Respiratory Syncytial Virus (RSV) is an important viral agent causing severe respiratory tract disease in infants and children as well as in the elderly and immunocompromised individuals. The lack of a safe and effective RSV vaccine represents a major unmet medical need. RSV fusion (F) surface glycoprotein was modified and cloned into a baculovirus vector for efficient expression in Sf9 insect cells. Recombinant RSV F was glycosylated and cleaved into covalently linked F2 and F1 polypeptides that formed homotrimers. RSV F extracted and purified from insect cell membranes assembled into 40 nm protein nanoparticles composed of multiple RSV F oligomers arranged in the form of rosettes. The immunogenicity and protective efficacy of purified RSV F nanoparticles was compared to live and formalin inactivated RSV in cotton rats. Immunized animals induced neutralizing serum antibodies, inhibited virus replication in the lungs, and had no signs of disease enhancement in the respiratory track of challenged animals. RSV F nanoparticles also induced IgG competitive for binding of palivizumab neutralizing monoclonal antibody to RSV F antigenic site II. Antibodies to this epitope are known to protect against RSV when passively administered in high risk infants. Together these data provide a rational for continued development a recombinant RSV F nanoparticle vaccine candidate.
References
[1]
Kim HW, Canchola JG, Brandt CD, Pyles G, Chanock RM, et al. (1969) Respiratory syncytial virus disease in infants despite prior administration of antigenic inactivated vaccine. Am J Epidemiol 89: 422–434.
[2]
Crowe JE Jr, Williams JV (2003) Immunology of viral respiratory tract infection in infancy. Paediatr Respir Rev 4: 112–119.
Graham BS (2011) Biological challenges and technological opportunities for respiratory syncytial virus vaccine development. Immunol Rev 239: 149–166.
[5]
Murata Y (2009) Respiratory syncytial virus vaccine development. Clin Lab Med 29: 725–739.
[6]
Connors M, Collins PL, Firestone CY, Murphy BR (1991) Respiratory syncytial virus (RSV) F, G, M2 (22K), and N proteins each induce resistance to RSV challenge, but resistance induced by M2 and N proteins is relatively short-lived. J Virol 65: 1634–1637.
[7]
Collins PL CJ (2007) Respiratory Syncytial Virus and Metapneumovirus. Fields Virology: 1601–1646.
[8]
Beeler JA, van Wyke Coelingh K (1989) Neutralization epitopes of the F glycoprotein of respiratory syncytial virus: effect of mutation upon fusion function. J Virol 63: 2941–2950.
[9]
Carbonell-Estrany X, Simoes EA, Dagan R, Hall CB, Harris B, et al. (2010) Motavizumab for prophylaxis of respiratory syncytial virus in high-risk children: a noninferiority trial. Pediatrics 125: e35–51.
[10]
Sandritter T (1999) Palivizumab for respiratory syncytial virus prophylaxis. J Pediatr Health Care 13: 191–195; quiz 196–197.
[11]
McLellan JS, Chen M, Kim A, Yang Y, Graham BS, et al. (2010) Structural basis of respiratory syncytial virus neutralization by motavizumab. Nat Struct Mol Biol 17: 248–250.
[12]
McLellan JS, Yang Y, Graham BS, Kwong PD (2011) Structure of respiratory syncytial virus fusion glycoprotein in the postfusion conformation reveals preservation of neutralizing epitopes. J Virol 85: 7788–7796.
[13]
Swanson KA, Settembre EC, Shaw CA, Dey AK, Rappuoli R, et al. (2011) Structural basis for immunization with postfusion respiratory syncytial virus fusion F glycoprotein (RSV F) to elicit high neutralizing antibody titers. Proc Natl Acad Sci U S A 108: 9619–9624.
[14]
Calder LJ, Gonzalez-Reyes L, Garcia-Barreno B, Wharton SA, Skehel JJ, et al. (2000) Electron microscopy of the human respiratory syncytial virus fusion protein and complexes that it forms with monoclonal antibodies. Virology 271: 122–131.
[15]
Pushko P, Tumpey TM, Van Hoeven N, Belser JA, Robinson R, et al. (2007) Evaluation of influenza virus-like particles and Novasome adjuvant as candidate vaccine for avian influenza. Vaccine 25: 4283–4290.
