Enhanced protective efficacy of H5 subtype influenza vaccine with modification of the multibasic cleavage site of hemagglutinin in retroviral pseudotypes

Abstract

Traditionally, the multibasic cleavage site (MBCS) of surface protein H5-hemagglutinin (HA) is converted to a monobasic one so as to weaken the virulence of recombinant H5N1 influenza viruses and to produce inactivated and live attenuated vaccines. Whether such modification benefits new candidate vaccines has not been adequately investigated. We previously used retroviral vectors to generate wtH5N1 pseudotypes containing the wild-type HA (wtH5) from A/swine/Anhui/ca/2004 (H5N1) virus. Here, we generated mtH5N1 pseudotypes, which contained a mutant-type HA (mtH5) with a modified monobasic cleavage site. Groups of mice were subcutaneously injected with the two types of influenza pseudotypes. Compared to the group immunized with wtH5N1 pseudotypes, the inoculation of mtH5N1 pseudotypes induced significantly higher levels of HA specific IgG and IFN-γ in immunized mice, and enhanced protection against the challenge of mouse-adapted avian influenza virus A/Chicken/Henan/12/2004 (H5N1). This study suggests modification of the H5-hemagglutinin MBCS in retroviral pseudotypes enhances protection efficacy in mice and this information may be helpful for development of vaccines from mammalian cells to fight against H5N1 influenza viruses.

Pseudotype-Based Neutralization Assays for Influenza: A Systematic Analysis

“…Murine leukemia virus cores are less widely used but provide similar gag and pol elements to HIV vectors (32)(33)(34)(35)(36)(37)(38). One MLV core used consists of gag and pol under the effect of a CMV promoter, a vector which has been shared across various laboratories (39)(40)(41).…”

“…Furthermore, the correlation between H5 MN and H5 pMN allowed the establishment of a threshold from which pMN titers could be based. pMN data were then analyzed based on the threshold, which showed protective titers in patients of [38][39][40][41][42][43]54, and 79% after adjuvanted vaccination, second dose and booster, respectively (137). = 0.6491, p < 0.0001).…”

Stability of Retroviral Vectors Against Ultracentrifugation Is Determined by the Viral Internal Core and Envelope Proteins Used for Pseudotyping

“…In this study, we quantified the stabilities of retroviral and lentiviral vectors pseudotyped with influenza virus envelope proteins, hemagglutinin (HA) and neuraminidase (NA), against ultracentrifugation. Retroviral and lentiviral vectors with the influenza virus surface proteins can be used in studies to advance influenza virus vaccines ( Tao et al, 2013 ), develop novel detection systems for newly emerging influenza viruses ( Lim et al, 2015 ), and deliver genes to cells of airway tissues. The stabilities of retroviral and lentiviral vectors pseudotyped with HA and NA were compared with those of vectors displaying VSVGs, which are known to be relatively stable against ultracentrifugation.…”