The prevalence of neutralising antibodies to chimpanzee adenovirus type 6 and type 7 in healthy adult volunteers, patients with chronic hepatitis B and patients with primary hepatocellular carcinoma in China

Abstract

The presence of neutralising antibodies (NAbs) against adenovirus in the population is a major hurdle preventing the effective use of replication-defective adenoviruses (Ads) as candidates for gene therapy and vaccine vectors for many diseases. Only a few studies have described the epidemiology of pre-existing immunity to chimpanzee Ads in China. To assess the prevalence of NAbs to chimpanzee adenovirus serotypes 6 and 7 (AdC6 and AdC7), we enrolled 998 healthy participants from five regions in China as well as 196 chronic hepatitis B virus (HBV) patients and 193 primary hepatocellular carcinoma (HCC) patients from Chongqing, China. The total seroprevalence rates of AdC6 and AdC7 NAbs in the healthy participants were 12.22% (122/998) (95% confidence interval [CI], 10.34-14.40%) and 13.13% (131/998) (95% CI, 11.17-15.36%), respectively. The seroprevalence rates of AdC6 and AdC7 NAbs in the HBV patients were 21.43% (42/196) (95% CI, 16.26-27.69%) and 25.51% (50/196) (95% CI, 19.92-32.04%), respectively. The seroprevalence rates of AdC6 and AdC7 NAbs in the HCC patients were 27.46% (53/193) (95% CI, 21.65-34.15%) and 31.09% (60/193) (95% CI, 24.98-37.93%), respectively. The seroprevalence rates of these Ads were not associated with age and gender. The present study may provide useful insights for developing future AdC-based vaccines and gene therapies.