Recombinant porcine IFN-gamma potentiates the secondary IgG and IgA responses to an inactivated suid herpesvirus-1 vaccine and reduces postchallenge weight loss and fever in pigs.
The effect of recombinant porcine interferon-gamma (IFN-gamma) on the immunogenicity in vivo of inactivated suid herpesvirus-1 (SHV-1, Phylaxia strain) was studied applying two successive i.m. immunizations. The animals were injected with inactivated virus alone or inactivated virus supplemented with 10(4) or 10(6) U IFN-gamma. After the first immunization, none of the animals responded with measurable virus-neutralizing antibody (VNAb), virus-specific IgG or IgA. Following a second immunization 4 weeks later, a significantly increased VNAb response was noted in animals that had received vaccine doses containing 10(4) U IFN-gamma (p < 0.05). These animals also had significantly augmented serum levels of IgG (p < 0.01) and IgA (p < 0.05). Inclusion of 10(6) U IFN-gamma in the vaccine preparation did not affect the antibody response. In one experiment, the pigs were challenged oronasally with 10(5) TCID50 of the 75V19 strain of SHV-1, 7 weeks after administration of the second vaccine dose. Those that had received 10(4) U IFN-gamma in the vaccination developed less fever during the postchallenge period (p < 0.004). In all challenged pigs, growth performance was compromised during the first week after challenge. However, the only animals retaining an average net increase in body mass were those covaccinated with 10(4) U IFN-gamma (p < 0.05). Nasal excretion of virus was not significantly different between groups that had been vaccinated with or without IFN-gamma. Multiple linear regression analysis of variables from individual vaccinated animals revealed the VNAb response to be correlated with serum IgG levels (p < 0.025) and with postchallenge growth performance (p < 0.0001) but not with serum IgA levels (p > 0.5). On the other hand, serum IgA appeared to be inversely correlated with early nasal virus excretion after challenge (p < 0.006). Taken together, our data suggest that addition of IFN-gamma to inactivated SHV-1 vaccine may be a useful tool for enhancement of both mucosal and systemic immune responses in pigs.
Laboratory of Immunobiology, Rega Institute, University of Leuven, Belgium. koen.vandenbroeck@rega.kuleuven.ac.be
K
K
Vandenbroeck
H
H
Nauwynck
A
A
Vanderpooten
K
K
Van Reeth
B
B
Goddeeris
A
A
Billiau
D000818:Animals; D005334:Fever / Q000188:drug therapy / Q000276:immunology; D011558:Herpesvirus 1, Suid / Q000276:immunology*; D007115:Immunization Schedule; D007070:Immunoglobulin A / Q000096:biosynthesis*; D007074:Immunoglobulin G / Q000096:biosynthesis*; D007273:Injections, Intramuscular; D007371:Interferon-gamma / Q000627:therapeutic use*; D016014:Linear Models; D011994:Recombinant Proteins; D013552:Swine; D015164:Vaccines, Inactivated / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*; D015431:Weight Loss / Q000187:drug effects / Q000276:immunology
D007070:Immunoglobulin A; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D015164:Vaccines, Inactivated; D014765:Viral Vaccines; D007371:Interferon-gamma