Generation of temperature-sensitive human metapneumovirus strains that provide protective immunity in hamsters

• Published in: Journal of general virology Vol. 89; no. 7; pp. 1553 - 1562
• Main Authors: Herfst, Sander, de Graaf, Miranda, Schrauwen, Eefje J. A, Sprong, Leo, Hussain, Karim, van den Hoogen, Bernadette G, Osterhaus, Albert D. M. E, Fouchier, Ron A. M
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.07.2008; Society for General Microbiology
• Subjects: Animals; Antibodies, Viral - blood; Biological and medical sciences; Chlorocebus aethiops; Cricetinae; Female; Fundamental and applied biological sciences. Psychology; Hot Temperature; Human metapneumovirus; Lung - virology; Metapneumovirus - genetics; Metapneumovirus - growth & development; Metapneumovirus - immunology; Microbiology; Miscellaneous; Mutation; Paramyxoviridae Infections - immunology; Paramyxoviridae Infections - prevention & control; Pneumonia, Viral - prevention & control; Respiratory syncytial virus; Respiratory Syncytial Viruses - genetics; Respiratory System - virology; Respiratory Tract Infections - prevention & control; Respiratory Tract Infections - virology; Vero Cells; Viral Vaccines - genetics; Viral Vaccines - immunology; Virology; Virus Replication - radiation effects; Immunoprotection; Vertebrata; Temperature; Mammalia; Microbiology; Animal; Rodentia; Hamster; Strain; Human metapneumovirus
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/vir.0.2008/002022-0

Department of Virology, Erasmus Medical Center, Rotterdam, The Netherlands Correspondence Ron A. M. Fouchier r.fouchier{at}erasmusmc.nl Human metapneumovirus (HMPV) causes acute respiratory tract illness primarily in young children, immunocompromised individuals and the elderly. Vaccines would be desirable to prevent severe illnesses in these risk groups. Here, we describe the generation and evaluation of cold-passage (cp) temperature-sensitive (ts) HMPV strains as vaccine candidates. Repeated passage of HMPV at low temperatures in Vero cells resulted in the accumulation of mutations in the viral genome. Introduction of these mutations in a recombinant HMPV by reverse genetics resulted in a ts-phenotype, judged on the decreased shut-off temperature for virus replication in vitro . As an alternative approach, three previously described cp-respiratory syncytial virus (cp-HRSV) mutations were introduced in a recombinant HMPV, which also resulted in a low shut-off temperature in vitro . Replication of these ts-viruses containing either the cp-HMPV or cp-HRSV mutations was reduced in the upper respiratory tract (URT) and undetectable in the lower respiratory tract (LRT) of hamsters. Nevertheless, high titres of HMPV-specific antibodies were induced by both ts-viruses. Upon immunization with the ts-viruses, the LRT of hamsters were completely protected against challenge infection with a heterologous HMPV strain, and URT viral titres were reduced by 10 000-fold. In conclusion, we provide proof-of-principle for two candidate live-attenuated HMPV vaccines that induce cross-protective immunity to prevent infection of the LRT in Syrian golden hamsters. Further mapping of the molecular determinants of attenuation of HMPV should be the subject of future studies. Published online ahead of print on 24 April 2008 as DOI 10.1099/vir.0.2008/002022-0.