Anti-OX40 Antibody Combined with HBc VLPs Delays Tumor Growth in a Mouse Colon Cancer Model.

Objective: Combination immunotherapy strategies targeting OX40, a co-stimulatory molecule that can enhance antitumor immunity by modulating the proliferation, differentiation, and effector function of tumor-infiltrating T cells, have attracted much attention for their excellent therapeutic effects. In this study, we aimed to evaluate the antitumor efficacy of combined anti-OX40 and hepatitis B core virus-like particles (HBc VLPs) therapy using a mouse colon cancer model. Methods: Humanized B-hOX40 mice were injected subcutaneously with MC38 colon tumor cells and treated with HBc VLPs+anti-hOX40 antibody. Tumor growth was monitored. Flow cytometric analysis was performed to evaluate the populations of T cell subsets in the tumors. Results: The combination of anti-OX40 with HBc VLPs resulted in a significant delay in tumor growth, suggesting that a potent antitumor immunity was induced by the combination therapy. Further studies revealed that HBc VLPs+anti-OX40 treatment induced a significant increase in effector T cells (Teffs) and a significant decrease in regulatory T cells (Tregs) in the tumor microenvironment (TME), which accounted for the synergistic antitumor effect of anti-OX40 in combination with HBc VLPs. Conclusion: Combination therapy of anti-hOX40 and HBc VLPs provides synergistic antitumor activity in colon cancer-bearing mice, which may represent a potential design strategy for cancer immunotherapy.

A novel mRNA rabies vaccine as a promising candidate for rabies post-exposure prophylaxis protects animals from different rabies viruses.

Rabies, caused by the rabies virus (RABV), is the most fatal zoonotic disease. It is a neglected tropical disease which remains a major public health problem, causing approximately 59,000 deaths worldwide annually. Despite the existence of effective vaccines, the high incidence of human rabies is mainly linked to tedious vaccine immunisation procedures and the overall high cost of post-exposure prophylaxis. Therefore, it is necessary to develop an effective vaccine that has a simple procedure and is affordable to prevent rabies infection in humans. RABV belongs to the genus Lyssavirus and family Rhabdoviridae. Previous phylogenetic analyses have identified seven major clades of RABV in China (China I-VII), confirmed by analysing nucleotide sequences from both the G and N proteins. This study evaluated the immunogenicity and protective capacity of SYS6008, an mRNA rabies vaccine expressing rabies virus glycoprotein, in mice and cynomolgus macaques. We demonstrated that SYS6008 induced sufficient levels of rabies neutralising antibody (RVNA) in mice. In addition, SYS6008 elicited strong and durable RVNA responses in vaccinated cynomolgus macaques. In the pre-exposure prophylaxis murine model, one or two injections of SYS6008 at 1/10 or 1/30 of dosage provided protection against a challenge with a 30-fold LD50 of rabies virus (China I and II clades). We also demonstrated that in the post-exposure prophylaxis murine model, which was exposed to lethal rabies virus (China I-VII clades) before vaccination, one or two injections of SYS6008 at both 1/10 and 1/30 dosages provided better protection against rabies virus challenge than the immunization by five injections of commercial vaccines at the same dosage. In addition, we proved that SYS6008-induced RVNAs could neutralise RABV from the China I-VII clades. Finally, 1/10 of the dosage of SYS6008 was able to stimulate significant RABV-G specificity in the T cell response. Furthermore, we found that SYS6008 induced high cellular immunity, including RABV-G-specific T cell responses and memory B cells. Our results imply that the SYS6008 rabies vaccine, with a much simpler vaccination procedure, better immunogenicity, and enhanced protective capacity, could be a candidate vaccine for post-exposure prophylaxis of rabies infections.

[Intervention effects of estradiol on myocardial ischemia- reperfusion injury of rat and its mechanisms].

