Celartics Biopharma today announced that they have achieved major milestones and encouraging results in developing a new generation of mRNA vaccine, CA-R03, designed to prevent infection from SARS-COV-2 virus. The study results have demonstrated that this newly designed mRNA vaccine is highly effective in inducing high levels of neutralizing antibodies and potent viral antigen-specific T cell immunity in preclinical studies. The antibodies induced by CA-R03 has a great capacity to cross-neutralize fast-spreading variants including Delta and Omicron.
"This is one of the major milestones, and we are encouraged by the positive results from CA-R03, demonstrating that LNP-encapsulated mRNA encoding the receptor binding domain of SARS-CoV-2 elicits both cellular and humoral anti-viral responses. Such dual-response is the key to foster a broad and long-lasting protective immunity in humans," said Run-Sheng Chen, an academician of Chinese Academy of Science and Chief Science Officer at Celartics Biopharma. "The cross-neutralization to pathogenic variants of SARS-CoV-2 and induction of powerful cross-reactive T cells are crucial benefits in controlling the pandemic as viral variants continue to evolve. Although we are still in the early stages of studying this vaccine, our data validate that this innovative mRNA vaccine platform has the potential to develop a broad spectrum of vaccine products beyond CA-R03."
The first-generation vaccines encoding whole spike protein, the coat of SARS-CoV-2 virus, are intended to induce neutralizing antibodies to prevent infection. Those vaccines, regardless of their formats such as mRNA, inactivated virus or recombinant protein, have already proven their effectiveness in reducing the rate of severe diseases. However, recent studies indicate that those earlier version vaccines do not efficiently prevent infection of viral variants, as evidenced by significant numbers of breakthrough infections by the Omicron variant. Besides, the protection by those vaccines is short-lived, and repeated booster shots are necessary. Furthermore, the spike protein itself is a sinister component of SARS-CoV-2 and may be potentially associated with various vaccine side effects such as microembolism and myocarditis. Keeping these accumulative research findings in mind, the scientific community is racing to develop more effective and safer vaccines, in recognizing that the pandemic is causing huge loss of human lives.
While neutralizing antibody is the frontline fighter, T cell immunity is crucial for long-term protection. Retrospectively reviewed on the data of SARS-1 endemic in 2003, studies find that the virus-specific antibodies are disappeared whereas the protective T cell response remains detectable even after 17 years post-infection among SARS survivors. Unlike antibody response that is susceptible to viral genetic mutations, T cells can recognize conserved viral peptides bound to HLA molecules, thereby eliminating virus-infected cells and leaving virus no place to multiply and mutate. Ultimately, some T cells are acquiring their memory and can be reactivated instantly whenever encountering new entry of virus in keeping the virus in check. Celartics Biopharma is specializing in dendritic cell technology and targeting endogenous DC cells in vaccine design is a logical approach.
The CA-R03 vaccine is specially designed to target the Delta and Omicron variants of SARS-CoV-2. The LNP delivery platform that Celartics Biopharma has used enables highly stable storage of the vaccine and efficient mRNA vaccine delivery into experimental animals and humans. "Our preclinical studies have proven that the vaccine can yield high titer of neutralizing antibodies with five folds over the level from major competitors," commented Professor Chen. "The vaccine can also efficiently promote antigen-specific CD8+ T cell response." Impressive antigen-specific T cell response is observed in this vaccine, about ten times...
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