)and 24 genotypeⅤ(America/Africa). 14 genotypeⅠisolates were clustered closest with isolates from Guangdong province(2013)and Sigapore(2013)which share the nucletide identities of 99.6% ~ 99.9%,other two genotypeⅠisolates were clustered with strains from Malaysia (2013) and both share the nucletide identities of 99.7%;24 genotypeⅤisolates were all classified in one clade with striains from Bangladesh(2009),China(2009)and Bhutan(2013)which share nucletide identities of 99.0%-99.9%. Further analysis with six complete genome sequences showed that five isolates were clustered closest with strains isolated from Guangdong province(2013)share the nucletide identities of 99.6%-99.8% while the sixth stains closest with strains isolated from Myanmar(2002)share the nucletide identities of 98.8%. The isolates have five amino acid mutations compared with strains epidemic in Guangdong province in 2013,three mutations(S88V,E203G,T275R)are in the EⅡdomain and one mutation (S305P)is in the EⅢdomain which associated with virulence.[Conclusions]During the outbreak in Guangdong province in 2014, DENV-1 is the predominant causative serotype,and there are at least two different kinds of genotypes of DENV-1 largely epidemiced in the whole province. Evolution analysis reveals the multiple origins of the isolates which may origin from Guangdong province , Sigapore,Malaysia,Myanmar so that we should enhance the study and surveillance of autochthonous and vectors in order to understand the epidemic way of dengue in Guangdong province. The isolates have had four mutations in the domain associated with virulence which remain further study to know their biological effects.
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[Objective]This study was designed to investigate the genetic evolution of the neuraminidase(NA)gene of seasonal A/H1N1 and 2009 novel A/H1N1 inflilenza virus,and discuss the genetic variation of influenza A virus.[Methods]The virus strains were separately isolated from the clinical samples collected in 2006 and 2009,and then identified as seasonal A/H1N1 and novel A/H1N1.The full length of the NA gene of these strains was amplified by RT-PCR.Then the genetic evolution and mutations of important functional sites were analyzed.[Results]The homology of NA gene between the 2009 novel A/H1N1 isolates and 2006 seasonal A/H1N1 isolates was low(77.9%～78.8%),so was the homology of NA gene between the 2009 novel A/H1N1 isolates and representative strains of different periods and 1979-2001 WHO recommended vaccine strains(78.1%～79.3%).But compared with the WHO recommended vaccine strains of 2009 novel A/H1N1,the homology reached more than 99%.The genetic evolution analysis revealed that NA gene of 2009 novel A/H1N1 had the closest genetic relationship with the swine influenza A virus(A/swine/Belgium/1/1983)from Eurasian Iineage,and some of the antigenic sites and neuraminidase active sites of NA gene of seasonal A/H1N1 were mutated after 2005.[Conclusion]The NA gene of 2009 novel A/H1N1 may originate from Eurasian Iineage of swine influenza virus.The variation of NA gene of seasonal A/H1N1 has occurred in a certain degree.Hence,it is very necessary to continuously monitor the variant of influenza A virus.
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Objective To detect dengue virus infection by serological method and to determine the sequences of E gene of dengue virus isolated from Guangzhou in 2006.so as to clarify the possible origin of dengue fever.Methods IgM and IgG antibodies to dengue virus were detected by immunochromatographic test(ICT);NSI antigen and IgM antibody were detected by enzyme-linked immunosorbent assay(ELISA).The virus was cultured and isolated from the serum samples within 2 days using C6/36 cell lines and was identified by immuno-fluorescence assay(IFA)and RT-PCR.The E gene of isolated virus DV1-GZ42/06 was sequenced;homological analysis and phylogenetic tree analysis were performed by comparing with the reference strains and epidemic virus strains.Results The positive rates of IgM and IgG of dengue virus in patients were 89.5%(433/484)and 38.0%(184/484)by ICT,respectively.The positive rates of NS1 antigen were 92.7%(38/41)in day 1 to day 2,83.3%(70/84)in day 3 to day 5,and 10.9%(5/46)in day 6 to day 10;and the IgM detection rates were 2.4%(1/41),51.2%(43/84)and 97.8%(45/46)at the same period by ELISA.Twenty-five strains of dengue virus were isolated from 41 serum samples(6 1.O%)and were identified as type 1 dengue virus by IFA and RT-PCR.The sequencing and phylogenetic analysis of the E gene showed that the homology between the isolated Guangzhou/42/06 strain and standard strain Hawaii/45 was 94.6%.and it had a high homology with the Thailand/NI09V104,Vietnam/06.and Vietnam/07 isolates(99.0%,98.6%and 98.6%,respectively)and belonged to the same cladogram,but had low homology with the isolated strain from Guangdong before 2006.Conclusions The detection of NS1 antigen is important in the early diagnosis of dengue fever.The outbreak of dengue fever in Guangzhou in 2006 was possibly caused by the cases from neighboring countries.
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AimTo study the effect of interferon gamma( IFN-γ) and tumor necrosis factor alpha(TNF-α) in the immune pathogenesis of dengue virus infection. Method The serum levels of IFN-γ and TNF-α were measured with emzyme linked immunosorbent assay (ELISA) method in 30 cases of the patients with the dengue virus infection in Guangzhou district. The results were treated with t-test of two sample mean. ResultsThe serum levels of IFN-γ and TNF-α in patients with the dengue virus infection were much higher than healthy controls( P ＜ 0.05、 P ＜ 0.01 ). IFN-γ was detectable on the first day of postinfection. Level of IFN-γ reached their peaks on the second day, then declined . The level of TNF-α had an obvious rise from the second day and reached their peaks on the third day, then declined. ConclusionThe data suggest that the IFN-γ and TNF-α may play an important role in the dengue virus pathogenicity and immunity.
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Objective:To establish a method of multi-PCR to amplify the complete DNA sequence (CDS) of TCR ? and ? chain of the antigen-specific T lymphocytes in local pathologic specimen of active pulmonary tuberculosis patients, and to analyze ?/? T cell receptor gene rearrangement and CDR3 repertoire.Methods:The lymphocytes in bronchoalveolar lavage (BAL) of active pulmonary tuberculosis patients were separated. Following total RNA extraction, cDNA synthesis, Multi-PCR, recombinant clones construction, and sequencing, the CDS of TCR ? and ? chains from these lymphocytes were analyzed by using software of DNAstar and internet TCR resources.Results:24 of ? chain CDS and 13 of ? chain CDS from 3 samples of BAL were obtained. As for TCR ? chain, AV1S2 (54%), AV12S3 (41%), and AV12S2(5%) appeared frequently. BV2(38%), BV29S1(46%), BV14(3%), and BV4S2(3%) in TCR ? chain appeared more often. There were CDR3 diversities between samples and even in the same sample by amino acid sequence analysis, but there were a few identical or similar amino acid sequences. There was the same amino acid sequence of SVGTGTLHQETQY in CDR3 region of ? chain of BAL sample No.1 and No.2; The sequence of AVRDWAGNMLT appeared in two ? chains of BAL sample No.2 and No.3; Moreover, the sequence of AV…DNN…RLM appeared in ? chains of BAL sample No.2 and No.3.Conclusion:A method of Multi-PCR is used to amplify TCR ? and ? chain CDS of tuberculosis patients. There are characteristic T cell clones to proliferate,with TCR ? and ? chain repertiore skewing in local infective focus. The sequences of CDR3 in different TCR clones are mostly different but there are a few identical or similar sequences in the same patient or even between different patients. The identical amino acid sequences of CDR3 are possibly specific for recognizing MTB polypeptide.