Plasma Metabonomics of Human Adenovirus-infected Patients with Pneumonia and Upper Respiratory Tract Infection

Objective Human adenovirus(HAdV)infection is common and can develop to serious conditions with high mortality,yet the mechanism of HAdV infection remains unclear.In the present study,the serum metabolite profiles of HAdV-7-infected patients with pneumonia or upper respiratory tract infection(URTI)were explored.Methods In total,35 patients were enrolled in the study following an outbreak of HAdV-7 in the army,of whom 14 had pneumonia and 21 had URTI.Blood samples were collected at the acute stage and at the recovery stage and were analyzed by untargeted metabolomics.Results Over 90% of the differential metabolites identified between the pneumonia patients and URTI patients were lipids and lipid-like molecules,including glycerophospholipids,fatty acyls,and sphingolipids.The metabolic pathways that were significantly enriched were primarily the lipid metabolism pathways,including sphingolipid metabolism,glycerophospholipid metabolism,and linoleic acid metabolism.The sphingolipid metabolism was identified as a significantly differential pathway between the pneumonia patients and URTI patients and between the acute and recovery stages for the pneumonia patients,but not between the acute and recovery stages for the URTI patients.Ceramide and lactosylceramide,involved in sphingolipid metabolism,were significantly higher in the pneumonia patients than in the URTI patients with good discrimination abilities[area under curve(AUC)0.742 and 0.716,respectively;combination AUC 0.801].Conclusion Our results suggested that HAdV modulated lipid metabolism for both the patients with URTI and pneumonia,especially the sphingolipid metabolism involving ceramide and lactosylceramide,which might thus be a potential intervention target in the treatment of HAdV infection.

ADV36 adipogenic adenovirus in human liver disease

obesity and liver steatosis are usually described as related diseases.obesity is regarded as exclusive consequence of an imbalance between food intake and physical exercise,modulated by endocrine and genetic factors.Non-alcoholic fatty liver disease(NAFLD),is a condition whose natural history is related to,but not completely explained by over-nutrition,obesity and insulin resistance.There is evidence that environmental infections,and notably adipogenic adenoviruses(ADV)infections in humans,are associated not only with obesity,which is sufficiently established,but also with allied conditions,such as fatty liver.In order to elucidate the role,if any,of previous ADV36 infection in humans,we investigated association of ADV36-ADV37 seropositivity with obesity and fatty liver in humans.Moreover,the possibility that lifestyle-nutritional intervention in patients with NAFLD and different ADV36 seropositive status,achieves different clinical outcomes on ultrasound bright liver imaging,insulin resistance and obesity was challenged.ADV36 seropositive patientshave a more consistent decrease in insulin resistance,fatty liver severity and body weight in comparison with ADV36 seronegative patients,indicating a greater responsiveness to nutritional intervention.These effects were not dependent on a greater pre-interventional body weight and older age.These results imply that no obvious disadvantage-and,seemingly,that some benefit-is linked to ADV36 seropositivity,at least in NAFLD.ADV36 previous infection can boost weight loss and recovery of insulin sensitivity under interventional treatment.

Construction of recombinant adeno-associated viral vectors in human neurenergen-3 gene

