Development of a novel subunit vaccine that protects cotton rats against both human respiratory syncytial virus and human parainfluenza virus type 3.

A cotton rat model of experimental human respiratory syncytial virus (RSV) and human parainfluenza virus type 3 (PIV-3) infection was used to examine the efficacy of FRHNP, a novel chimeric glycoprotein which contains the extracellular regions of the fusion glycoprotein of RSV and the attachment glycoprotein of PIV-3, as a single subunit vaccine against these two viruses. This work was prompted by previous cotton rat studies that demonstrated that the major protective antigens of the two viruses were these glycoproteins. FRHNP was expressed in insect cells using a recombinant baculovirus. Vaccination with FRHNP resulted in induction of both RSV and PIV-3 neutralizing antibody and doses of 200 ng completely protected rats from either RSV or PIV-3 challenge. These results demonstrate that in the cotton rat animal model a single chimeric glycoprotein can be an effective vaccine against both RSV and PIV-3.