Immunogenicity of recombinant human bocavirus-1,2 VP2 gene virus-like particles in mice.

Human bocavirus (HBoV), a recently identified pathogen with a worldwide distribution is closely related to paediatric acute respiratory infection and gastroenteritis. The present study was performed to evaluate the immunogenicity of HBoV1 and HBoV2 virus-like particles (VLPs) as vaccine candidates in mice. Both HBoV1 and HBoV2 VLPs were expressed in the bacmid virus­SF9 cell system. Mice were inoculated three times at 3-week intervals with HBoV VLPs at one dose intramuscular (i.m.) or intradermal (i.d.) with or without the addition of the alum adjuvant. ELISA was used to detected antibody, and ELISPOT was used to test cellular immune responses. HBoV-specific IgG antibodies were induced and alum adjuvant improved the antibody titres and avidity, while the inoculation pathway had no influence. T helper type 1/ type 2 immune responses were balanced induced by HBoV1 VLPs but not HBoV2 VLPs. Serum IgG antibody cross-reactivity rates of the two subtypes were similar, but cross-reactions of HBoV1 immunization groups were higher. The single i.m. group had more interferon-γ-secreting splenocytes. These data indicate that HBoV VP2 VLPs have good immunogenicity with induction of strong humoral and cellular immune responses, and they may be potential candidate vaccines for HBoV infection.

Identification of human bocaviruses in the cerebrospinal fluid of children hospitalized with encephalitis in China.

BACKGROUND: Encephalitis is a major cause of death and disability in adults and children; different members in the family Parvoviridae are known to be associated with encephalitis to some extent. OBJECTIVES: To determine the presence of human bocaviruses (HBoVs) and corresponding HBoV-specific immunoglobulins (Igs) in cerebrospinal fluid from children with suspected viral encephalitis. STUDY DESIGN: Employing real-time PCR and nested touchdown PCR, 67 cerebrospinal fluid (CSF) samples from children with suspected viral encephalitis were screened for HBoV and routine encephalitis-causing viruses. Using ELISA, Western blot and IFA, HBoV-specific Ig were determined in the samples. RESULTS: Nine samples (134%) were HBoV1 DNA-positive, while one sample (15%) was HBoV2 DNA-positive. HBoV-specific IgM and IgG antibodies were detected in the CSF samples from three children; two samples were HBoV1 DNA-positive and one sample was negative. One death was recorded; CSF from this child was the only HBoV-IgM-positive CSF samples among the 67 CSF tested. CONCLUSION: We screened CSF samples obtained from children with encephalitis for the presence of HBoV1 and HBoV2 and specific IgM- or IgG-responses. Detection of viral DNA and/or immunological response to HBoV1/HBoV2 highlights the significance of these viruses as causes of encephalitis in children. Further studies are needed to examine the role of HBoV infection in children encephalitis.

[Optimizing expression of the capsid protein VP2 from human Bocavirus and establish it's seroepidemiology assying methord].

OBJECTIVE: To obtain sufficient recombinant VP2 protein of human Bocavirus and establish it's seroepidemiology assying metbord. METHORD: Tbe capsid protein VP2 DNA genes of HBoV1 and 2 were optimized in accordance with tbe usage of the favorite codons in K coil so as to enhance its protein expression in prokaryotic expressing system. The protein was purified by Ni-NTA column, and its antigenicity was determined by Western Blot. Then establish ELISA to detect the specific anti-VP2 IgG antibodies against HBoV1 and 2 in healthy children aged 3-6 years in Nanjing, China. RESULTS: The recombinant protein 6 x His-VP2 was produced in a larger quantity at 25 degrees C induced by IPTG (1 mmol/L) over night and purified by Ni-NTA column. Seropositive rates of HBoV1 and 2 were 62.2% and 55.5% and their mixed seropositivity was 37%. CONCLUSION: The optimizing expression of the capsid protein VP2 from human Bocavirus constructed successfully and get a high yield under certain conditions. The established ELISA could be used to further analyze seroepidemiology of HBoV in China.

[Molecular and epidemiological study on viral diarrhea among infants in Lanzhou].

OBJECTIVE: To study the epidemiologic characteristics of viral diarrhea in children under 5 years old in Lanzhou, understand the four major virus in children of distribution. METHODS: In the first hospital of Lanzhou university from Jul 2009 to Jun 2010,we collected 290 stool specimens from children with diarrhea and 114 asymptomatic controls. Rotavirus was detected by ELISA,further strain characterization was carried out by nested PCR. The human calicivirus, astrovirus, adenovirus were detected by RT-multiplex PCR and PCR. RESULTS: At least one of the four viral agents was found in 60% of the specimens. Rotavirus, human calicivirus, adenovirus, and astrovirus were identified in 39.31%, 11.38%, 10.69%, and 4.83% in 290 specimens respectively. Rotavirus G3 was the most prevailing serotype, P [8] was the most common genotype. In the 114 control samples, 7 sample was positived for calicivirus, 5 samples were positived for human adenovirus and 1 sample was positived for astrovirus. CONCLUSION: The results indicated clearly the impact of viral agents causing diarrhea and the importance of long-term systematic surveillance.