In ELISpot, positive controls serve the dual purpose of demonstrating the functionality of the assay system as well as the quality of the cells used.
The anti-CD28 mAb can be used, together with antigen, to co-stimulate specific T cells. The anti-CD28 mAb can also be used together with anti-CD3 mAb for polyclonal activation of T cells. Suitable anti-CD3 mAbs to use are mAb CD3-2 for human T cells and mAb CD3-1 for macaque T cells. The recommended concentration of anti-CD28 mAb for either application is 0.1 ug/ml.