Perturbation of lymphocyte circulation in experimental murine leprosy. I. Description of the defect.

Infection of Lewis rats with Mycobacterium lepraemurium is characterized by granulomatous pathology primarily involving the paracortical areas of lymph nodes and periarteriolar lymphocyte sheaths of the splenic white pulp. Intravenous infusion of radiolabeled thoracic duct lymphocytes (TDL)2 from normal syngeneic donors failed to produce a significant increase of cell output and radioactivity in the thoracic duct lymph of infected rats as compared with a marked increase in matched control recipients. Conversely, the migration of TDL from infected donor rats was normal in uninfected control rats that had been infused with serum from infected donors. The onset of the lymphocyte traffic disturbance takes place between 2 and 6 weeks after inoculation of viable M. lepraemurium. However, inoculation of heat-killed organisms produces little perturbation of lymphocyte circulation. Thus, the abnormal circulation of TDL in rats with active infection appears to be secondary to granulomatous pathology in lymphoid organs that disturbs cell traffic through these organs.