Deletion of gene A41L enhances vaccinia virus immunogenicity and vaccine efficacy

• Published in: Journal of general virology 2006-01, Vol.87 (1), p.29-38
• Main Authors: Clark, Richard H, Kenyon, Julia C, Bartlett, Nathan W, Tscharke, David C, Smith, Geoffrey L
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; CD8-Positive T-Lymphocytes - immunology; Fundamental and applied biological sciences. Psychology; Gene Deletion; Mice; Microbiology; Miscellaneous; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; Vaccinia virus; Vaccinia virus - genetics; Vaccinia virus - immunology; Viral Proteins - isolation & purification; Viral Proteins - physiology; Viral Vaccines - genetics; Viral Vaccines - immunology; Virology
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/vir.0.81417-0

1 Department of Virology, Faculty of Medicine, Imperial College London, Norfolk Place, London W2 1PG, UK 2 Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0440, USA 3 EBV Biology Laboratory, Division of Immunology and Infectious Diseases, Queensland Institute of Medical Research, Herston, QLD 4006, Australia Correspondence Geoffrey L. Smith glsmith{at}imperial.ac.uk Vaccinia virus (VACV) is the vaccine that was used to eradicate smallpox and is being developed as a recombinant vaccine for other pathogens. Removal of genes encoding immunomodulatory proteins expressed by VACV may enhance virus immunogenicity and improve its potential as a vaccine. Protein A41 is a candidate for removal, having sequence similarity to the VACV chemokine-binding protein, vCKBP, and an association with reduced inflammation during dermal infection. Here, it is shown that, at low doses, VACV strain Western Reserve (WR) lacking A41L (v A41L) was slightly more virulent than wild-type and revertant controls after intranasal infection of BALB/c mice. The primary immune response to v A41L was marked by an increase in the percentage of VACV-specific gamma interferon-producing CD8 + T cells and enhancement of cytotoxic T-cell responses in the spleen. However, this augmentation of cellular response was not seen in lung infiltrates. Splenic CD8 + T-cell responses were also enhanced when VACV strain modified vaccinia virus Ankara (MVA) lacking A41L was used to immunize mice. Lastly, immunization with VACV MVA lacking A41L provided better protection than control viruses to subsequent challenge with a 300 LD 50 dose of VACV WR. This study provides insight into the immunomodulatory role of A41 and suggests that MVA lacking A41 may represent a more efficacious vaccine. These authors contributed equally to this work.