Objective: To study the effects of estradiol (E2) on alleviating myocardial ischemia/reperfusion(I/R) injury through estrogen receptorß(ERß) mediated extracellular regulated protein kinases(ERK) pathway activation. Methods: Eighty-four adult female SD rats were ovariectomized and randomly divided into control group, NC siRNA adeno-associated virus (AAV) group received sham operation, the myocardial I/R injury model was prepared by ligation of the left anterior descending coronary artery in I/R group, E2+I/R group, NC siRNA AAV+I/R group, NC siRNA AAV+E2+I/R group and ERß-siRNA AAV+E2+I/R group. E2+I/R group, NC siRNA AAV+E2+I/R group and ERß-siRNA AAV+E2+I/R group were treated with E2 0.8 mg/kg by gavage for 60 days before modeling. NC siRNA AAV+I/R group, NC siRNA AAV+E2+I/R group, and ERß-siRNA AAV+E2+I/R group were treated with AAV by caudal vein injection 24 h before modeling. After 120 min of reperfusion, the contents of serum lactate dehydrogenase (LDH), phosphocreatine kinase (CK), phosphocreatine kinase isoenzyme (CK-MB), myocardial infarction area and the expressions of ERß, p-ERK, the contents of tumor necrosis factor-α(TNF-α), interleukin-1ß(IL-1 ß), malondialdehyde (MDA) and total antioxidant capacity (T-AOC) in myocardium were measured. Results: The contents of serum LDH, CK, CK-MB, myocardial infarction area and the contents of TNF-α, IL-1 ß, MDA in myocardium of I/R group were higher than those of the control group, the expression levels of ERß and p-ERK and the content of T-AOC were lower than those in the control group (P＜0.05). The contents of serum LDH, CK and CK-MB, myocardial infarction area and the contents of TNF-α, IL-1 ß and MDA in myocardium of E2+I/R group were lower than those of the I/R group, the expression levels of ERß and p-ERK and the content of T-AOC were higher than those of the I/R group(P＜0.05). After knockdown ERß by caudal vein injection of ERß-siRNA AAV, the contents of serum LDH, CK and CK-MB, myocardial infarction area and the contents of TNF-α, IL-1 ß and MDA in myocardium of ERß-siRNA AAV+E2+I/R group were higher than those of NC-siRNA AAV+E2+I/R, the expression levels of ERß and p-ERK and the content of T-AOC were lower than those of NC-siRNA AAV+E2+I/R(P＜0.05). Conclusion: E2 has protective effects on myocardial I / R injury in ovariectomized rats, which are related to the promotion of ERß mediating the activation of ERK pathway, reducing inflammatory and oxidative stress responses.

Recombinant SARS-CoV-2 RBD with a built in T helper epitope induces strong neutralization antibody response.

Without approved vaccines and specific treatments, COVID-19 is spreading around the world with above 26 million cases and approximately 864 thousand deaths until now. An efficacious and affordable vaccine is urgently needed. The Val308 - Gly548 of spike protein of SARS-CoV-2 linked with Gln830 - Glu843 of Tetanus toxoid (TT peptide) (designated as S1-4) and without TT peptide (designated as S1-5) were expressed and renatured. The antigenicity and immunogenicity of S1-4 were evaluated by Western Blotting (WB) in vitro and immune responses in mice, respectively. The protective efficiency was measured preliminarily by microneutralization assay (MN50). The soluble S1-4 and S1-5 protein was prepared to high homogeneity and purity. Adjuvanted with Alum, S1-4 protein stimulated a strong antibody response in immunized mice and caused a major Th2-type cellular immunity supplemented with Th1-type immunity. Furthermore, the immunized sera could protect the Vero E6 cells from SARS-CoV-2 infection with neutralizing antibody titer 256. Recombinant SARS-CoV-2 RBD with a built in T helper epitope could stimulate both strong humoral immunity supplemented with cellular immunity in mice, demonstrating that it could be a promising subunit vaccine candidate.

Epidemiological distribution of hepatitis B virus genotypes in 1-29-year-olds in the mainland of China.

