Formulation with CpG ODN enhances antibody responses to an equine influenza virus vaccine.
Previous studies have shown that protection against equine influenza virus (EIV) is partially mediated by virus-specific IgGa and IgGb. In this study we tested whether addition of a CpG ODN formulation to a commercial killed virus vaccine would enhance EIV-specific IgGa and IgGb antibody responses, and improve protection against an experimental EIV challenge. Thirty naïve horses were assigned to one of three groups and vaccinated as follows: 10 were given vaccine (Encevac TC4, Intervet Inc.) alone, 10 were given vaccine plus 0.25 mg CpG ODN 2007 formulated with 30% Emulsigen (CpG/Em), and 10 controls were given saline. All horses were challenged with live virus 12 weeks after the final vaccination. Antibody responses were tested by single radial hemolysis (SRH) and ELISA, and protection was evaluated by determination of temperature, coughing, and clinical scores. Killed virus vaccine combined with CpG/Em induced significantly greater serologic responses than did the vaccine alone. All antibody isotypes tested increased after the addition of CpG/Em, although no shift in relative antibody isotypes concentrations was detected. Vaccination significantly improved protection against challenge but the differences between the two vaccine groups were not statistically significant. This study is the first demonstration that CpG/Em enhances antigen-specific antibody responses in horses and supports its potential to be used as an adjuvant for vaccines against equine infections.
Lopez
A M
AM
Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Sask., S7N 5E3 Canada. marianela.lopez@usak.ca
Hecker
R
R
Mutwiri
G
G
van Drunen Littel-van den Hurk
S
S
Babiuk
L A
LA
Townsend
H G G
HG
D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001831:Body Temperature / Q000276:immunology; D003371:Cough / Q000662:veterinary; D018899:CpG Islands / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D006461:Hemolysis / Q000276:immunology; D006734:Horse Diseases / Q000276:immunology / Q000517:prevention & control / Q000821:virology*; D006736:Horses; D007132:Immunoglobulin Isotypes / Q000097:blood; D053123:Influenza A Virus, H3N8 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology* / Q000627:therapeutic use; D009838:Oligodeoxyribonucleotides / Q000276:immunology*; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary* / Q000821:virology; D014611:Vaccination / Q000379:methods / Q000662:veterinary*; D015164:Vaccines, Inactivated / Q000276:immunology / Q000627:therapeutic use
D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007132:Immunoglobulin Isotypes; D007252:Influenza Vaccines; D009838:Oligodeoxyribonucleotides; D015164:Vaccines, Inactivated