A vaccine against the MERS (Middle East Respiratory Syndrome) coronavirus induces an immune response in two animal models, the mouse and the rhesus monkey.
American experts may have found a weapon against the MERS (Middle East Respiratory Syndrome) coronavirus. A team from the National Institute of Health (NIH) described in Nature Communications the mode of action of a vaccine candidate against this respiratory virus. The trials on mice and the rhesus macaque are encouraging.
“The current immunization strategy is the first to induce antibodies neutralizing MERS-CoV which targets multiple epitopes”, specify the authors of the study. Five vaccine candidates have been tested in mice. All target a viral protein, the spike glycoprotein, which the coronavirus uses to enter cells. Vaccines work in two stages: the first injection activates the immune system, the second boosts it.
Less sick monkeys
The vaccinated mice exhibited a positive immune response and massively produced antibodies against several strains of MERS-CoV. The researchers selected the three most effective models and tested them on different groups of rhesus macaques. The 18 animals (12 vaccinated) were exposed to the MERS coronavirus 19 weeks after the second injection.
“Rhesus macaques do not show open clinical signs,” say the authors. However, they develop lower respiratory tract infections, with pulmonary infiltrations. The unvaccinated monkeys exhibited more marked lung abnormalities than the vaccinated animals. This means that the pneumonia runs deeper and lasts longer without immunization.
The approach is promising, but needs to be refined before human trials. However, it demonstrates the good understanding of the mechanism of action of this coronavirus which appeared in April 2012, which caused 480 deaths in 35 countries.
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