Bovine Parainfluenza Virus Type 3 (BPIV3) Fusion and Hemagglutinin-Neuraminidase Glycoproteins Make an Important Contribution to the Restricted Replication of BPIV3 in Primates

Abstract

This study examines the contribution of the fusion (F) and hemagglutinin-neuraminidase (HN) glycoprotein genes of bovine parainfluenza virus type 3 (BPIV3) to its restricted replication in the respiratory tract of nonhuman primates. A chimeric recombinant human parainfluenza type 3 virus (HPIV3) containing BPIV3 F and HN glycoprotein genes in place of its own and the reciprocal recombinant consisting of BPIV3 bearing the HPIV3 F and HN genes (rBPIV3-F H HN H ) were generated to assess the effect of glycoprotein substitution on replication of HPIV3 and BPIV3 in the upper and lower respiratory tract of rhesus monkeys. The chimeric viruses were readily recovered and replicated in simian LLC-MK2 cells to a level comparable to that of their parental viruses, suggesting that the heterologous glycoproteins were compatible with the PIV3 internal proteins. HPIV3 bearing the BPIV3 F and HN genes was restricted in replication in rhesus monkeys to a level similar to that of its BPIV3 parent virus, indicating that the glycoprotein genes of BPIV3 are major determinants of its host range restriction of replication in rhesus monkeys. rBPIV3-F H HN H replicated in rhesus monkeys to a level intermediate between that of HPIV3 and BPIV3. This observation indicates that the F and HN genes make a significant contribution to the overall attenuation of BPIV3 for rhesus monkeys. Furthermore, it shows that BPIV3 sequences outside the F and HN region also contribute to the attenuation phenotype in primates, a finding consistent with the previous demonstration that the nucleoprotein coding sequence of BPIV3 is a determinant of its attenuation for primates. Despite its restricted replication in the respiratory tract of rhesus monkeys, rBPIV3-F H HN H conferred a level of protection against challenge with HPIV3 that was indistinguishable from that induced by previous infection with wild-type HPIV3. The usefulness of rBPIV3-F H HN H as a vaccine candidate against HPIV3 and as a vector for other viral antigens is discussed.Bovine parainfluenza virus type 3 (BPIV3) is restricted in replication in the respiratory tract of rhesus monkeys, chimpanzees, and humans, and it is being evaluated as a vaccine against human PIV3 (HPIV3) (8,10,12,26,27). HPIV3 and BPIV3 are closely related enveloped, nonsegmented, negativestrand RNA viruses within the Respirovirus genus of the Paramyxoviridae family (2, 10). The two viruses are 25% related antigenically by cross-neutralization studies (8), and they share neutralization epitopes on their fusion (F) and hemagglutininneuraminidase (HN) surface glycoproteins (9, 30). HPIV3 and BPIV3 are essentially identical in genome organization (2). Both viruses encode nine proteins: the nucleoprotein (N), phosphoprotein (P), and large polymerase protein (L) are nucleocapsid-associated proteins; the C, D, and V accessory proteins are proteins of unknown function encoded by the P mRNA or by an edited version thereof; the M protein is an internal matrix protein; and the F and HN glycoproteins are protective antigens of the vi...

Contributions of the structural proteins of severe acute respiratory syndrome coronavirus to protective immunity

“…BHPIV3, a recombinant virus containing the surface proteins of HPIV3 and the internal proteins of BPIV3 (7,15), was used as a vector to express the S, M, E, and N structural proteins of SARS-CoV individually or in the combination SME or ME (Fig. 1).…”

“…Titration of SARS-CoV was performed by determination of the tissue culture 50% infectious dose (TCID 50 ) in Vero cells (9). The recombinant BHPIV3 viruses were propagated on simian LLC-MK2 cells at 32°C and titrated by determination of TCID 50 on LLC-MK2 cells (7). designed to have a MluI site downstream of the ORF, whereas the M, E, and N cDNAs each had a MluI site upstream of the gene-end signal and a BssHII site downstream of the ORF.…”

“…BPIV3 is attenuated in primates because of a natural host range restriction and is a promising candidate vaccine against HPIV3 because it is attenuated and immunogenic in infants and young children (8). BHPIV3 is an improved version as it bears major protective antigens that exactly match those of HPIV3 (7). BHPIV3 vectors expressing up to three SARS-CoV structural proteins were evaluated for immunogenicity and protective efficacy in hamsters, which support a high level of pulmonary replication of both SARS-CoV and BHPIV3.…”

New Generation Live Vaccines against Human Respiratory Syncytial Virus Designed by Reverse Genetics

“…B/HPIV3 consists of the attenuated BPIV3 backbone, in which the fusion F and hemagglutinin-neuraminidase HN protective antigen genes have been replaced with their counterparts from HPIV3 ( Figure 4E) (32). The magnitude of expression of the vectored RSV genes in vitro was greater than that of RSV, especially for the single-gene inserts.…”

“…A similar strategy has been successful for HPIV3, which has a bovine counterpart, bovine parainfluenza virus (BPIV) type 3 that is attenuated in primates. Combining the HPIV3 antigenic determinants with backbones containing one or more BPIV3 genes has generated several attenuated derivatives suitable for clinical evaluation (31,32).…”