Also, what he's saying about how antibodies work isn't quite right. When I worked in a lab developing vaccines, I observed a common methodology was to present multiple antigens to the body to try to generate immunoproliferation against an antigen that the body refused to mount an immune response to on its own.

For example, we were working on a vaccine for dental caries, or cavities, caused by Streptococcus mutans. The compound that was being tested was a chimera of one of the non-toxic subunits of cholera toxin paired with what they call AgI/II surface protein from S. mutans. The theory there is that cholera toxin is immunoproliferative, so presenting it to the body paired with AgI/II should hopefully generate antibodies to S. mutans without cholera toxin present, thus curing people of cavities using the body's own immune system.

This is also how an adjuvant works, which I believe is used in all vaccines. You inject the adjuvant, which typically causes some sort of inflammation response or immunoproliferative response, in the same concoction that is used to present your vaccine, and so it primes the body to attack it, generating memory for that antigen.

We were working with mice, and I don't know where the research went after I left, but I do know that it's a common strategy for vaccine development, or at least it was a decade and a half ago. What this means is that if you were to create a virus with 3 different antigens like he says, the body would have an even stronger immunoproliferative reaction to all of the antigens, not the other way around. An antibody won't pick which thing it will stick to. It's pure chance, and it's just as likely to be specific for parts of two antigens as it is to be specific to just one. That's why the above vaccine strategy works in generating immuno memory.