OBJECTIVETo investigate the characteristics and dynamic changes of serum neutralizing antibody response in patients with primary infection of dengue virus type 1 (DENV-1).

METHODSSerum samples were obtained from the same patients with primary infection of DENV-1 within 2 weeks after symptom onset in 2006 and in 2010. A group-specific DENV NS1 capture ELISA-based micro-neutralizing test (ELISA-MNT) capable of detecting neutralizing antibodies against all the 4 serotypes of DENV was used to test the neutralizing antibody titers against DENV in the serum samples. The neutralizing antibody titers against a standard strain and 2 clinically isolated strains of DENV-1 were detected in serum samples collected in 2010.

RESULTSCross-reactive neutralizing antibody response against all the 4 serotypes of DENV was found in both of the serum samples collected in 2006 and 2010, but the samples collected in 2006 showed stronger cross-reactive neutralizing antibody responses. The neutralizing antibody against DENV-2, rather than the anticipated DENV-1 antibody, had the highest titer in the samples collected in 2006, whereas the antibody against homologous DENV-1 had the highest titer in the samples obtained in 2010. The neutralizing antibody titers against the homologous DENV-1 was significantly higher in samples collected in 2010 (U=86.500, P=0.000), which also demonstrated significantly different neutralizing antibody titers against the 3 different strains of DENV-1 (Χ(2)=12.123, P=0.002).

CONCLUSIONThe production of cross-reactive neutralizing antibodies between the 4 serotypes of DENV is a characteristic of DENV infection, particularly during early infection, but only the homologous neutralizing antibody increases obviously over time. The titers of the neutralizing antibodies against different strains, even of the same serotype, may differ distinctly.

Antibodies, Neutralizing ; blood ; Antibodies, Viral ; blood ; Cross Reactions ; Dengue ; blood ; immunology ; Dengue Virus ; classification ; immunology ; Humans ; Neutralization Tests

OBJECTIVESHuman metapneumovirus (hMPV) has been identified as one of the most important viral pathogens for acute respiratory tract infections in children. This study was to observe neutralizing activity to hMPV in sera collected from children without respiratory illnesses aged 0 to 6 years and to investigate the correlation between the level of hMPV IgG antibody and neutralizing activity in the same serum.

METHODSSera of 0 to 3 years old children were collected from patients hospitalized for surgery without documented respiratory illnesses, and sera of 3 to 6 years old children were remainder of serum specimens taken for health checkup. Total number of serum specimens was 325. Ten serum samples were selected for neutralizing activity detection in every age group and the sum was 50. The neutralizing titer was assessed by microneutralization assay which had been well documented previously.

RESULTSAmong 50 serum samples, eight in which hMPV IgG antibody was proved negative by ELISA previously did not show any neutralizing activity. The remaining 42 samples, as expected, showed variable neutralizing activity. The geometric mean neutralizing titer to hMPV for all the samples was 1:129. In the age group of 0-5 months, the geometric mean titer was 1:160. In the age groups of 6-11 months, 12-23 months, 24-35 months, 3-6 years, the geometric mean titers were 1:58.9, 1:114.9, 1:172.8 and 1:160.0, respectively. The level of hMPV antibody and neutralizing activity in the same serum was significantly correlated (r = 0.668).

CONCLUSIONMost 0-6 year-old children in Chongqing area have neutralizing antibody in their serum. Whether such neutralizing activity is high enough to prevent infection with different subtypes of hMPV is unknown.

Antibodies, Neutralizing ; blood ; immunology ; Antibodies, Viral ; blood ; Child ; Child, Preschool ; China ; Enzyme-Linked Immunosorbent Assay ; Humans ; Metapneumovirus ; immunology ; Paramyxoviridae Infections ; blood ; immunology ; Pediatrics ; Respiratory Tract Infections ; immunology

OBJECTIVETo construct a recombinant human adenovirus type 5 (Ad5) expressing luciferase and GFP reporter gene and detect neutralizing antibodies against adenovirus type 5 in common marmosets (Callithrix jacchus) to provide basic laboratory data for evaluating adenovirus vaccines.

