Recombinant human parainfluenza virus type 2 vaccine candidates containing a 3' genomic promoter mutation and L polymerase mutations are attenuated and protective in non-human primates.
Previously, we identified several attenuating mutations in the L polymerase protein of human parainfluenza virus type 2 (HPIV2) and genetically stabilized those mutations using reverse genetics [Nolan SM, Surman S, Amaro-Carambot E, Collins PL, Murphy BR, Skiadopoulos MH. Live-attenuated intranasal parainfluenza virus type 2 vaccine candidates developed by reverse genetics containing L polymerase protein mutations imported from heterologous paramyxoviruses. Vaccine 2005;39(23):4765-74]. Here we describe the discovery of an attenuating mutation at nucleotide 15 (15(T-->C)) in the 3' genomic promoter that was also present in the previously characterized mutants. We evaluated the properties of this promoter mutation alone and in various combinations with the L polymerase mutations. Amino acid substitutions at L protein positions 460 (460A or 460P) or 948 (948L), or deletion of amino acids 1724 and 1725 (Delta1724), each conferred a temperature sensitivity (ts) phenotype whereas the 15(T-->C) mutation did not. The 460A and 948L mutations each contributed to restricted replication in the lower respiratory tract of African green monkeys, but the Delta1724 mutation increased attenuation only in certain combinations with other mutations. We constructed two highly attenuated viruses, rV94(15C)/460A/948L and rV94(15C)/948L/Delta1724, that were immunogenic and protective against challenge with wild-type HPIV2 in African green monkeys and, therefore, appear to be suitable for evaluation in humans.
Laboratory of Infectious Diseases, Respiratory Viruses Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Sheila M
SM
Nolan
Mario H
MH
Skiadopoulos
Konrad
K
Bradley
Olivia S
OS
Kim
Stacia
S
Bier
Emerito
E
Amaro-Carambot
Sonja R
SR
Surman
Stephanie
S
Davis
Marisa
M
St Claire
Randy
R
Elkins
Peter L
PL
Collins
Brian R
BR
Murphy
Anne
A
Schaap-Nutt
D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D006801:Humans; D008253:Macaca mulatta; D008647:Mesocricetus; D009154:Mutation; D022241:Parainfluenza Vaccines / Q000276:immunology*; D010223:Parainfluenza Virus 2, Human / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D011401:Promoter Regions, Genetic; D012137:Respiratory System / Q000821:virology; D013696:Temperature; D014613:Vaccines, Attenuated / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology*; D014764:Viral Proteins / Q000235:genetics*; D014779:Virus Replication
D022241:Parainfluenza Vaccines; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D014764:Viral Proteins; C069129:L protein, Human parainfluenza virus 2