BACKGROUND： Research of transgene brings hope for gene therapy of various diseases; in addition, some projects have been tested in clinic. Recently, the focus has been to find an ideal vehicle and a suitable therapeutic gene. OBJECTIVE： To explore an effective way to construct recombinant adeno-associated viral vectors expression in human neurnnergen-3 gene. DESIGN： Gene directed cloning. SETTING： Central Laboratory of Northern China Coal Medical College. MATERIALS： DH5a competent bacillus coli strain was provided by Capital Medical University; pCDNA3-NT-3 by professor Chen from Bengbu Medical College; pAAV-Laze, pAAV-Helper, pAAV-RC and pAAV-MCS plasmids by Capital Medical University; HEK293 cells by Cell Center of Basic Medical College of Tongji Medical University. METHODS： NT-3 genes which were selected from pCDNA3-NT-3 plasmids were cloned in pAAV-MCS to form a recombinant adeno-associated viral plasmid （pAAV-NT-3）. pAAV-NT-3, pAAV-RC, pAAV-LacZ and pHelper plasmids were extracted, purified and subjected to enzyme-shearing evaluation. In addition, pAAV-NT-3 and pAAV-LacZ were cotransfected with pHelper and pAAV-RC, respectively into AVV-293 cells with DNA mediated by calcium superphosphate transfection gene; and then, AVV-293 cells were packed into recombinant adeno-associated viral rAAV-NT-3 and rAAV-LacZ. After collection of viral particles, rAAV-LacZ viral stock solution was diluted based on ratio of 10：1 and the mixture was used to infect HT 1080 cells. X-gal stain was used to measure virus titer. MAIN OUTCOME MEASURES： Size of targeted gene fragments, validity of vehicle construction and virus titer. RESULTS： Targeted gene NT-3 was successfully inserted into the relative vehicle pAAV and pAAV-NT-3 was correctly recongnized by enzyme-shearing evaluation. Enzyme-shearing electrophoresis demonstrated that pAAV-NT-3, pAAV-RC, pAAV-LacZ and pHelper plasmids were successfully extracted and purified. β-galactoside staining in situ indicated that LacZ genes were expressed in human fibrosarcoma cells （HT1080） and the recombinant virus titer was measured as 1 ×10^12 virus particles per milliliter. CONCLUSION： Total-length cDNA fragment of NT-3 gene, which is obtained from pCDNA3-NT-3 plasmids, is closely matched to polyclone enzyme-shearing sites of adeno-associated viral vectors, while the combination can be used to construct recombinant adeno-associated viral vectors expression in hNT-3 gene.

Phylogenetic analysis of the genomes of two strains of human adenovirus type 3

Human adenovirus type 3 （HAdV-3） is widely prevalent all over the world, especially in Asia. The objective of this study is to carry out complete genomic DNA sequencing and the phylogenetic analysis for two strains （Guangzhou01 and Guangzhou02） of HAdV-3 wild virus isolated from South China. Nasopharyngeal secretion aspirate specimens of sick children were inoculated into HEp-2 and HeLa culture tubes, and the cultures were identified by neutralization assay with type-specific reference rabbit antiserum. Type-specific primers were also utilized to confirm the serotype. The restriction fragments of HAdV genome DNA were cloned into pBlueScript SK （ ＋ ） vectors and sequenced, and the 5＇ and 3＇ ends of the linear HAdV-3 genome were directly sequenced with double purified genomic DNA as templates. General features of the HAdV-3 genome sequences were explored by using several bio-software. Phylogenetic analysis was done with MEGA 3.0 software. The genomic sequences of Guangzhou01 and Guangzhou02 possess the same 4 early regions and 5 late regions and have 39 coding sequences and two RNA coding sequences. Other non-coding regions are conservative. Inverted repeats and palindromes were identified in the genome sequences. The genomes of group B human adenovirus as well as HAdV-3 have close phylogenetic relationship with that of chimpanzee adenovirus type 21. The genomic lengths of these two isolated strains are 35 273 bp and 35 269 bp, respectively. The phylogenetic analysis showed that HAdV-B species has some relationship with certain types of chimpanzee adenovirus.