METHODSLuciferase and GFP reporter genes from plasmid pHAGE-CMV-GFP were inserted into pDC315 to construct the recombinant adenovirus shutter plasmid pDC315-Luc-GFP. The shutter plasmid was co-transduced with pBHGlox(delta)E1,3Cre in 293A cell line to package the recombinant adenovirus rAd5/Luc/GFP. Three rounds of plaque formation experiment were performed to select the monoclonal adenovirus followed by purification with cesium chloride density gradient centrifugation and virus titration with TCID50 method. Chemiluminescence assay and flow cytometry were employed to detect the neutralizing antibody levels in 14 common marmosets.

RESULTSThe shuttle plasmid pDC315-Luc-GFP was successfully constructed and the recombinant adenovirus rAd5/Luc/GFP was packaged with a the titer reaching 6.9×10(11.5) PFU/mL. In the 14 marmosets, chemiluminescence assay identified 4 (28.6%) marmosets that were positive for Ad5-neutralizing antibodies, including 2 with a antibody titer of 1/16 and another 2 with a titer of 1/32; flow cytomery detected Ad5-neutralizing antibodies in 3 marmosets at the titer of 1/16.

CONCLUSIONChemiluminescence assay is a simple, sensitive, and accurate modality for detecting Ad5-neutralizing antibodies. Common marmosets have a very low positivity rate for Ad5-neutralizing antibodies and are therefore promising models for studying adenovirus-based vaccines and therapies.

Adenoviruses, Human ; immunology ; Animals ; Antibodies, Neutralizing ; blood ; Antibodies, Viral ; blood ; Callithrix ; Cell Line ; Humans ; Immunity, Humoral ; Luciferases ; Plasmids

BACKGROUNDEnterovirus 71 (EV71) and coxsackievirus A16 (Cox A16) are major causative agents for hand, foot and mouth disease (HFMD). Studies indicate that the frequent HFMD outbreaks result in a few hundreds children's death in China in recent years. The vaccine and other research for HFMD need to be developed urgently.

THE AIMS OF OUR STUDY WEREto explore dynamic development of mother-source neutralizing antibodies against EV71 and Cox A16 in infants from Jiangsu Province, China, and to provide the fundamental data for further establishing of corresponding immunization course.

METHODSPeripheral blood samples were collected from 133 of parturient women once immediately before delivery and their infants at two and seven months of age. Method of micro-dose cytopathogenic effect was used to measure neutralizing antibodies against EV71 and Cox A16, respectively.

RESULTSSeropositive rates of anti-EV71 and anti-Cox A16 in prenatal women were 79.7% (106/133) and 92.5% (123/133), respectively; geometric mean titers (GMTs) were 29.0 and 61.9; 75.9% (101/133) prenatal women were both positive in anti-EV71 and anti-Cox A16; seropositive rates of anti-EV71 and anti-Cox A16 were 25.6% (34/133) and 38.3% (51/133) in infants at two months of age; GMTs were 12.3 and 18.0, respectively. GMTs of anti-EV71 were significantly higher for infants at seven months (82.6) compared with that at two months (P < 0.05), showing infants had inapparently infected by EV71 during two to seven months. Although only one offspring (0.75%) at seven months was found having anti-Cox A16 transfered from maternal, this observation suggested no maternal antibody may remain in infants at seven months.

CONCLUSIONSThe prevalence of EV71 and Cox A16 were relatively high in Jiangsu Province. Bivalent vaccine against both EV71 and Cox A16 should be developed, and the ideal time point for prime immunization for infants is around 2-5 months of age.

