Leprosy: understanding protective immunity.

Analyses of these recombinant proteins as antigens represent the beginning of understanding the chemical nature of epitopes of M. leprae. Their role in protective immunity remains to be elucidated. The available models for analysing protective immunity include infection with M. leprae in the mouse footpad, in immuno-deficient mice, in armadillos and certain susceptible primates. None is completely satisfactory and only the mouse footpad has been applied to assess the protective efficacy of individual antigens. The workshop emphasized that the gulf between understanding immunogenicity and protective immunity is wide. Bridging this gulf is essential for the rational design of a new generation vaccine against leprosy.