Analysis of severe human adenovirus infection outbreak in Guangdong Province,southern China in 2019

During 2018–2019,a severe human adenovirus(HAdV)infection outbreak occurred in southern China.Here,we screened 18 respiratory pathogens in 1704 children(≤14 years old)hospitalized with acute respiratory illness in Guangzhou,China,in 2019.In total,151 patients had positive HAdV test results;34.4%(52/151)of them exhibited severe illness.HAdV infection occurred throughout the year,with a peak in summer.The median patient age was 3.0(interquartile range:1.1–5.0)years.Patients with severe HAdV infection exhibited increases in12 clinical indexes(P≤0.019)and decreases in four indexes(P≤0.007),compared with patients exhibiting nonsevere infection.No significant differences were found in age or sex distribution according to HAdV infection severity(P>0.05);however,the distributions of comorbid disease and HAdV co-infection differed according to HAdV infection severity(P<0.05).The main epidemic types were HAdV-3(47.0%,71/151)and HAdV-7(46.4%,70/151).However,the severe illness rate was significantly higher in patients with HAdV-7(51.4%)than in patients with HAdV-3(19.7%)and other types of HAdV(20%)(P<0.001).Sequencing analysis of genomes/capsid genes of 13 HAdV-7 isolates revealed high similarity to previous Chinese isolates.A representative HAdV-7isolate exhibited a similar proliferation curve to the curve described for the epidemic HAdV-3 strain Guangzhou01(accession no.DQ099432)(P>0.05);the HAdV-7 isolate exhibited stronger virulence and infectivity,compared with HAdV-3(P<0.001).Overall,comorbid disease,HAdV co-infection,and high virulence and infectivity of HAdV-7 were critical risk factors for severe HAdV infection;these data can facilitate treatment,control,and prevention of HAdV infection.

Seroprevalence of Neutralizing Antibodies against Six Human Adenovirus Types Indicates the Low Level of Herd Immunity in Young Children from Guangzhou, China

Human adenoviruses(HAdVs) commonly cause many diseases such as respiratory diseases, gastroenteritis, cystitis worldwide. HAdV-3,-7,-4 and emergent HAdV-55 and HAdV-14 are the most important types causing severe respiratory diseases. There is no effective drug available for clinical treatment, and no vaccine available for the general population.Therefore, it is important to investigate the seroprevalence against HAdV for developing novel vaccines and vectors. In this study, we investigated the seroprevalence and titer levels of neutralizing antibodies(NAb) against HAdV-3,-4,-7,-14,-55,and-11 in total 278 healthy populations between 0 months and 49 years of age(228 children and 50 adults) from Guangzhou. In children under the age of 18 years, the seropositive rates were significantly increased against HAdV-3 at12.07%, 33.96%, and 64.29% and against HAdV-7 at 0%, 18.87%, and 19.05% in age groups of 1–2, 3–5, and 6–17 years,respectively. The seroprevalence was very low(0% - 8.1%) for all other four types. In adults aged between 18 and49 years, HAdV-3,-4, and-7(> 50.00%) were the most common types, followed by HAdV-14(38.00%),-55(34.00%),and-11(24.00%). Adults tended to have high NAb titers against HAdV-4 and-55. HAdV-55-seropositive donors tended to be HAdV-11-and HAdV-14-seropositive. These results indicated the low level of herd immunity against all six HAdV types in young children, and HAdV-14,-55,-11 in adults from Guangzhou City. Our findings demonstrate the importance of monitoring HAdV types and developing vaccines against HAdV for children and adults.

Current status of human adenovirus infection in China

Background Outbreaks of severe,acute hepatitis among children have recently attracted global attention.The pathogen causing the outbreak remains unknown,but there is growing evidence that it may be associated with human adenovirus(HAdV).Data sources A review of adenovirus-related clinical studies,epidemiological studies,etiological studies,and case reports was conducted by reviewers independently.Results HAdV can cause a wide variety of clinical symptoms.In the Mainland of China,HAdV infection accounts for 5.8%–13%of patients with acute respiratory infections,and these infections are mainly caused by species B,C,and E of HAdV.For acute conjunctivitis,39.8%–74.9%of sporadic cases were infected by B and D species of HAdV.Outbreaks of keratoconjunctivitis and pharyngoconjunctival fever related to HAdV infection could be found throughout the country.In pediatric patients with acute gastroenteritis,HAdV-41 was the predominant HAdV type,followed by HAdV species B and C.Several types of HAdV,including HAdV-5,HAdV-7,HAdV-1,and HAdV-2,have previously been reported as potential pathogens associated with HAdV hepatitis in immunocompromised patients.However,few HAdV-related hepatitis cases have been reported in China to date.Conclusions There are no systematic surveillance and clinical studies on HAdV hepatitis in China.Therefore,it is imperative to establish a nationwide HAdV virological surveillance system to collect relevant clinical,epidemiological and virological surveillance data and risk factor information as soon as possible to assess the potential risk of HAdV hepatitis among children.