Antibodies, Neutralizing ; blood ; immunology ; Cells, Cultured ; Enterovirus ; immunology ; Enterovirus A, Human ; immunology ; Female ; Hand, Foot and Mouth Disease ; immunology ; virology ; Humans ; Infant ; Infant, Newborn

BACKGROUNDThe adenovirus-based HIV-1 vaccine developed by Merck Company suffered from an unexpected failure in September 2007. This generated a big shift in the strategy of HIV vaccine development with renewed focus on the induction of neutralizing antibodies. A major challenge in developing an HIV-1 vaccine is to identify immunogens and adopt delivery methods that can elicit broadly neutralizing antibodies against primary isolates of different genetic subtypes.

METHODSMost circulating HIV-1 isolates in China are composed of clades Thai-B, CRF_BC and CRF01_AE. In order to construct DNA vaccines against these 3 HIV-1 subtypes, DNA vaccines carrying the gp120 regions from HIV-1 isolates of GX48(AE), GX79(AE), NX22(BC), GS22(BC), HN24(Thai-B) were constructed. Expression of gp120 from these DNA vaccines was detected by Western blotting in transiently transfected 293T cells. Pilot immunizations of New Zealand white rabbits were performed using the strategy of "DNA prime plus protein boost" and the neutralizing antibody response was detected in a Tzm-bl cell based assay against different HIV-1 strains.

RESULTSResponse of gp120-specific antibody was relatively low after DNA primes (mean titer = 10(4.72)); however, the titer of gp120-specific antibody went up with 2 protein boosts (mean titer = 10(6.81)). Above all, neutralizing antibody (Nab) titers induced by this combined approach were much better than those elicited by DNA or protein used alone (P < 0.01). Neutralizing activities of immunized rabbit sera against several pseudoviruses and laboratorial strains were evaluated, most rabbit sera primed with monovalent vaccine were capable of neutralizing only 1 of 5 viruses, however, sera primed with the polyvalent DNA vaccines were able to neutralize at least 2 of 5 viruses.

CONCLUSIONPolyvalent DNA prime plus protein boost is an effective immunization strategy to broaden the neutralization breadth and further research should be performed on the basis of this pilot study.

AIDS Vaccines ; immunology ; Animals ; Antibodies, Neutralizing ; blood ; Female ; HIV Envelope Protein gp120 ; genetics ; immunology ; Humans ; Immunization ; Immunoglobulin G ; blood ; Phylogeny ; Rabbits ; Vaccines, DNA ; immunology

OBJECTIVETo evaluate the enterovirus 71 (EV 71) protective antibody level of health adults people in Beijing.

METHODSSerum samples and information of participants were collected from hospitals in Beijing. EV71 IgG was tested by enzyme-linked immunoadsordent assay (ELISA). EV 71 neutralization antibody was evaluated by micro-cytopathic effect neutralization test (MCPENT).

RESULTS486 participants were enrolled. Age range was 19-62 years old. The average EV 71 IgG positive rate was 40. 3% , there are no significant difference between the EV 71 IgG positive rate of male and female. The rate of EV 71 neutralization antibody which title high than 1:256 is 13.3%. The rate of EV 71 IgG and the titile of EV 71 neutralization antibody are decreasing by the age.

CONCLUSION40% of health adults of Beijing area have EV71 protective antibody. But the title higher than 1:256 is only 13.3%. EV 71 protective antibody decreases significantly with the age.

Adult ; Age Factors ; Antibodies, Neutralizing ; blood ; Antibodies, Viral ; blood ; China ; Enterovirus A, Human ; immunology ; isolation & purification ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Immunoglobulin G ; blood ; Male ; Middle Aged

OBJECTIVETo explore the neutralization capacities of different types of human serum to measles virus epidemic strains and vaccine strain.

METHODSNeutralization antibody (NT) to Shanghai 191 and measles virus isolates in 2005 were tested using acute and convalescent serum samples from diagnosed measles patients, children serum samples collected before and after vaccination and serum samples of migrant residents, from 3 different regions. Additionally, animal immune serum referring to vaccine strain and 3 epidemic strains were prepared and used to undergo crossing neutralization test with corresponding strains mentioned-above. Antigenic ratios were calculated.

