Immunization with Plant-Derived Multimeric H5 Hemagglutinins Protect Chicken against Highly Pathogenic Avian Influenza Virus H5N1

Abstract

Since 2003, H5N1 highly pathogenic avian influenza viruses (HPAIV) have not only caused outbreaks in poultry but were also transmitted to humans with high mortality rates. Vaccination is an efficient and economical means of increasing immunity against infections to decrease the shedding of infectious agents in immunized animals and to reduce the probability of further infections. Subunit vaccines from plants are the focus of modern vaccine developments. In this study, plant-made hemagglutinin (H5) trimers were purified from transiently transformed N. benthamiana plants. All chickens immunized with purified H5 trimers were fully protected against the severe HPAIV H5N1 challenge. We further developed a proof-of-principle approach by using disulfide bonds, homoantiparallel peptides or homodimer proteins to combine H5 trimers leading to production of H5 oligomers. Mice vaccinated with crude leaf extracts containing H5 oligomers induced neutralizing antibodies better than those induced by crude leaf extracts containing trimers. As a major result, eleven out of twelve chickens (92%) immunized with adjuvanted H5 oligomer crude extracts were protected from lethal disease while nine out of twelve chickens (75%) vaccinated with adjuvanted H5 trimer crude extracts survived. The solid protective immune response achieved by immunization with crude extracts and the stability of the oligomers form the basis for the development of inexpensive protective veterinary vaccines.

Safety, Immunogenicity, and Protective Efficacy of an H5N1 Chimeric Cold-Adapted Attenuated Virus Vaccine in a Mouse Model

“…Several prepared H5 candidate vaccines are underway in clinical trials. Th candidates include inactivated H5 vaccines, recombinant HA-based vaccine, spilt virus o subunit vaccine, plant-derived influenza vaccine, insect-cell-derived virus-like particle and live influenza vaccine [40][41][42]. Among the H5 pandemic vaccines, the live influenz vaccine has been studied by various master donors of influenza A and influenza B viruse Live influenza vaccines provide the most cross-protection immune responses [43 Recently, live influenza vaccines from different master donors were cold-adapted.…”

Effects of Size and Surface Properties of Nanodiamonds on the Immunogenicity of Plant-Based H5 Protein of A/H5N1 Virus in Mice

“…The differentiated HA titer is modulated mainly by charge and not size, raising questions about the mechanism of action in vitro experiments. Several reports have demonstrated that higher HA titers are obtained in lower HA protein amounts when the HA antigen size was increased via H5 oligomeric or H5-VLP formation [ 14 , 25 , 26 ]. Thus, H5.c2 antigen size increased after coating negatively charged ND40 and ND100.…”

Producing Vaccines against Enveloped Viruses in Plants: Making the Impossible, Difficult

“…In contrast, a large body of work has described the expression and purification of HA from a variety of serotypes without necessarily attempting to specifically form VLPs, enveloped or otherwise. In some cases, HA has been produced as a fusion to a carrier or oligomerization scaffold to aid immunogenicity [ 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. In these and other studies, protein accumulation was improved by the removal of the HA transmembrane domain (TM) and/or ER retention without compromising immunogenicity or efficacy in animal models [ 48 , 49 , 50 , 51 , 52 , 53 ].…”

“…In some cases, HA has been produced as a fusion to a carrier or oligomerization scaffold to aid immunogenicity [ 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. In these and other studies, protein accumulation was improved by the removal of the HA transmembrane domain (TM) and/or ER retention without compromising immunogenicity or efficacy in animal models [ 48 , 49 , 50 , 51 , 52 , 53 ]. While expression has mainly been achieved through transient expression in Nicotiana leaves, expression of immunogenic HA in tobacco seeds was also shown to be possible [ 54 ], as was the expression of influenza nucleoprotein in maize seeds [ 55 ].…”