[https://www.science.org/doi/10.1126/sciimmunol.ade2798](https://www.science.org/doi/10.1126/sciimmunol.ade2798)
The study above does not answer these questions and indeed proposes that further research should consider related questions about the effects of the Sarscov2 vaccine, but I am curious more about IgG4 aside from the above study–is it better to have a higher prevalence of IgG3 and IgG1 for defending against viruses? What would happen if there were a higher prevalence of IgG4 from a theoretical medical perspective? What would the effects on defending against viruses be?
In: 5
This question is better suited for r/askscience, the folks over there are experts on topics like this. I’d try posting this question over there.
Did you post this elsewhere? I want to follow.
They kinda say it at the end of the abstract:
>Importantly, this class switch [to IgG4] was associated with a reduced capacity of the spike-specific antibodies to mediate antibody-dependent cellular phagocytosis and complement deposition. Since Fc-mediated effector functions are critical for antiviral immunity, these findings may have consequences for the choice and timing of vaccination regimens using mRNA vaccines, including future booster immunizations against SARS-CoV-2.
All antibodies have a variable domain, the Fab (fragment antigen-binding) and a constant domain, the Fc (fragment constant). The IgG4 Fc fits onto different Fc receptors than IgG1 and 3’s Fcs, and those latter two are much better at inflammatory signaling. Hence, the IgG4 versions of SARS2 spike-binding IgGs are less potent at triggering *antibody-dependent cellular phagocytosis* (functioning as “eat me” tags) and *complement deposition* (attracting complement molecules that further assist in marking viral particles and attracting immune cells to deal with them).
What this really means in practice, though, is hard to say. I believe it’s not quite completely understood what IgG4 signalling does.
Source: researcher on SARS2 serology projects, my boss sent me this exact paper the other day but I haven’t read beyond the abstract yet because christmas break.
E: minor addition about complement
This really helped to explain the various antibodies and their role with our immune system. Goes further into IgG4 and covid. It’s concerning and definitely an issue to watch out for. [https://www.coffeeandcovid.com/p/the-wrong-antibody-monday-december](https://www.coffeeandcovid.com/p/the-wrong-antibody-monday-december)
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