RESULTSGMT value of NT of after-immune serum to vaccine strains was 50.82,1.86 times higher than that to MVi/ZJ/05/7 (GMT was 27.35), whereas GMT value of convalescent serum to MVi/ZJ/05/7 (GMT was 386.95) was obviously higher than that to vaccine strain (GMT was 1:151.83),and GMT value of migrant residents' serum in 3 regions to MVi/ZJ/05/7 were 2.22-4.17 times lower than that to vaccine strain. Meanwhile,the antigenic ratios between MVi/ZJ/ 99/1, MVi/ZJ/04/1, MVi/ZJ/05/7 and vaccine strain were found to be 4.28,5.24 and 5.66 respectively. Additionally,low NT titers to vaccine strain were found in patients' acute sera and GMT value was over 1:4.

CONCLUSIONThere were obvious differences on neutralization antibody of different types of serum to measles vaccine strain and epidemic strains which indicating the antigenic diversity of epidemic strains had influenced the protective effectiveness of vaccine antibody to epidemic strains. It was of significance to carry on research projects on the antigenic diversity and effectiveness of measles vaccine.

Animals ; Antibodies, Neutralizing ; blood ; immunology ; Antibodies, Viral ; blood ; immunology ; Antigens, Viral ; genetics ; immunology ; Child ; China ; epidemiology ; Humans ; Measles ; epidemiology ; immunology ; prevention & control ; Measles Vaccine ; immunology ; Measles virus ; genetics ; Neutralization Tests ; Vaccination

OBJECTIVETo analyze the prevalence characteristics and influence factors of Japanese encephalitis (JE) neutralizing antibody in healthy people.

METHODSXinyang and Luoyang is the two cities in Henan Province. In 2010, healthy people of these two cities were selected by random sampling method to eight age groups: less than one year old, 1 -2 years old, 3 -4, 5 -6, 7 -14, 15 -19, 20 -59,and above 60 years old, their blood specimens were collected in May before JE infection and in November after JE infection, then followed with epidemiological investigation for JE neutralizing antibody by MCPENT.

RESULTS519 healthy people were surveyed, 1008 effective blood specimens were collected and tested. The JE neutralizing antibody positive rate was 59.52% in men, and 67.39% in male, these two rates had no statistical significance (chi2 = 3.41, P > 0.05). The JE neutralizing antibody was 58.66% in May, and 61.20% in November, these two rates had no statistical significance (chi2 = 0.68, P > 0.05). The JE neutralizing antibody positive rate of 0 - 14 years old age group was 55.19% in Xinyang, and 45.03% in Luoyang,these two rates had no statistical significance (chi2 = 3.53, P > 0. 05). The JE neutralizing antibody positive rate of above 15 years old age group is 97.78% in Xinyang,and 48.94% in Luoyang, these two rates had statistical significance (chi2 = 55.42, P < 0.05). The JE neutralizing antibody positive rate of JE vaccination was 56.85%, and 38.35% in no JE vaccination, these two rates had statistical significance (chi2 = 10.88, P < 0.05).

CONCLUSIONThe JE neutralizing antibody positive rate was showing significant differences in people above 15 years old between Xinyang and Luoyang. The JE neutralizing antibody positive rate was showing significant differences between JE vaccination and no vaccination. Xinyang and Luoyang City, recommended strengthening the 0 - 14 year-olds immunized, and at the same time, exploring and paying attention to JE immunization strategy of people above 15 years old in Luoyang.

Adolescent ; Adult ; Aged ; Antibodies, Neutralizing ; blood ; Antibodies, Viral ; blood ; Child ; Child, Preschool ; China ; Encephalitis Virus, Japanese ; immunology ; Female ; Humans ; Infant ; Male ; Middle Aged

OBJECTIVETo evaluate the immunogenicity and safety of a boost dose of inactivated polio vaccine (IPV) among children aged 18 months who had been administered with primary doses of IPV.

