Open AccessEffect of genetic background and delivery route on the preclinical properties of a live attenuated RSV vaccine
Author(s) -
Rachel Groppo,
Joshua DiNapoli,
Kwang Sik Jeong,
Michael Kishko,
Nicholas Jackson,
Harold Kleanthous,
Simon Delagrave,
Lig Zhang,
Mark Parrington
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0199452
Subject(s) - immunogenicity , medicine , attenuated vaccine , immunization , immunity , immunology , nasal administration , virology , neutralizing antibody , antibody , immune system , biology , gene , genetics , virulence
A safe and effective vaccine against RSV remains an important unmet public health need. Intranasally (IN) delivered live-attenuated vaccines represent the most extensively studied approach for immunization of RSV-naïve infants and children, however, achieving an effective balance of attenuation and immunogenicity has proven challenging. Here we report pre-clinical immunogenicity and efficacy data utilizing a live-attenuated vaccine candidate, RGΔM2-2, which was obtained by deleting the M2-2 open reading frame from the genome of the MSA1 clinical isolate. Intramuscular (IM) administration of RGΔM2-2 in cotton rats induced immunity and protective efficacy that was comparable to that induced by intranasal (IN) immunization. In contrast, the protective efficacy of RGΔM2-2 delivered by the IM route to African green monkeys was substantially reduced as compared to the efficacy following IN administration, despite comparable levels of serum neutralizing antibodies. This result suggests that mucosal immunity may play an important role in RSV protection. The RGΔM2-2 vaccine also demonstrated different attenuation profiles when tested in cotton rats, non-human primates, and a human airway epithelial (HAE) cell model. The data suggest RGΔM2-2 is less attenuated than a similarly designed vaccine candidate constructed on the A2 genetic background. These findings have important implications with regard to both the design and the preclinical safety testing of live-attenuated vaccines.