CD4 and tuberculosis: The current approach to TB vaccine development suffers from three shortcomings: 1) it has focused mostly on a narrow set of candidate TB antigens which may have suboptimal activity in protecting against TB; 2) it has focused on generating classical, CD4+ T(h1) cells, which may be essential but not sufficient to generate an optimally protective response; and 3) has not taken into account recently emerging evidence suggesting a role for traditionally “ignored” cells, such as B-cells, in generating immunological protection against TB.