The effect of interferon-gamma on genetic immunization.

The effect of co-inoculation of a plasmid vector expressing the rabies virus glycoprotein and an additional vector encoding mouse interferon (IFN)-gamma on the development of an antigen specific B and T helper cell response was tested upon intramuscular inoculation of mice. The effect of IFN-gamma was dependent on the promoter driving expression of the viral antigen. The immune responses to antigen-expressing vector carrying a viral promoter such as the SV40 early promoter or the major histocompatibility (MHC) class I promoter were reduced in presence of IFN-gamma while the B and T helper cell response to a vector expressing the antigen under the control of the MHC class II promoter was not affected by this cytokine.