Before revision:  While the clonal selection of the T helper (Th) cells is the simple and established mechanism for learning a better recognition of new pathogens, the question  still remains unexplored is how the Th cells can learn to eliminate them by activating or deactivating appropriate immune cells after recognition .
After revision:  While the clonal selection of the T helper (Th) cells is the simple and established mechanism for learning a better recognition of new pathogens, the question still remains unexplored is how the Th cells can acquire better ways to bias the responses of immune cells for eliminating pathogens more efficiently by translating the recognized antigen information into regulatory signals .