IL17A and tuberculosis: As discussed above, it has been found that IL-17 levels in blood in both humans and cattle correlate with protection against mycobacterial exposure [23] and mycobacterial infection [24] respectively, so it may be, as proposed by Torrado and Cooper [35], that while IL-17 may be essential in vaccine-induced control of TB disease, it needs to be under tight regulation by other aspects of the immune response in order to avoid induction of immunopathology.