Good news on the human immune response to the coronavirus

Comparing infected patients with those who have not been exposed to the coronavirus, this team went through the list of 25 viral proteins that it produces. In the CD4+ cells, the Spike protein, the M protein, and the N protein stood out: 100% of the exposed patients had CD4+ cells that responded to all three of these. There were also significant CD4+ responses to other viral proteins: nsp3, nsp4, ORF3s, ORF7a, nsp12 and ORF8. The conclusion is that a vaccine that uses Spike protein epitopes should be sufficient for a good immune response, but that there are other possibilities as well – specifically, adding in M and N protein epitopes might do an even more thorough job of making a vaccine mimic a real coronavirus infection to train the immune system.

As for the CD8+ cells, the situation looked a bit different. The M protein and the Spike protein were both strong, with the N protein and two others (nsp6 and ORF3a) behind it. Those last three, though, were still about 50% of the response, when put together, so there was no one single dominant protein response. So if you’re looking for a good CD8+ response, adding in epitopes from one or more of those other proteins to the Spike epitope looks like a good plan – otherwise the response might be a bit narrow.