Development of a mouse food pad model for detection of sub clinical leprosy.

Summary Early diagnosis of leprosy and amulti-drug therapy (MDT) regimen willblock the trajectory of nerve damage, disability and deformity that are the hallmarksof this chronic disease. However, the diagnosis of leprosy is made solely byrecognition of clinical signs and symptoms, requiring special expertise. Theselimitations also result in the under reporting of worldwide prevalence and incidencerates for leprosy. Sorely needed is an objective laboratory test for detecting earlyleprosy. As the antigenic burden of M. leprae can be virtually undetectable in earlyclinical leprosy, cell mediated immunity and antibody responses will likely be weak.So the sensitivity of new diagnostic tests is as important as specificity. Major effortsare underway employing recombinant M. leprae antigens and synthetic peptides, todevelop diagnostic assays for early leprosy infection, using in vitro Tcell reactivity orserological tests. We have used the initial phase of the mouse foot pad model as an‘early’ model of leprosy infection to screen Tcell responses against M. leprae specificantigens and synthetic peptides. Unlike human disease in animal models we cancontrol infection progress and monitor bacillary growth relative to time course ofdevelopment of Tcell response to specific M. leprae antigens. The study employedsplenic Tcells instead of draining lymph node Tcells to model the systemic responseas opposed to alocal one. We found that 10