We have constructed cDNA libraries of human parainfluenza type 1 (PI1) and type 2 (PI2) viral mRNAs in a plasmid vector. Two glycoprotein gene clones from the cDNA libraries, HN of PI1 and F of PI2 virus have already been characterized. Screening continues for the other glycoprotein genes. The HN gene of PI2 has also been synthesized by polymerase chain reaction. In Phase II, these clones will be used to express recombinant glycoproteins in a baculovirus system; the genes will also be modified to produce secreted forms of the glycoproteins. Chimeric glycoprotein genes containing the majority of the extracellular domains of F and HN will also be constructed to produce chimeric secreted glycoproteins. The glycoproteins will be purified by immunoaffinity or lectin affinity chromatography and used for immunization of hamsters. Protection will be determined by analysis of systemic/local antibody responses and by challenge infection. The long ter objective is to produce a multivalent subunit vaccine to control human parainfluenza virus infection.