BACKGROUND: To analyze the epidemiological distribution of Hepatitis B virus (HBV) genotype in the mainland of China following the implementation of effective preventive measures. METHODS: Five hundred and seventeen HBsAg-positive subjects aged 1-29 years surveyed in the 2014 national HBV sero-survey in the mainland of China were enrolled in the study. The full-length HBV genome was obtained by PCR amplification and sequencing. The HBV genotype was determined by phylogenetic analysis. Combined with questionnaire information, HBV genotype distribution was analyzed. RESULTS: Of the 517 HBsAg-positive subjects, 369 (71.4%) were included in the analysis. HBV genotypes found were B (45.0%), C (36.6%), D (6.0%), C/D (9.8%), B/C (2.2%), and I (0.5%). Geographic differences in HBV genotype were significant for seven regions. Three serotypes were found: adw (47.2%), adr (35.5%), and ayw (17.3%). B2 (43.9%) and C2 (25.2%) were the two major subgenotypes. The predominant genotypes differed between the Han group and the other ethnic groups. No statistical differences in genotype distribution were found by gender, age group, or hepatitis B (HepB) vaccination history. CONCLUSION: The prevalence of HBV genotype B was higher than that of genotype C with subgenotypes B2 and C2 endemic in 1-29-year-olds in the mainland of China, after HBV prevalence has reduced significantly due to the implementation of preventive measures. HepB vaccination or other factors did not interfere with HBV genotype distribution. The surveillance of HBV genotype was essential for responding to the potential changes and impact on the preventive policies in the future.

The biological characteristics of SARS-CoV-2 spike protein Pro330-Leu650.

SARS-CoV-2 is the cause of the worldwide outbreak of COVID-19 that has been characterized as a pandemic by the WHO. Since the first report of COVID-19 on December 31, 2019, 179,111 cases were confirmed in 160 countries/regions with 7426 deaths as of March 17, 2020. However, there have been no vaccines approved in the world to date. In this study, we analyzed the biological characteristics of the SARS-CoV-2 Spike protein, Pro330-Leu650 (SARS-CoV-2-SPL), using biostatistical methods. SARS-CoV-2-SPL possesses a receptor-binding region (RBD) and important B (Ser438-Gln506, Thr553-Glu583, Gly404-Aps427, Thr345-Ala352, and Lys529-Lys535) and T (9 CD4 and 11 CD8 T cell antigenic determinants) cell epitopes. High homology in this region between SARS-CoV-2 and SARS-CoV amounted to 87.7%, after taking the biological similarity of the amino acids into account and eliminating the receptor-binding motif (RBM). The overall topology indicated that the complete structure of SARS-CoV-2-SPL was with RBM as the head, and RBD as the trunk and the tail region. SARS-CoV-2-SPL was found to have the potential to elicit effective B and T cell responses. Our findings may provide meaningful guidance for SARS-CoV-2 vaccine design.

Long-term protection at 20-31 years after primary vaccination with plasma-derived hepatitis B vaccine in a Chinese rural community.

Background: To assess the long-term protection conferred by plasma-derived hepatitis B vaccine at 20-31y after primary immunization during infancy in Chinese rural community.Method: Participants born between 1986 and 1996, who received a full course of primary vaccination with plasma-derived hepatitis B vaccine and had no experience with booster vaccination were enrolled. An epidemiological investigation was performed, and blood samples were collected to detect hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and hepatitis B core antibody (anti-HBc). The positive rate of HBsAg, anti-HBs, and anti-HBc were calculated to evaluate the long-term protection of the plasma-derived hepatitis B vaccine.Results: A total of 949 participants were enrolled in the final analysis. Six subjects were detected to be HBsAg-positive, resulting in a HBsAg carrier rate of 0.63% (6/949). A total of 468 (52.41%) participants maintained a level of anti-HBs antibody ≥10 mIU/mL, with a GMC of 112.20 mIU/mL (95%CI: 97.72 ~ 128.82 mIU/mL). A significant downtrend was observed in the anti-HBs positive rate (P < .001). The average anti-HBc positive rate was 5.90% (56/949), increased with prolongation of immunization (P < .001).Conclusions: The plasma-derived hepatitis B vaccine maintained satisfactory protection at 20-31 y after primary immunization. These results indicate that a booster dose is not necessary. Further studies on the immune memory induced by the plasma-derived hepatitis B vaccine are needed.

Intranasal Immunization Using CTA1-DD as a Mucosal Adjuvant for an Inactivated Influenza Vaccine.

