Immunoglobulins in the serum and nasal secretions of lambs following vaccination and aerosol challenge with parainfluenza 3 virus.

Serial changes in the concentrations of IgM, IgG and IgA were compared in specific pathogen free (SPF) lambs which had been vaccinated with live or inactivated parainfluenza 3 virus (PI 3) by either intramuscular (IM) or intranasal (IN) routes followed by aerosol challenge with PI 3. In the serum, an increase in IgM was associated with the primary antibody response to the aerosol challenge, whereas increased IgG was associated with the secondary antibody response. No changes in immunoglobulin concentrations were observed in the nasal secretions of lambs administered live or inactivated virus IM or IN without adjuvant. Marked increases in IgG were found in the serum and nasal secretions of lambs vaccinated IM with inactivated virus in Freund's complete adjuvant (FCA) and fractionation by gel filtration confirmed that the antibody was associated with IgG in both these fluids.