COVID-19 vaccine induces broad antibody, T cell functions with two-dose regimen: Oxford

Researchers at Oxford University on December 17 said that its COVID-19 vaccine manufactured by AstraZeneca induces broad antibody and T cell functions with a two-dose regimen. The university cited data from the Phase I/II clinical trials of the ChAdOx1 nCoV-19 coronavirus vaccine as evidence in an official release. According to the findings published in the journal Nature Medicine, the University of Oxford said that in order to achieve the immune response from its experiment candidate, the pharmaceutical firm AstraZeneca activated two key elements of the immune system. First, the neutralizing antibody against the coronavirus spike protein, and second the robust T cell mechanism. 

“This highly detailed analysis of the immune responses to ChAdOx1 nCoV-19 further underpins the potential of this vaccine to induce protection against COVID-19 disease and provides additional reassurance of the safety of this approach,” lead author of one of the papers, Professor Katie Ewer said in the release.

Citing the recent data from its subsequent phase III trials, she said, that the advanced immunological techniques helped the researchers understand the cellular and antibody-mediated mechanisms that contribute to the protection afforded by the AstraZeneca vaccine. According to Oxford, the researchers investigated the two booster dose schedules in Phase III trials.

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‘Dose sparing’ strategy

Participants were administered with a standard dose, which was followed by a second full standard dose and a separate standard dose followed by a lower dose. The university called the regimen a  ‘dose sparing’ strategy. “Researchers show lower reactogenicity such as sore arm to either booster dose, and increased immune system responses,” Oxford claimed. It stated that AstraZeneca shifted to the two-dose regimen in its ongoing Phase III trials.

Booster doses induce a more robust antibody response than a single dose, Oxford proposed, adding that many notable antibody functions were also triggered by the vaccine. The researchers also detailed the T cell and antibody responses generated by ChAdOx1 nCoV-19 in the report. They further stated that the ChAdOx1 nCoV-19 vaccine-induced Th1 cytokines rather than Th2 cytokines. Th1 cytokines allowed the T cells in the participant’s body to generate ‘signals’ to the rest of the immune system to fight the SARS-coV-2.

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