Ultrastructure of human foetal Schwann cells in tissue culture infected withMycobacterium leprae

Abstract

Summary Human Schwann cells from fo etal peripheral nerves were grown in tissue culture and infected with My cobacterium leprae. After fixation fo r electron microscopy the ultrastructural fe atures of infected Schwann cells were studied. The findings reproduce previous ultrastructural findings of adult human Schwann cells in tissue culture and clearly demonstrate that M. leprae infects cultured Schwann cells. Most of the M. leprae remained electron dense, suggesting retained viability, and did not appear to induce any toxic change in the Schwann cells.Infection of the Schwann cell by My cobacterium leprae is considered to be an important factor in the pathogenesis of human leprosy. Ultrastructural observations have confirmed the presence of M. leprae in Schwann cells both in the human diseasel.2 and in armadillos infected with the bacterium.3,4In the last decade there has been considerable progress in tissue culture of various constitutents of peripheral nerves and it is now possible to selectively culture Schwann cells5,6 and ultrastructural observations have been made on such cells.7Recently, cultured human fo etal Schwann cells from peripheral nerves have been successfully infected with M. leprae.8 We now describe the ultrastructural fe atures of these infected cells. Materials and methods TISSUE SAMPLESPresumed healthy human fo etuses of 8 to 20 weeks gestational age were obtained from the tissue bank at the Royal Marsden Hospital. The study of the foetal material was approved by the Ethical Committee of the Brompton Hospital.