METHODSForm 2011 to 2012, a total of 97 children were enrolled in the present study who were vaccinated with IPV at 2, 3, 4 months of age and boosted with the same vaccine at 18 months of age. Anti-poliovirus neutralizing antibody titers in serum were measured before and after booster vaccination, geometric mean titers (GMT) and seroprotection rate were calculated. Adverse events occurring within 30 days after booster vaccination were observed, including pain, redness/swelling and induration at the injection site, fever, vomit, abnormal crying, drowsiness, loss of appetite, irritability, and all other physical discomfort and related medications were also recorded. A descriptive analysis was performed for the safety assessment.

RESULTSImmunogenicity was assessed in 84 subjects. The pre-booster seropositivity rates of neutralizing antibody against poliovirus type 1, 2, 3 before booster were all 100% (84/84) and the corresponding GMT (95% CI) was 1: 148.5 (116.49-189.29) , 1: 237.68 (178.39-316.67) and 1: 231.87 (181.27-296.58) , respectively. The seropositivity rates of neutralizing antibody against the three types of poliovirus after booster were all 100% (84/84) and the corresponding GMT (95% CI) was 1: 1612.14 (1470.57-1767.34) , 1: 1854.92 (1715.83-2005.29) and 1: 1625.50 (1452.12-1819.58) , respectively. The pre-booster titer of neutralizing antibody against poliovirus type 1, 2, 3 mainly ranged 1: 128-1: 512, which accounted for 65% (55/84) , 55% (46/84) , 74% (62/84) in each type. After the booster immunization, titers of neutralizing antibody against type 1, 2, 3 were increased as subjects with titer ≥ 1: 1024 accounted for 94% (78/84) , 95% (80/84) , 92% (77/84) , respectively.Safety was evaluated in 96 subjects, of which 16 subjects reported adverse events with the rate of 17%. The observed local events were mainly tenderness 3% (3/96) , redness/swelling and induration were not reported. The systemic adverse events included loss of appetite (8%, 8/96) , irritability (8%, 8/96) , fever (7%, 7/96) , abnormal crying (6%, 6/96) , drowsiness (6%, 6/96) and vomit (1%, 1/96) . All reported adverse events were mild or moderate. All of the local events occurred in the day of vaccination and lasted for 1-2 days, while systemic events almost developed within 2 days after vaccination and last less than 3 days.

CONCLUSIONIPV booster dose has good immunogenicity and safety profile, which provides effective protection against poliovirus.

Antibodies, Neutralizing ; blood ; Antibodies, Viral ; blood ; China ; Female ; Humans ; Immunization, Secondary ; adverse effects ; Infant ; Male ; Poliomyelitis ; prevention & control ; Poliovirus Vaccine, Inactivated ; adverse effects ; immunology ; therapeutic use

Recombinant adeno-associated virus (rAAV) serotype 2, 3 and 8 vectors are the most promising liver-tropic AAV serotype vectors. Liver diseases are significant problems in China. However, to date, few studies on AAV neutralizing antibodies (Nabs) were working with the Chinese population or with the rAAV3 vectors. The present study aimed to determine the prevalence of Nabs in Chinese population against wild-type AAV2, AAV3 and AAV8 capsids as well as additional two AAV3 variants. In addition, we performed a preliminary analysis to investigate the potential influence of traditional Chinese medicine body constitutions on AAV Nabs. Our work demonstrated that the majority of healthy Chinese subjects were positive for AAV Nabs, with the order of AAV2>AAV3=AAVLK03>AAV8. There was no difference between: 1) AAV3 and its variants; 2) male and female subjects; and 3) different age cohorts (≤35, 36-50, and ≥51 years old). People in the Qi-deficiency constitution had significantly increased AAV8 Nabs than people in the Gentleness constitution. Our studies may have impact on the future clinical design of AAV-based gene therapy in the Chinese population.
Adult ; Aged ; Antibodies, Neutralizing ; blood ; Antibodies, Viral ; blood ; Body Constitution ; Dependovirus ; classification ; immunology ; Female ; Genetic Vectors ; Humans ; Liver ; virology ; Male ; Middle Aged ; Serogroup