> Through a series of experiments, the researchers found that T cells could indeed self-activate by puckering their cell membrane inwards to allow the B7 protei

> Through a series of experiments, the researchers found that T cells could indeed self-activate by puckering their cell membrane inwards to allow the B7 protein and the CD28 receptor to bind to each other Very cool, but doesn't this imply that T-cells can also activate other T-cells that are nearby? (in trans) Edit: in the actual paper they said "We generated reporter Jurkat lines and Raji APCs stably expressing CD80, CD86, or neither (Figure S2A), enabling coculture conditions in which the B7 ligand was presented to CD28 in cis, in trans, or both. To minimize potential trans-B7:CD28 interactions between T cells, we cultured Jurkat reporter cells with 100-fold excess of Raji APCs" However, the point remains that in vivo, T-cells would be able to do both the cis and trans activation. Which is still novel, I think?