DELTA variant. To discuss this, let's actually start with discussing the spike protein of the virus. Remember, the spike protein of the virus is how the virus binds to our host cell. The spike protein is the protein that is encoded by the mRNA & adenovirus-DNA vaccines (J&J)
The vaccine gives you genetic material that enables YOU to make that spike protein and then you raise an immune response against it (of course natural infection makes you raise an immune response against virus). Genetic material goes away & you have immune response. J&J just one
step "upstream" from mRNA vaccines so gives you DNA which you MAKE into mRNA and then you make spike protein. mRNA vax allows you to make protein directly. Not that different though J&J vax takes longer to give full immunity (phase II trial, up to 60
Okay, now consider this fact: you make at LEAST 87 T cells that line up across the spike protein to combat the virus from a vaccine (will explain 87 in bit). And likely many more. T cell measurement takes fancy machines, show you the breadth of the T cell response.
So, this paper is by our CA colleagues @settelab shows you make T cells against 1400 little bits of the virus and postulates 100 or more across the spike protein (enriched for spike protein T cells). And the paper from the AztraZeneca trial in S.