Researchers from the University of Oxford (United Kingdom) have published this Thursday more datos of phase I / II clinical trials of your vaccine against the coronavirus ‘ChAdOx1 nCoV-19’, developed with AstraZeneca, showing that stimulates a broad antibody and T cell response and has the best immune response when using a two full dose regimen. These findings are published in two articles, both published in the peer-reviewed journal Nature Medicine.
Previous studies have shown that developing any vaccine against the SARS-CoV-2 coronavirus is necessary activate two key elements of the immune system: a neutralizing antibody against the coronavirus spike protein, which is likely to be critically important for protection against disease, as well as robust T-cell responses.
“This highly detailed analysis of immune responses to the vaccine further strengthens the potential of this vaccine to induce protection against COVID-19 disease and provides an additional assurance of the safety of this approach. Using these advanced immunological techniques, we can better understand the different cellular and antibody-mediated mechanisms that contribute to the protection offered by this vaccine, as demonstrated by recent data from subsequent Phase 3 trials, “said Katie Ewer, one of the main authors.
One of these articles outlines the early stage planning involving the design of phase III trials to investigate two booster dose schedules, a standard dose followed by a second standard dose and a standard dose followed by a lower dose (investigated to determine if this might be a viable “dose saving” strategy).
Furthermore, the researchers show less reactogenicity (for example, a sore arm) in either booster dose and an increase in immune system responses; these data were used to support the switch to a two-dose regimen in ongoing phase III trials.
“It has been shown that booster doses of the vaccine induce stronger antibody responses than a single dose, and that the standard dose induces the best response, supporting the earlier decision to move to a two-dose vaccine regimen in phase III clinical trials, “the researchers explain. The article also shows that the vaccine triggers many different antibody functions that may be important for protection against disease.
In the second document, the authors detail a extensive investigation of the T cell responses and antibodies generated by your vaccine candidate. Specifically, they report that proteins known as cytokines that allow T cells to generate ‘signals’ for the rest of our immune system, produced by the body’s immune system in response to the vaccine, predominantly induce Th1 cytokines rather than cytokines. Th2.
The authors also report the induction of a subset of T cells, which is known to be particularly effective in clearing virus-infected cells from the body during infection. “This type of T cell response, in combination with the detailed antibody profile, is highly favorable for an effective vaccine, and further supports the profile of this vaccine as a safe vaccine,” they conclude.
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