Recombinant respiratory syncytial virus lacking secreted glycoprotein G is attenuated, non-pathogenic but induces protective immunity.
Respiratory syncytial virus (RSV) causes intense pulmonary inflammatory responses in some infected infants. The surface attachment protein 'G' of RSV has membrane-bound and secreted forms and shows homology to the CX3C chemokine fractalkine. Using recombinant techniques, we generated replication-competent recombinant clonal RSV expressing normal G proteins ('rRSV') or only the membrane-bound form of G ('Gmem rRSV'). Both recombinants grew well in HEp-2 cells, but after primary intranasal infection in mice, pulmonary Gmem rRSV replication was reduced tenfold compared to parental or rRSV; moreover, CCL2 and CCL5 production was greatly reduced and no apparent disease or pulmonary cellular infiltration was observed. However, Gmem rRSV-infected mice developed good antibody responses and were fully protected against subsequent intranasal challenge with parental virus. Even in mice sensitized to G by cutaneous infection with recombinant vaccinia expressing G, intranasal challenge with Gmem rRSV caused insignificant disease. We conclude that secreted G is a key viral product assisting virus replication in vivo, enhancing CCL2 and CCL5 production and promoting illness. Engineered RSV mutants lacking the ability to secrete G are thus promising vaccine candidates.
Maher
Caroline F
CF
Respiratory Medicine, Imperial College, St. Mary's Campus, Norfolk Place, London W2 1PG, UK.
Hussell
Tracy
T
Blair
Edward
E
Ring
Christopher J A
CJ
Openshaw
Peter J M
PJ
D000818:Animals; D002460:Cell Line; D018932:Chemokine CCL2 / Q000378:metabolism; D006224:Cricetinae; D006801:Humans; D018928:Immunity, Mucosal; D008168:Lung / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D011995:Recombination, Genetic; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology / Q000517:prevention & control*; D022261:Respiratory Syncytial Virus Vaccines / Q000008:administration & dosage / Q000276:immunology*; D018113:Respiratory Syncytial Virus, Human / Q000235:genetics / Q000472:pathogenicity*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D014779:Virus Replication
C111835:CCL2 protein, human; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D022261:Respiratory Syncytial Virus Vaccines; D014764:Viral Proteins