The role of Mycobacterium w (
Mw) vaccine as an
immunomodulator and immunoprophylactant in the treatment of mycobacterial diseases (
leprosy and
pulmonary tuberculosis) is well established. The fact that it shares common
antigens with leishmanial parasites prompted its assessment as an
immunostimulant and as an adjunct to known anti-leishmanials that may help in stimulating the suppressed immune status of Leishmania donovani-infected individuals. The efficacy of
Mw vaccine was assessed as an
immunomodulator, prophylactically either alone or in combination with anti-leishmanial
vaccine, as well as therapeutically as an adjunct to anti-leishmanial treatment in L. donovani-infected hamsters, representing a chronic human
Visceral Leishmaniasis (VL) model. Similarly, its efficacy was also evaluated in L. donovani-infected BALB/c mice, representing an acute VL model. The preliminary studies revealed that Mw was ineffective as an
immunostimulant and/or immunoprophylactant in hamsters infected with L. donovani, as estimated by T-cell immunological responses. However, in the BALB/c mice-VL model it appeared as an effective
immunostimulant but a futile prophylactic agent. It is therefore inferred that, contrary to its role in managing
tuberculosis and
leprosy infections,
Mw vaccine has not been successful in controlling VL
infection, emphasizing the need to find detailed explanations for the failure of this
vaccine against the disease.