OBJECTIVE: To evaluate the effect of intranasal immunization with CTA1-DD as mucosal adjuvant combined with H3N2 split vaccine. METHODS: Mice were immunized intranasally with PBS (negative control), or H3N2 split vaccine (3 µg/mouse) alone, or CTA1-DD (5 µg/mouse) alone, or H3N2 split vaccine (3 µg/mouse) plus CTA1-DD (5 µg/mouse). Positive control mice were immunized intramuscularly with H3N2 split vaccine (3 µg/mouse) and alum adjuvant. All the mice were immunized twice, two weeks apart. Then sera and mucosal lavages were collected. The specific HI titers, IgM, IgG, IgA, and IgG subtypes were examined by ELISA. IFN-γ and IL-4 were test by ELISpot. In addition, two weeks after the last immunization, surivival after H3N2 virus lethal challenge was measured. RESULTS: H3N2 split vaccine formulated with CTA1-DD could elicit higher IgM, IgG and hemagglutination inhibition titers in sera. Furthermore, using CTA1-DD as adjuvant significantly improved mucosal secretory IgA titers in bronchoalveolar lavages and vaginal lavages. Meanwhile this mucosal adjuvant could enhance Th-1-type responses and induce protective hemagglutination inhibition titers. Notably, the addition of CTA1-DD to split vaccine provided 100% protection against lethal infection by the H3N2 virus. CONCLUSION: CTA1-DD could promote mucosal, humoral and cell-mediated immune responses, which supports the further development of CTA1-DD as a mucosal adjuvant for mucosal vaccines.

Immune persistence 17 to 20 years after primary vaccination with recombination hepatitis B vaccine (CHO) and the effect of booster dose vaccination.

BACKGROUND: To assess the immune persistence conferred by a Chinese hamster ovary (CHO)-derived hepatitis B vaccine (HepB) 17 to 20 years after primary immunization during early life. METHODS: Participants born between 1997 and 1999 who received a full course of primary vaccination with HepB (CHO) and who had no experience with booster vaccination were enrolled. Blood samples were required from each participant for measurement of hepatitis B surface antibody (anti-HBs), surface antigen and core antibody levels. For those who possessed an anti-HBs antibody < 10 mIU/mL, a single dose of HepB was administered, and 30 days later, serum specimens were collected to assess the booster effects. RESULTS: A total of 1352 participants were included in this study. Of these, 1007 (74.5%) participants could retain an anti-HBs antibody ≥10 mIU/mL, with a geometric mean concentration (GMC) of 57.4 mIU/mL. HBsAg was detected in six participants, resulting in a HBsAg carrier rate of 0.4% (6/1352). Of those participants with anti-HBs antibodies < 10 mIU/mL, after a challenge dose, 231 (93.1%) presented an anti-HBs antibody ≥10 mIU/mL, with a GMC of 368.7 mIU/mL. A significant increase in the anti-HBs positive rate (≥ 10 mIU/mL) after challenge was observed in participants with anti-HBs antibodies between 2.5 and 10 mIU/mL and participants boosted with HepB (CHO), rather than those with anti-HBs antibodies < 2.5 mIU/mL and those boosted with HepB (SC). CONCLUSION: Since satisfactory immune protection against HBV infection conferred by primary vaccination administered 17-20 years ago was demonstrated, there is currently no urgent need for booster immunization.

Intranasal vaccination with ebola virus GP amino acids 258-601 protects mice against lethal challenge.

Ebola virus (EBOV) disease (EVD) leads to lethal hemorrhagic fever with a case fatality rate as high as 90%, thus posing a serious global public health concern. However, while several vaccines based on the EBOV glycoprotein have been confirmed to be effective in animal experiments, no licensed vaccines or effective treatments have been approved since the first outbreak was reported in 1976. In this study, we prepared the extracellular domain of the EBOV GP protein (designated as N20) by prokaryotic expression and purification via chromatography. Using CTA1-DD (designated as H45) as a mucosal adjuvant, we evaluated the immunogenicity of N20 by intranasal administration and the associated protective efficacy against mouse-adapted EBOV challenge in mice. We found that intranasal vaccination with H45-adjuvanted N20 could stimulate humoral immunity, as supported by GP-specific IgG titers; Th1 cellular immunity, based on IgG subclasses and IFN-γ/IL-4 secreting cells; and mucosal immunity, based on the presence of anti-EBOV IgA in vaginal lavages. We also confirmed that the vaccine could completely protect mice against a lethal mouse-adapted EBOV (MA-EBOV) challenge with few side effects (based on weight loss). In comparison, mice that received N20 or H45 alone succumbed to lethal MA-EBOV challenge. Therefore, mucosal vaccination with H45-adjuvanted N20 represents a potential vaccine candidate for the prevention of EBOV in an effective, safe, and convenient manner.

