IF gamma (and IL-2) are for cell mediated immunity, which would make T cells (and macrophages) the way to go.
Natural killer cells aren't on the humoral arm (for bacteria), so this would work as well, but it's not as clean of a connection. Fun fact: NK cells are used for detecting cancer at the 1 cellular stage, that's why researchers love them. Currently it takes 1 billion cells for the human eye to detect cancer, so you can see why this would be revolutionary in medicine.
