A Novel Replication-Competent Vaccinia Vector MVTT Is Superior to MVA for Inducing High Levels of Neutralizing Antibody via Mucosal Vaccination

Mucosal vaccination offers great advantage for inducing protective immune response to prevent viral transmission and dissemination. Here, we report our findings of a head-to-head comparison of two viral vectors modified vaccinia Ankara (MVA) and a novel replication-competent modified vaccinia Tian Tan (MVTT) for inducing neutralizing antibodies (Nabs) via intramuscular and mucosal vaccinations in mice. MVTT is an attenuated variant of the wild-type VTT, which was historically used as a smallpox vaccine for millions of Chinese people. The spike glycoprotein (S) of SARS-CoV was used as the test antigen after the S gene was constructed in the identical genomic location of two vectors to generate vaccine candidates MVTT-S and MVA-S. Using identical doses, MVTT-S induced lower levels (∼2-3-fold) of anti- SARS-CoV neutralizing antibodies (Nabs) than MVA-S through intramuscular inoculation. MVTT-S, however, was capable of inducing consistently 20-to-100-fold higher levels of Nabs than MVA-S when inoculated via either intranasal or intraoral routes. These levels of MVTT-S-induced Nab responses were substantially (∼10-fold) higher than that induced via the intramuscular route in the same experiments. Moreover, pre-exposure to the wild-type VTT via intranasal or intraoral route impaired the Nab response via the same routes of MVTT-S vaccination probably due to the pre-existing anti-VTT Nab response. The efficacy of intranasal or intraoral vaccination, however, was still 20-to-50-fold better than intramuscular inoculation despite the subcutaneous pre-exposure to wild-type VTT. Our data have implications for people who maintain low levels of anti-VTT Nabs after historical smallpox vaccination. MVTT is therefore an attractive live viral vector for mucosal vaccination

Serological and molecular screening for viruses in blood donors from Ntcheu, Malawi: High prevalence of HIV-1 subtype C and of markers of hepatitis B and C viruses

The prevalence of antibodies to human immunodeficiency virus type 1 (HIV-1), hepatitis C virus (HCV), human T lymphotropic virus I (HTLV-1), and hepatitis B (HBV) surface antigen (HBsAg) was determined in blood donors from Ntcheu, Malawi. Each donation was also screened for HIV-1 RNA and HCV RNA. Among 159 blood donations, the prevalence of HIV-1 infection was 10.7%, 8.1% for HBV carriage, 6.8% for anti-HCV, and 2.5% for anti-HTLV-1. HIV-1/HTLV-1 and HIV-1/ HCV dual infections were observed in 1.2% of the donations. Consequently, 13% of blood donors from Ntcheu should be deferred for retroviral infections and 15% for hepatitis viral infections. Sequence analyses of the HIV-1 strains revealed a relatively homogeneous circulation of subtype C viruses in Malawi. These findings confirm the high endemicity of blood-borne viruses in Malawi and the need for a sensitive viral screening of blood donations to improve blood safety. © 2001 Wiley-Liss, Inc.link_to_subscribed_fulltex

Comparative analysis of the expression of the Epstein-Barr virus (EBV) anti-apoptotic gene BHRF1 in nasopharyngeal carcinoma and EBV-related lymphoid diseases

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