A new dual-targeting real-time RT-PCR assay for hepatitis D virus RNA detection.

In this study, a real-time reverse transcription-polymerase chain reaction (real time RT-PCR) assay targeting 2 genetic segments was established to detect HDV RNA. Utilizing the World Health Organization International Standard for Hepatitis D Virus RNA, the lower limit of detection was 575 IU/mL, and the linearity of quantification ranged from 575,000 IU/mL to 575 IU/mL. 384 HBsAg-positive samples collected from China were tested by this method and HDV antibody detection. Eleven samples were positive for anti-HDV IgG which may persist after HDV resolution, 6 samples were HDV RNA positive, and 5 samples were positive for anti-HDV IgM. This assay showed more sensitivity than the detection of anti-HDV IgM. These data demonstrate that the real-time RT-PCR assay for HDV RNA could be implemented in the clinical detection of HDV infection in chronic HBV-infected patients in China.

Efficient Humoral and Cellular Immune Responses Induced by a Chimeric Virus-like Particle Displaying the Epitope of EV71 without Adjuvant.

OBJECTIVE: To eliminate the side effects of aluminum adjuvant and His-tag, we constructed chimeric VLPs displaying the epitope of EV71 (SP70) without His-tagged. Then evaluating whether the VLPs could efficiently evoke not only humoral but also cellular immune responses against EV71 without adjuvant. METHODS: The fusion protein was constructed by inserting SP70 into the MIR of truncated HBcAg sequence, expressed in E. Coli, and purified through ion exchange chromatography and density gradient centrifugation. Mice were immunized with the VLPs and sera were collected afterwards. The specific antibody titers, IgG subtypes and neutralizing efficacy were detected by ELISA, neutralization assay, and EV71 lethal challenge. IFN-γ and IL-4 secreted by splenocytes were tested by ELISPOT assay. RESULTS: HBc-SP70 proteins can self-assemble into empty VLPs. After immunization with HBc-SP70 VLPs, the detectable anti-EV71 antibodies were effective in neutralizing EV71 and protected newborn mice from EV71 lethal challenge. There was no significant difference for the immune efficacy whether the aluminum adjuvant was added or not. The specific IgG subtypes were mainly IgG1 and IgG2b and splenocytes from the mice immunized produced high levels of IFN-γ and IL-4. CONCLUSION: The fusion proteins without His-tagged was expressed and purified as soluble chimeric HBc-SP70 VLPs without renaturation. In the absence of adjuvant, they were efficient to elicit high levels of Th1/Th2 mixed immune response as well as assisted by aluminum adjuvant. Furthermore, the chimeric VLPs have potential to prevent HBV and EV71 infection simultaneously.

Hepatitis B Immunoprophylactic Failure and Characteristics of the Hepatitis B Virus Gene in Mother-Infant Pairs in Parts of China.

OBJECTIVE: To determine the hepatitis B immunoprophylactic failure rate in infants born to hepatitis B virus (HBV) infected mothers and to characterize HBV genes. METHODS: HBV-serological testing was conducted for pregnant women and infants. The complete genomes of 30 HBV isolates were sequenced, and genetic characteristics were analyzed using MEGA 5 software. RESULTS: The immunoprophylactic failure rate for infants who had completed the scheduled hepatitis B vaccination program was 5.76% (32/556). High sequence homology (99.8%-100%) was observed in 8 of the 10 mother-infant pairs. We identified 19 subgenotype C2 strains, 9 subgenotype B2 strains, and 2 subgenotype C1 strains. Three serotypes were detected: adr (19/30), adw (9/30), and ayw (2/30). The frequency of amino acid mutation of the 'a' determinant region was 16.67% (5/30), including that of Q129H, F134Y, S136Y, and G145E. We detected 67 amino acid mutations in the basal core promoter, precore, and core regions of the genome. CONCLUSION: The immunoprophylactic failure rate in infants born to HBV-infected mothers is low in the regions of China examined during this study. Moreover, HBV mutation in the 'a' determinant region could not account for immunoprophylactic failure for all infants.