Human adenovirus(HAdV)infection in children with acute respiratory tract infections in Guangzhou,China,2010–2021:a molecular epidemiology study

Background Human adenovirus(HAdV)infection can cause a variety of diseases.It is a major pathogen of pediatric acute respiratory tract infections(ARIs)and can be life-threatening in younger children.We described the epidemiology and subtypes shifting of HAdV among children with ARI in Guangzhou,China.Methods We conducted a retrospective study of 161,079 children diagnosed with acute respiratory illness at the Guangzhou Women and Children’s Medical Center between 2010 and 2021.HAdV specimens were detected by real-time PCR and the hexon gene was used for phylogenetic analysis.Results Before the COVID-19 outbreak in Guangzhou,the annual frequency of adenovirus infection detected during this period ranged from 3.92%to 13.58%,with an epidemic peak every four to fve years.HAdV demonstrated a clear seasonal distribution,with the lowest positivity in March and peaking during summer(July or August)every year.A signifcant increase in HAdV cases was recorded for 2018 and 2019,which coincided with a shift in the dominant HAdV subtype from HAdV-3 to HAdV-7.The latter was associated with a more severe disease compared to HAdV-3.The average mortality proportion for children infected with HAdV from 2016 to 2019 was 0.38%but increased to 20%in severe cases.After COVID-19 emerged,HAdV cases dropped to 2.68%,suggesting that non-pharmaceutical interventions probably reduced the transmission of HAdV in the community.Conclusion Our study provides the foundation for the understanding of the epidemiology of HAdV and its associated risks in children in Southern China.

Application of Human Adenovirus Genotyping by Phylogenetic Analysis in an Outbreak to Identify Nosocomial Infection

Nosocomial infections are common in pediatric patients and can be fatal in infants and immunocompromised patients. In September 2018, a high positive rate of human adenovirus HAdV was occurred among hospitalized children in the Children's Hospital Affiliated to the Capital Institute of Paediatrics in Beijing. To investigate whether this outbreak of HAdV was related to nosocomial infections or the result of community infections, we collected respiratory specimens from patients with acute respiratory infections in a respiratory ward during June to December 2018, and screened for respiratory viruses. Among 1,840 cases included, 95(5.2%, 95/1840) were positive for HAdV and 81 were genotyped based on phylogenetic analysis, including seven as HAdV-1(8.6%), 30 HAdV-3(37.0%), two HAdV-6(2.5%), and 42 HAdV-7(51.9%). More HAdV-positive samples were collected in August(4.7%, 12/255), September(15.0%, 41/274) and October(6.9%, 17/247), with a peak in September 2018. By combining the results of HAdV phylogenetic analysis with clinical data of patients, there were 77 cases(4.2%, 77/1840;81.1%, 77/95) excluded from nosocomial infections, eight cases representing possible infections transmitted by visitors or attending parents, three cases without sequences that might have been due to infection transmitted by roommates positive for HAdV, one case of a roommate without an HAdV sequence, and six cases that shared highly homologous sequences with those of their roommates, for which nosocomial infections might be considered. In conclusion, genotyping of HAdVs based on phylogenetic analysis combined with clinical information provides a powerful method to distinguish nosocomial infections from community acquired infection, especially when tracing the origins of nosocomial infections.

