Field trial to evaluate immunogenicity of a glycoprotein I (gE)-deleted pseudorabies virus vaccine after its administration in the presence of maternal antibodies.
A field trial was conducted on a commercial swine farm quarantined because of infection with pseudorabies virus. The purpose was to investigate, in growing pigs born to hyperimmunized sows, the immunogenicity of a vaccine with a glycoprotein I (gE) deletion. One hundred twenty pigs were assigned at random to 1 of 3 vaccination schedules at ages: 8 and 12 weeks; 8, 12, and 14 weeks; and 8, 12, and 16 weeks. Immune response was measured at 8, 12, 14, 16, and 18 weeks, using the serum neutralization test, a screening ELISA, and assays of IgG and IgA in serum and nasal secretions. Results of the serum neutralization test and the screening ELISA indicated that, for pigs vaccinated only at 8 and 12 weeks, the percentage of pigs with pseudorabies virus serum antibodies decreased substantially by 18 weeks; for pigs given a booster at 14 or 16 weeks, the prevalence of serum antibodies at 18 weeks was higher, with 16-week booster vaccination eliciting the best response. At each age, nasal IgA and IgG values were highly correlated (r > or = 0.70), as were serum IgA and IgG values; correlations of serum with nasal IgA and IgG values were somewhat lower (approx range, r = 0.40 to 0.70). Nevertheless, an increase in serum IgA or IgG values on vaccination was no guarantee of an increase in nasal IgA or IgG values. For serum and nasal mucosal antibodies, a poor immune response was associated with high quantities of maternally derived antibodies. Vaccination at 16 weeks was necessary to ensure eliciting of an immune response in almost all pigs.
D000375:Aging; D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis* / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D017353:Gene Deletion; D011558:Herpesvirus 1, Suid / Q000276:immunology*; D007115:Immunization Schedule; D007117:Immunization, Secondary; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D011247:Pregnancy; D011557:Pseudorabies / Q000517:prevention & control*; D012044:Regression Analysis; D013552:Swine; D014759:Viral Envelope Proteins / Q000235:genetics*; D014765:Viral Vaccines
D000914:Antibodies, Viral; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C042966:pseudorabies virus glycoproteins