Expression and Purification of Recombinant Hepatitis Delta Virus (HDV) Antigen for Use in a Diagnostic ELISA for HDV Infection Using the High-Density Fermentation Strategy in Escherichia coli.

OBJECTIVE: Hepatitis Delt a Virus (HDV) antigen is widely used as a capture antigen in ELISAs for the identification of HDV infection; large amounts of recombinant HDV antigen with active antigenicity are required for this purpose. METHODS: Reconstruct the gene of HDV antigen based on the bias code of Escherichia coli, the recombinant protein expresses by high-density fermentation with fed-batch feeding strategy, and purify by immobilized metal chromatography. The sensitivity and specificity of this antigen detect by ELISA method. RESULTS: The expression of HDV antigen can reach 20% of the total cell mass in the soluble form. The recombinant HDV antigen can be conveniently purified (98%) by immobilized metal ion affinity chromatography (IMAC) using the interaction between a His-tag and nickel ions. Production of recombinant HDV antigen can reach 0.5 g/L under conditions of high-density cell fermentation. Applied to the diagnostic ELISA method, the recombinant HDV antigen shows excellent sensitivity (97% for IgM and 100% for IgG) and specificity (100% for IgG and IgM) for the detection of anti-HDV antibodies. CONCLUSION: Expression and purification the recombinant HDV antigen as a candidate protein for application in a diagnostic ELISA for HDV infection. Large-scale production of the protein can be achieved using the high-density fermentation strategy.

Evolution and genetic characterization of hepatitis A virus isolates in China.

OBJECTIVES: Hepatitis A virus (HAV), transmitted mainly through the fecal-oral route, is one of the major causes of acute viral hepatitis worldwide. HAV is endemic in China. This study performed genetic and evolutionary analysis of HAV isolates circulated in the country. METHODS: Clinical samples were collected and HAV nucleotide and deduced amino acid sequences were analyzed. 70 representative sequences of HAV VP3-VP1-2A regions sampled from 1988 to 2014 were compared and characterized using the Bayesian Markov Chain Monte Carlo approach (BEAST software, Version1.7.5). RESULTS: All isolates from China in this study belonged to genotype I, with most of the samples clustering in subgenotype IA, while several unique amino acid variants were observed. The estimated mean substitution rate was 5.56×10(-4) substitutions / site / year, the time to the most recent common ancestor of genotype I isolates in China was calculated to be around 180 years ago. Skyline plots showed the incidence of HAV went down gradually from the mid-1990s. CONCLUSIONS: The evolution estimations were consistent with the laboratory and epidemiological results. Several isolates from China showed amino acid changes close to the immunodominant sites, which needs to be further analyzed. The study results have indicated the effectiveness of improving economic and sanitation levels together with HAV vaccination to control HAV-related infections in China.

[Construction of cDNA infectious clones of EV71 highly-pathogenic and cell-culture-adapted strains].

The highly-pathogenic EV71 strain is the primary cause of mortality in hand-foot-and-mouth disease (HFMD) associated with neurological symptoms, for which no clinically effective drugs or vaccines exist. This study aimed to construct infectious cDNA clones of the EV71 highly-pathogenic strain and the cell-culture adapted strain using a reverse genetics approach. The genomic RNAs of EV71 parent strains were used as the templates for RT-PCR amplification, and then the PCR products that overlapped the full-length genome were connected into the pBR322 vector to produce infectious clones of pEV71 (HP) and pEV71 (CCA), respectively. The results showed that the HP strain propagated much more quickly than the CCA strain. The rescued viruses derived from the infectious clones not only maintained their consistency with their parent strains in terms of genomic sequences, but also retained their respective biological phenotypes. This research will contribute to our understanding of EV71 pathogenesis and the development of novel vaccines against HFMD.

[Prokaryotic soluble expression of protein D of Haemophilus influenzae type b].

OBJECTIVE: To express the recombinant D protein in prokaryotic expression system solubly and make preparation for producing D-carrier conjugate vaccine next step. METHODS: The hpd gene fragment removed of signal peptide from genomic DNA of Hib CMCC was inserted into pET43. 1a. The recombinant plasmid was transformed to competent E. coli BL21 (DE3) for expression under induction of IPTG. The expressed recombination protein was precipitated with ammonium sulfate, purified by DEAE anion exchange column chromatography and identified for reactogenicity by Western Blot. RESULTS: The expressed recombination protein, in a soluble form, constained about 50% of total somatic protein and showed specific reaction with the HIB antisera after preliminary purification. CONCLUSION: The D protein recombined expression plasmid was constructed successfully and expressed D protein in prokaryotic cells in a solube form.