Desmoglein 2(DSG2) Is A Receptor of Human Adenovirus Type 55 Causing Adult Severe Community-Acquired Pneumonia

Human adenovirus type 55(HAdV-B55) is a re-emergent acute respiratory disease pathogen that causes adult communityacquired pneumonia(CAP). Previous studies have shown that the receptor of HAdV-B14, which genome is highly similar with HAdV-B55, is human Desmoglein 2(DSG2). However, whether the receptor of HAdV-B55 is DSG2 is undetermined because there are three amino acid mutations in the fiber gene between HAdV-B14 and HAdV-B55. Here, firstly we found the 3T3 cells, a mouse embryo fibroblast rodent cell line which does not express human DSG2, were able to be infected by HAdV-B55 after transfected with pcDNA3.1-DSG2, while normal 3T3 cells were still unsusceptible to HAdV-B55 infection. Next, A549 cells with h DSG2 knock-down by siRNA were hard to be infected by HAdV-B3/-B14/-B55, while the control siRNA group was still able to be infected by all these types of HAdVs. Finally, immunofluorescence confocal microscopy indicated visually that Cy3-conjugated HAdV-B55 viruses entered A549 cells by binding to DSG2 protein.Therefore, DSG2 is a major receptor of HAdV-B55 causing adult CAP. Our finding is important for better understanding of interactions between adenoviruses and host cells and may shed light on the development of new drugs that can interfere with these processes as well as for the development of potent prophylactic vaccines.

Genetic Analysis of Human Adenovirus Type 7 Strains Circulating in Different Parts of China

To investigate the molecular epidemiology and genetic variation of human adenovirus type 7(HAdV-7)in children with acute respiratory infections(ARI)in China.HAdV-7-positive respiratory samples collected from children with ARI in Beijing,Shijiazhuang,Wenzhou and Guangzhou from 2014–2018 were selected for gene amplification and sequence analysis.Fifty-seven HAdV-7 clinical strains with hexon,penton base and fiber gene sequences were obtained.Meanwhile17 strains were selected randomly from different cities for whole genome sequencing.Phylogenetic and variation analyses were performed based on the obtained sequences,HAdV-7 prototype strain Gomen(AY594255),vaccine strains(AY495969 and AY594256)and representative sequences of strains.The phylogenetic trees constructed based on whole genome sequences,major capsid protein genes(hexon,penton base and fiber)and the early genes(E1,E2,E3 and E4)were not completely consistent.The HAdV-7 strains obtained in this study always clustered with most of the circulating strains worldwide from the 1980 s to the present.Compared with the HAdV-7 prototype strain Gomen(AY594255),some amino acid mutations in loop1 and loop2 of hexon and the RGD loop region of the penton base gene were observed.Recombination analysis showed that partial regions of 55 k Da protein and 100 kDa hexon-assembly associated protein genes among all HAdV-7 strains in this study were from HAdV-16 and HAdV-3,respectively.Our study demonstrated the molecular evolution characteristics of HAdV-7 strains circulating in China and provided basic reference data for the prevention,control and vaccine development of HAdV-7.

Construction and Characterization of a Novel Recombinant Attenuated and Replication-Deficient Candidate Human Adenovirus Type 3 Vaccine:"Adenovirus Vaccine Within an Adenovirus Vector"

