ABSTRACT
This study aims to construct inactivated coxsackievirus A16 (CVA16) vaccine and to investigate its protective effect in ICR mice. A clinical isolate of CVA16, 521-01T, was cultured in VERO cells, inactivated by formaldehyde, and purified by ultracentrifugation for vaccine preparation. Purity and other characteristics of the vaccine were determined by SDS-PAGE and Western blot. Female ICR mice were subcutaneously inoculated with inactivated CVA16 or Al(OH)3-absorbed CVA16, followed by booster immunization at the end of 2 and 4 weeks. CVA16-specific IgG titers in serum were determined by ELISA, and titers of neutralizing antibodies were determined by viral neutralization assay. The immunity of T lymphocytes was evaluated by IFN-gamma ELISPOT assay. The protective effect was evaluated by challenging the neonatal offspring (< 48 hours) of vaccinated female mice with 1 000 LD50 of CVA16 521-01T. The mortality rates of different groups were compared. The results showed that Al(OH)3 +CVA16 could induce high titers of specific IgG antibodies in ICR mice. After being boosted two times, the serum IgG antibody titer could reach up to 1 : 1 x 10(5) (P = 0.000), and neutralizing antibody titer was higher than 1 : 256. Additionally, more spot forming cells were induced in the immunized groups than in the negative controls. The maternal antibodies showed protective effect in 100% of the neonatal mice challenged with 1 000 LD50 of CVA16 521-01T. The inactivated CVA16 vaccine has ideal immunogenicity and immunoprotective effect. This research lays a foundation for the development and evaluation of CVA16 vaccines.
Subject(s)
Animals , Female , Humans , Mice , Antibodies, Neutralizing , Allergy and Immunology , Antibodies, Viral , Allergy and Immunology , Enterovirus , Allergy and Immunology , Enterovirus Infections , Allergy and Immunology , Virology , Immunization , Mice, Inbred ICR , T-Lymphocytes , Allergy and Immunology , Virology , Vaccines, Inactivated , Allergy and Immunology , Viral Vaccines , Allergy and ImmunologyABSTRACT
Epidemics of hand, foot and mouth disease (HFMD) have mainly been caused by Coxsackievirus A16 (CVA16) and Enterovirus A 71 (EV-A71), which circulated alternatively or together in the affected area. CVA16 has caused numerous outbreaks and epidemics in multiple countries and geographical regions, and has become an important public health problem. Based on an analysis of the complete VP1 coding region, all CVA16 strains can be divided into genotypes A, B1, and B2. Furthermore, genotype B1 can be divided into subgenotypes B1a, B1b, and B1c. After 2000, no reports of genotype B2 virus strains have been reported. All of the CVA16 strains reported in mainland China have belonged to subgenotypes B1a and B1b. Most CVA16-associated infections cause only mild symptoms; however, some CVA16 infections can lead to severe complications and even death. Vaccination is considered to be the most effective method to control the transmission and infection rate of this virus. A number of research groups are studying various vaccine types, including inactivated vaccines, genetic engineering vaccines, and DNA vaccines, amongst others. In this review, an overview is provided of the research advances in molecular epidemiology and vaccines of CVA16.
Subject(s)
Animals , Humans , China , Coxsackievirus Infections , Epidemiology , Allergy and Immunology , Virology , Enterovirus A, Human , Classification , Genetics , Molecular Epidemiology , Viral Vaccines , Genetics , Allergy and ImmunologyABSTRACT
To study the epidemic characteristics of human rhinovirus (HRV) in children with acute respiratory infections in Gansu Province. 286 throat swabs were collected from children with acute respiratory in fections in Gansu Province during 2011. Multiplex reverse transcription-PCR (multiplex RT-PCR) assay was used to screen those specimens for detection of common respiratory tract pathogens. For HRV-positive samples, nested reverse transcription polymerase chain reaction (nested RT-PCR) was performed to amplify VP1 and VP4/VP2 gene fragments of HRV. The VP4/VP2 and VP1 regions of HRV-positive samples were sequenced and performed genotype analysis. Of 286 specimens fested, 27 were positive for HRV by multiplex RT-PCR and nested RT-PCR, of which 16 children were made (16/185), 8.64%) and 11 female (11/101,10.89%). The positive rate was 9.44% (27/286). The mean age of HRV-positive children was 3 years in this study, children less than one year old had the highest proportion 44.4% (12/ 27, 44.4%). The highest HRV positive rate fell on May, 2011 (6/27, 22.2%). Common cold accounted for the highest proportion, 12.24% (12/98) followed by pneumonia, 8.50% (13/153). The remaining 2 cases were bronchitis. Sequence analysis showed HRV A was the predominant genotype in Gansu Province in 2011, accounting for 84.62% (22/26) of positive cases, followed by HRV C (11.54%, 3/26) and only one HRV B was detected (3.85%, 1/26). HRV could be detected throughout the year in Gansu Province and primarily infected children under one year old. The group A was the epidemic genotype of HRV and move than one genotype existed in Gansu Province during 2011.