[Study on the risk of HBV infection among spouses of HBsAg carriers].

OBJECTIVE: To investigate the risk of HBV infection among the spouses of hepatitis B virus surface antigen (HBsAg) carriers and to provide a reference for developing strategies on hepatitis B control and prevention. METHODS: A case-control study including HBsAg carriers aged 20 - 45 years-old from the nationwide sero-epidemiological survey for Hepatitis B in both Guangdong and Jiangxi provinces in 2006, together with their spouses were selected as case group, while. HBsAg negative persons and their spouses were among the control groups, under the same residential areas, gender, age and age of marriage to the HBsAg carriers. Questionnaire survey and hepatitis B serological markers detection were carried out, together with the HBV genotype detection among the HBsAg positive couples between husband and wife by PCR. RESULTS: Among the spouses of HBsAg carriers, the positive rate of HBsAg was 13.21%, while the rate was 6.29% for the spouse of HBsAg negative population, with difference statistically significant (χ² = 4.23, P < 0.05). HBsAg positive rate among spouses of the case group was higher than that in the control group. Among the spouses of HBsAg carriers, the HBsAg rate was positively correlated with the age of marriage, frequency of sexual intercourse and condom use. There were 21 pairs of HBsAg carriers between husband and wife, and HBV were isolated among 13 pairs, and there were 11 pairs carrying the same HBV genotype, accounting for 84.62%. HBV genotypes would include 8 pairs of type B and 3 pairs of type C. However, only 2 pairs were infected with different HBV genotype. CONCLUSION: High risks of HBV infection existed in the spouses of HBsAg carriers. It was important to ask the HBsAg carriers to take the initiative in informing their spouses, and carrying out the appropriate measures, such as safe sex or timely hepatitis B vaccination for the spouse of HBsAg carriers etc., so as to reduce the HBV transmission between husband and wife.

[Prokaryotic expression and characterization of two recombinant receptor-binding domain(RBD) proteins of human coronavirus NL63(HcoV-NL63)].

The receptor-binding domain(RBD) protein of HCoV-NL63 is a major target in the development of diagnostic assay and vaccine, it has a pivotal role in receptor attachment, viral entry and membrane fusion. In this study, we prepared 2 purified recombinant HCoV-NL63 RBD proteins using in E. coli system and identified the proteins by Western blotting. We first optimized codon and synthesized the RL (232-684aa)coding gene, then amplified the RL or RS(476-616aa) coding gene via PCR using different primers . The RL or RS coding gene was cloned into the pM48 expression vector fused with TrxA tag. The RBD (RL and RS) of HCoV-NL63 were expressed majorly as inclusion body when expressed in E. coli BL21pLys S under different conditions. The expressed products were purified by affinity chromatography then analyzed by SDS-PAGE and Western blotting. Our results showed that the recombinant RBD proteins were maximally expressed at 37 degrees C with 0. 8mM IPTG induction for 4h. RL or RS protein with 95 % purity was obtained and reacted positively with anti-sera from mice immunized with the recombinant vaccinia virus (Tiantan strain) in which HCoV-NL63 RL or RS protein was expressed. In conclusion, the purified recombinant RBD proteins(RL and RS)derived from E. coli were first prepared in China and they might provide a basis for further exploring biological role and vaccine development of HCoV-NL63.

[Construction of recombinant CHO cell strain for high expression of HBsAg].

OBJECTIVE: To overexpress hepatitis B virus S gene in CHO cells cultured in serum-free media. METHOD: Plasmid was constructed by cloning of HBV S gene and then it was transfected into CHO cells. After cell screen, the positive clones were identified and isolated into a serum-free media followed by the serological and morphological characterization of the expression product. RESULT: CHO cell strains which can express HBsAg efficiently and stably were obtained. Spherical and filamentous HBsAg could be detected under electronic microscope. The titer of the expression product was up to 1:5000. CONCLUSION: Serum-free media cultured CHO cell strain for overexpression of HBsAg was successfully constructed and the expression product was high antigenic.