Human adenoviruses(HAd Vs)are highly contagious and result in large number of acute respiratory disease(ARD)cases with severe morbidity and mortality.Human adenovirus type 3(HAd V-3)is the most common type that causes ARD outbreaks in Asia,Europe,and the Americas.However,there is currently no vaccine approved for its general use.The hexon protein contains the main neutralizing epitopes,provoking strong and lasting immunogenicity.In this study,a novel recombinant and attenuated adenovirus vaccine candidate against HAd V-3 was constructed based on a commercially-available replication-defective HAd V-5 gene therapy and vaccine vector.The entire HAd V-3 hexon gene was integrated into the E1 region of the vector by homologous recombination using a bacterial system.The resultant recombinants expressing the HAd V-3 hexon protein were rescued in AD293 cells,identified and characterized by RT-PCR,Western blots,indirect immunofluorescence,and electron microscopy.This potential vaccine candidate had a similar replicative efficacy as the wild-type HAd V-3 strain.However,and importantly,the vaccine strain had been rendered replication-defective and was incapable of replication in A549 cells after more than twentygeneration passages in AD293 cells.This represents a significant safety feature.The mice immunized both intranasally and intramuscularly by this vaccine candidate raised significant neutralizing antibodies against HAd V-3.Therefore,this recombinant,attenuated,and safe adenovirus vaccine is a promising HAd V-3 vaccine candidate.The strategy of using a clinically approved and replication-defective HAd V-5 vector provides a novel approach to develop universal adenovirus vaccine candidates against all the other types of adenoviruses causing ARDs and perhaps other adenovirus-associated diseases.

Autophagy induced by human adenovirus B7 structural protein VI inhibits viral replication

Human adenovirus B7(HAdV-B7)causes severe acute lower respiratory tract infections in children.However,neither the child-specific antivirals or vaccines are available,nor the pathogenesis is clear.Autophagy,as part of innate immunity,plays an important role in resistance to viral infection by degrading the virus and promoting the development of innate and adaptive immunity.This study provided evidence that HAdV-B7 infection induced complete autophagic flux,and the pharmacological induction of autophagy decreased HAdV-B7 replication.In this process,the host protein Bcl2-associated athanogene 3(BAG3)mediated autophagy to inhibit the replication of HAdV-B7 by binding to the PPSY structural domain of viral protein pVI through its WW structural domain.These findings further our understanding of the host immune response during viral infection and will help to develop broad anti-HAdV therapies.

Adenovirus F40/41 Gastroenteritis-Associated Emphysematous Gastritis:A Case Report

Emphysematous gastritis(EG)is a rare form of gastritis characterized by gastric wall pneumatosis.It is associated with a high mortality rate.Our case report describes a patient with a history of atrial fibrillation treated with apixaban,prior stroke,and schizoaffective disorder who showed epigastric tenderness on examination.However,no peritonitis signs were recorded,and laboratory values revealed high lactate levels and the presence of adenovirus F40/41.Abdominal computed tomography scan showed extensive portal venous gas in the left hepatic lobe of the liver,as well as pneumatosis involving the entire stomach,indicating EG.The diagnosis was histologically confirmed and initially managed medically,which proved inefficacious,necessitating surgical intervention in the form of a laparotomy and esophagojejunostomy with Roux-en-Y reconstruction.This case report suggests a potential association between EG and adenovirus F40/41–induced gastroenteritis,thereby emphasizing the challenging nature of EG.It underscores the need for comprehensive research to enhance our understanding of its underlying causes and effective treatment strategies.

Effect of adenovirus-mediated gene transfection of vascular endothelial growth factor on survival of random flaps in rats

Objective: To evaluate the effect of local application of vascular endothelial growth factor ( VEGF ) via adenovirus-mediated gene transfer on survival of full thickness flaps selected randomly in rats.Methods: Thirty Sprague-Dawley rats weighing 480-520 g were used in this study. A dorsal flap (8 cm × 2 cm) in full thickness with the pedicle located at the level of the iliac crest was designed. Then the rats received 1 012 pfu replication-deficient recombinant adenovirus carrying VEGF ( AdCMV-VEGF group, n = 10 ), 1012 pfu recombinant β-galactosidase adenovirus ( AdCMV-Gal group, n = 10) and 1 ml saline (saline group, n = 10), respectively, in the distal two thirds of the proposed flap by means of subdermal injection at 8 different locations. Three days after treatment, the flaps were elevated as originally designed and sutured back in situ. The survival rate of the flaps was evaluated on day 7 after operation.Results: The survival rate of the flaps in the AdCMV-VEGF group increased significantly as compared with those of the AdCMV-Gal group (P < 0.01) and the saline group ( P < 0.01). Immunohistochemical staining showed that VEGF was expressed in the survival flaps injected with AdCMV-VEGF. Histological analysis showed that more granulation tissues and angiogenesis were observed in the AdCMV-VEGF group than those in the AdCMV-Gal and the saline groups.Conclusions: Local application of adenovims-mediated VEGF165 cDNA may efficiently improve the survival of ischemic skin flaps.