[16]
Prince GA, Curtis SJ, Yim KC, Porter DD (2001) Vaccine-enhanced respiratory syncytial virus disease in cotton rats following immunization with Lot 100 or a newly prepared reference vaccine. J Gen Virol 82: 2881–2888.
[17]
Prince GA, Jenson AB, Hemming VG, Murphy BR, Walsh EE, et al. (1986) Enhancement of respiratory syncytial virus pulmonary pathology in cotton rats by prior intramuscular inoculation of formalin-inactiva ted virus. J Virol 57: 721–728.
[18]
Chaiwatpongsakorn S, Epand RF, Collins PL, Epand RM, Peeples ME (2011) Soluble respiratory syncytial virus fusion protein in the fully cleaved, pretriggered state is triggered by exposure to low-molarity buffer. J Virol 85: 3968–3977.
[19]
Johnson S, Oliver C, Prince GA, Hemming VG, Pfarr DS, et al. (1997) Development of a humanized monoclonal antibody (MEDI-493) with potent in vitro and in vivo activity against respiratory syncytial virus. The Journal of infectious diseases 176: 1215–1224.
[20]
Blanco JC, Boukhvalova MS, Shirey KA, Prince GA, Vogel SN (2010) New insights for development of a safe and protective RSV vaccine. Hum Vaccin 6: 482–492.
[21]
Openshaw PJ, Culley FJ, Olszewska W (2001) Immunopathogenesis of vaccine-enhanced RSV disease. Vaccine 20 Suppl 1S27–31.
[22]
Begona Ruiz-Arguello M, Gonzalez-Reyes L, Calder LJ, Palomo C, Martin D, et al. (2002) Effect of proteolytic processing at two distinct sites on shape and aggregation of an anchorless fusion protein of human respiratory syncytial virus and fate of the intervening segment. Virology 298: 317–326.
[23]
Ruiz-Arguello MB, Martin D, Wharton SA, Calder LJ, Martin SR, et al. (2004) Thermostability of the human respiratory syncytial virus fusion protein before and after activation: implications for the membrane-fusion mechanism. J Gen Virol 85: 3677–3687.
[24]
Prince GA, Jenson AB, Horswood RL, Camargo E, Chanock RM (1978) The pathogenesis of respiratory syncytial virus infection in cotton rats. Am J Pathol 93: 771–791.
[25]
Murphy BR, Prince GA, Collins PL, Hildreth SW, Paradiso PR (1991) Effect of passive antibody on the immune response of cotton rats to purified F and G glycoproteins of respiratory syncytial virus (RSV). Vaccine 9: 185–189.
[26]
Kapikian AZ, Mitchell RH, Chanock RM, Shvedoff RA, Stewart CE (1969) An epidemiologic study of altered clinical reactivity to respiratory syncytial (RS) virus infection in children previously vaccinated with an inactivated RS virus vaccine. Am J Epidemiol 89: 405–421.
[27]
Chin J, Magoffin RL, Shearer LA, Schieble JH, Lennette EH (1969) Field evaluation of a respiratory syncytial virus vaccine and a trivalent parainfluenza virus vaccine in a pediatric population. Am J Epidemiol 89: 449–463.
[28]
Prince GA, Prieels JP, Slaoui M, Porter DD (1999) Pulmonary lesions in primary respiratory syncytial virus infection, reinfection, and vaccine-enhanced disease in the cotton rat (Sigmodon hispidus). Lab Invest 79: 1385–1392.
[29]
Murphy BR, Walsh EE (1988) Formalin-inactivated respiratory syncytial virus vaccine induces antibodies to the fusion glycoprotein that are deficient in fusion-inhibiting activity. Journal of clinical microbiology 26: 1595–1597.
[30]
Moghaddam A, Olszewska W, Wang B, Tregoning JS, Helson R, et al. (2006) A potential molecular mechanism for hypersensitivity caused by formalin-inactivated vaccines. Nat Med 12: 905–907.
[31]
Delgado MF, Coviello S, Monsalvo AC, Melendi GA, Hernandez JZ, et al. (2009) Lack of antibody affinity maturation due to poor Toll-like receptor stimulation leads to enhanced respiratory syncytial virus disease. Nat Med 15: 34–41.
[32]
Polack FP, Teng MN, Collins PL, Prince GA, Exner M, et al. (2002) A role for immune complexes in enhanced respiratory syncytial virus disease. J Exp Med 196: 859–865.
