The BioNTech / Pfizer vaccine BNT162b2 induces class-switched SARS-CoV-2-specific plasma cells and potential memory B cells as well as IgG and IgA serum and IgG saliva antibodies upon the first immunization
https://www.medrxiv.org/content/10.1101/2021.03.10.21252001v1
We show that the vaccine induces in particular anti-SARS-CoV-2-S IgG1 and IgG3 as well as IgA1 and in some individuals also IgG2 and IgA2 serum Abs. In the saliva, we found no anti-SARS-CoV-2-S IgA, but instead IgG Abs. Furthermore, we found SARS-CoV-2-S reactive IgG+ blood PCs and potential memory B cells as well as SARS-CoV-2-S reactive IgA+ PCs and/or potential memory B cells in some individuals.
Our data suggest that the vaccine induces a promising CD4+ T cell-dependent systemic IgG1 and IgG3 Ab response with IgG+ PCs and potential memory B cells. In addition to the systemic IgG response, the systemic IgA and saliva IgG response might help to improve a first line of defense in the respiratory tract against SARS-CoV-2 and its mutants.
Unexpected, valuable antibody types discovered
To immunologist Ziv Shulman of the Weizmann Institute of Science in Israel, the team’s data are a good sign that the vaccine is having its intended effect in people. What he finds surprising, he says, is the additional discovery of an unexpected type of spike-targeting plasmablast in the recipients’ lymph nodes. In this study, while most plasmablasts produced IgG antibodies—which circulate in the blood—a substantial portion made IgA antibodies, which are normally produced in infected mucosal tissues, such as in the gut or nose.
It’s entirely unexpected to see IgA antibodies produced after a vaccine is injected into muscle tissue in the body’s periphery—he’d only expect that for vaccines that are administered through mucosal tissues, such as the mouth or nose, says Shulman, who was not involved in the study. But their presence is a good thing. Most likely they will migrate into mucosal tissues and provide protection there—which IgG antibodies are also capable of doing, but not as efficiently. “[The IgAs] could block entry of the virus at the site where it goes into our body,” says Shulman. The exact source of those IgA-expressing plasmablasts—for instance, whether they originate from germinal center reactions induced by the vaccine or from reawakened memory immune cells from previous common cold–causing coronavirus infections—is unclear, he notes.
你的帖子，一如既往，有太多的想象和推测。