Clinical epidemiology and disease burden of adenoviral encephalitis in hospitalized children in China:A nationwide cross-sectional study

Importance:Adenovirus encephalitis is a significant infectious disease of the central nervous system that commonly affects children under the age of 5 and has a profound impact on the health of infants and young children throughout China.National multicenter epidemiological studies have significant public health implications.Objective:This study aims to report the epidemiology of adenovirus encephalitis in hospitalized children in China,providing valuable guidance for clinicians.Methods:The data utilized in this study were extracted from the comprehensive Futang Update Medical Records database,which comprises discharge medical records collected by 27 tertiary children’s hospitals between January 2016 and December 2018 in China.Specifically,the face sheet of discharge medical records encompassed critical sociodemographic variables and basic medical care details.Results:In this database,a total of 544 children were hospitalized due to adenoviral encephalitis.The male-to-female ratio was 1.62:1,with more boys being affected across different age groups and places of residence.Of the children hospitalized,the highest number of hospitalizations occurred in the 1–3-year age group and the number of hospitalizations decreased each year from 2016 to 2018.The disease exhibits seasonal characteristics with a pronounced peak in the summer months of June and July.While most children(58%)did not have any significant complications,one-third of them developed respiratory complications,including pneumonia and acute bronchitis.The median length of stay for adenoviral encephalitis was 7 days,and the median cost of hospitalization was 2145.56 US dollars.Interpretation:This study highlights the prevalence of adenovirus encephalitis in hospitalized children in China.Children aged 1–3 years were found to be the main demographic hospitalized due to this condition,with boys being significantly more affected than girls.The seasonal variations of adenovirus encephalitis were also found to be significant.Fortunately,the fatality rate associated with this condition was low,and the prognosis was generally favorable.

Seroprevalence of neutralizing antibodies against adenovirus type 26 and 35 in healthy populations from Guangdong and Shandong provinces,China

Human adenoviruses type 26(HAdV26)and type 35(HAdV35)have increasingly become the choice of adenovirus vectors for vaccine application.However,the population pre-existing immunity to these two adenoviruses in China,which may reduce vaccine efficacy,remains largely unknown.Here,we established micro-neutralizing(MN)assays to investigate the seroprevalence of neutralizing antibodies(nAbs)against HAdV26 and HAdV35 in the general population of Guangdong and Shandong provinces,China.A total of 1184 serum samples were collected,47.0%and 15.8%of which showed HAdV26 and HAdV35 nAb activity,respectively.HAdV26-seropositive individuals tended to have more moderate nAbs titers(201-1000),while HAdV35-seropositive individuals appeared to have more low nAbs titers(72-200).The seropositive rates of HAdV26 and HAdV35 in individuals younger than 20 years old were very low.The seropositive rates of HAdV26 increased with age before 70 years old and decreased thereafter,while HAdV35 seropositive rates did not show similar characteristics.Notably,the seropositive rates and nAb levels of both HAdV26 and HAdV35 were higher in Guangdong Province than in Shandong Province,but did not exert significant differences between males and females.The seroprevalence between HAdV26 and HAdV35 showed little correlation,and no significant cross-neutralizing activity was detected.These results clarified the characteristics of the herd immunity against HAdV26 and HAdV35,and provided information for the rational development and application of HAdV26 and HAdV35 as vaccine vectors in China.