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Objective To investigate the distribution and sequence conservation of Hap adhensin encoding gene (hap) in clinical isolates of nontypeable Haemophilus influenzae (NTHi), to screen out and identify the predominant T-and B-cell (T-B) combined antigenic epitopes on Hap protein and to analyze their immunogenicity.Methods Sequence conservation of hap genes in NTHi strains and T-B combined antigenic epitopes were predicted using bioinformatic softwares.PCR was used to amplify the 156 bp segment at 5′-end and the 855 bp segment at 3′-end of hap gene (hap-5′-156 and hap-3′-855) and the amplified products were sequenced.Phage display systems of seven T-B combined antigenic epitopes located on the 55 aa segment at N-terminal and the 285 aa segment at C-terminal of Hap protein (Hap-N52 and Hap-C285) were constructed.Western blot assay and ELISA were performed to detect the antigenicity and immunoreactivity of different T-B combined epitopes displayed by recombinant phage PⅢ protein (rPⅢ).Results Hap protein encoded by the hap gene in NTHi was located on membrane surface.Sequences of the 156 bp segment at 5′-end and the 855 bp segment at 3′-end of hap genes extracted from different NTHi strains were relatively conservative, but many mutations were found in sequences at the middle regions of these hap genes.All of the 56 NTHi strains carried hap-5′-156 and hap-3′-855 segments and shared 92.3％-100％ identities in nucleotide and amino acid sequences of these segements.Hap-N5-24 in the Hap-N52 segment as well as Hap-C4-27, Hap-C28-47, Hap-C114-129, Hap-C150-173, Hap-C200-227 and Hap-C241-267 in the Hap-C285 segment was predicted as the T-B combined antigenic epitope with a higher score and less mutations.Results of Western blot assay and ELISA confirmed that the rPⅢ-displayed Hap-C4-27 and Hap-C150-173 epitopes presented clear hybridization bands with NTHi antisera, and 96.9％ (63/65) and 92.3％ (60/65) of serum samples from children with NTHi infection were positive for antibodies against Hap-C4-27 and Hap-C150-173 epitopes, respectively.Conclusion The gene of hap is widely distributed in clinical isolates of NTHi.Moreover, sequences of the 156 pb segment at 5′-end and the 855 bp segment at 3′-end of hap gene are conservative.Hap-C4-27 and Hap-C150-173 are the predominant T-B combined antigenic epitopes on Hap protein, suggesting that they can be used as epitope candidates for developing multiple antigenic peptide vaccines against NTHi.
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Objective To explore the effects of maternal allergy symptoms on the cytokine level of umbilical cord blood of neonates.Methods A cross sectional study was conducted among 136 pregnant women in Yiwu city from 1st July to 30th December,in 2012.A questionnaire on social economic charactertistics was used and blood sam-ple of pregnant women and umbilical cord blood sample were collected to detect the level of IgE,eosinophile granulo-cyte,Eotaxin,IL-9,IL-6,IL-4,IL-5,IFN-γ,IL-10.The differences between pregnant women with and without allergy symptoms were carried out.Results There were no significant differences in social and demographic characteristics between the two groups(all P>0.05).Pregnant women with allergy symptoms had higher IgE level(0.13 IU/mL vs 0.10 IU/Ml,Z=-2.063,P=0.039),eosinophile granulocyte(0.39 ×109/mL vs 0.29 ×109/mL,Z=-2.548, P=0.011),Eotaxin(66.18ng/L vs 48.35ng/L,Z=-2.144,P=0.032),IFN-γ(927.81ng/L vs 338.65ng/L,Z=-2.051,P=0.040),IL-10(15.59ng/L vs 11.55ng/L,Z=-2.022,P=0.043) than pregnant women without allergy symptoms in neonates′cord blood.Conclusion Maternal allergy symptoms may increase the level of IgE, eosinophile granulocyte,Eotaxin,IFN-γand IL-10 of neonates′cord blood.
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Objective To investigate the distribution and sequence conservation of genes encoding the outer membrane lipoprotein D(LPD)of nontypeable Haemophilus influenzae(NTHi)isolates and to ana-lyze the immunogenicity and the immunoprotective effects of the expressed recombinant LPD(rLPD). Meth-ods PCR analysis was used to detect the genes encoding LPD of NTHi isolates. The PCR products were se-quenced after T-A cloning. A prokaryotic expression system for genes encoding LPD was established to ex-press the rLPD. Ni-NTA affinity chromatography was used for purification. SDS-PAGE and Bio-Rad Gel Im-age Analyzer were used to detect the expression and the yield of rLPD. The antigenicity and immunoreactivity of rLPD were detected by ELISA and Western blot assay. The immunoprotective effects of rLPD against lethal dose of NTHi were evaluated in a mouse model. Results All of the tested NTHi isolates were positive for the genes encoding LPD. They shared 98. 0% -99. 4% homologies in nucleotide sequences and 98. 5% -100% homologies in amino acid sequences. The established prokaryotic expression system expressed rLPD with a high yield. High levels of antibody in rabbits were induced by the rLPD. The anti-NTHi antiserum samples from rabbits and children could recognize and react with the rLPD. The result of ELISA indicated that 93. 6%(58 / 62)and 53. 2%(32 / 62)of the serum samples from children with NTHi infection were positive for rLPD-IgM and rLPD-IgG,respectively. The rLPD at concentrations of 100 μg and 200 μg could respectively protect 60. 0% and 73. 3% of mice from lethal NTHi infection. Conclusion The genes enco-ding LPD were extensively distributed in NTHi isolates with high sequence conservation. The expressed rLPD could be used as a potential candidate antigen in the development of genetic engineering vaccine against NTHi infection considering its high immunogenicity and immunoprotective effects.
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Objective To explore a rapid diagnostic method in neonatal sepsis and bacterial me- ningitis. Methods The primers and TaqMan probes were designed and synthesized based on the sequences of bacterial 16S rRNA gene. Nineteen bacterial strains, 3 different viruses, fungus and human genomic DNA were tested by FQ-PCR assay. Blood specimens and CSF from 195 cases of suspected septicemia were detected with both TaqMan PCR assay and blood or/and CSF culture. Results The FQ-PCR showed very high sensitivity and specificity and was able to detect at least 10 copies of 16S rRNA gene equivalent to 1~2 copies bacterium. No cross-reaction was found with human genomic DNA, other fungus and viruses. Among the 195 cases, the positive rate by FQ-PCR was 12.8%(25 cases) and 7.1%(15 cases) by blood culture ( P