9873210 wrote:Can N antibodies actually prevent an infection? I thought the N proteins are tucked away inside the virus and so it can't be recognized until the virus gets into a cell (or the virus is disrupted by other means).
Is there a definition of "infection" that is broader that gets inside a cell? E.g. it's not considered an infection until there is some level of transmission from cell to cell.
Excellent questions.
Re effect on N antibodies I don’t know, in fact I wonder whether the scientific community knows yet(*), but I was using N antibodies more as a proxy for the nature of the S antibodies rather than in their own right hence my specific calling out of “vaccine induced” in my “when we are talking about keeping down total case numbers vaccine induced antibodies, at least from the current set of vaccines, are pretty much irrelevant” qualification. N is currently indicative of infection-induced adaptive immune response since the current vaccines only expose the host to the spike protein so if N antibodies are present then S antibodies will also be present but will not have come solely from a Covid-19 vaccine so might be less keyed to the original strain. Also there i evidence that even with only vaccine-induced S antibodies the booster (giving a minimum third exposure to identical wild-strain(ish) spike antigen) not only boosts immediate circulating antibody levels for a while but also increases breadth i.e. neutralising effect against multiple variants. Putting all that together it’s also at least a plausible theory that someone with N antibodies might have the breadth of action of their originally vaccine-induced S antibodies further broadened by pre or post vaccination infection. Bottom line is that I think it might at least not be absurd to suggest that some subset of the people with N antibodies might have S antibodies that have more effective neutralisation wrt the currently dominant circulating strains than those people who only acquired their S antibodies from vaccination. That increased neutralisation would be especially true for those who acquired their N antibodies from Omicron infection.
Oh, and I suppose it is at least conceivable that certain N antibodies might be neutralising. If certain N antibody bindings were such that the RNA was compromised due to messing up its nucleocapsid packaging that could mean that even though spike allows the virus to make the interface with a host cell such that the viral particle’s RNA could be injected into a host cell (by membrane fusion or, I think more favoured by Omicron, by endocytosis) maybe a prior N antibody binding could make that RNA unviable. Actually, I wonder if that might feed into your second question re the definition of infection. I assume that a replication deficient virus can still inject its RNA or DNA into a host cell but because certain genes have been knocked out by the vaccine designers it won’t be able to spawn new viral particles from within the “infected” cell. I don’t know the answer but you definitely raise an interesting question re the definition of infection.
- Julian
(*) In the last 6 months or so I’ve tried to dig at least one level deeper into the science by buying a few text books and following YouTube channels such as “This Week in Virology” (TWIV). I’m under no illusion that I understand this stuff, I have a pitifully skin-deep understanding of the basic concepts compared to people who have dedicated their adult lives to the various relevant disciplines, but one of the big things I’ve noticed is just how much more frequently I hear “we just don’t know” comments vs the I suspect false authority we are often presented with by the mainstream media. There is still a huge amount to understand about this wretched virus. The TWIV folks in particular often rage against the obsession with spike and the lack of research on the actions of the various non-structural proteins.
