Cellular killing of microfilariae of Onchocerca volvulus: eosinophil and neutrophil-mediated immune serum-dependent destruction

• Published in: The Journal of immunology (1950) Vol. 127; no. 4; pp. 1611 - 1618
• Main Authors: Greene, B M, Taylor, H R, Aikawa, M
• Format: Journal Article
• Language: English
• Published: United States 01.10.1981
• Subjects: Animals; Antibodies - classification; Binding Sites, Antibody; Cell Adhesion; Cytotoxicity, Immunologic; Eosinophils - immunology; Guinea Pigs; Humans; Immune Sera; Microfilariae - immunology; Microfilariae - ultrastructure; Neutrophils - immunology; Onchocerca - immunology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.127.4.1611

A system that demonstrates in vitro cell-mediated killing of microfilariae of O. volvulus has been developed, using cryopreserved nodule material from endemic areas as the source of microfilariae (Mf). In the presence of immune serum, normal neutrophils and eosinophils, purified using a discontinuous metrizamide gradient, showed enhanced adhesion to Mf, which led to their immobilization and destruction over a 6-to 18-hr period. Peripheral blood mononuclear cells did not attach to or kill Mf. Immunofluorescent staining revealed IgG binding to the surface of microfilariae after incubation in immune serum, but no IgM, IgA, or IgE. The addition of fresh normal human serum (FNHS) increased eosinophil-mediated killing from 50 to 68 and neutrophil killing from 44 to 62. The biologic relevance of Mf obtained from cryopreserved nodules was confirmed in experiments using fresh skin-derived Mf and cells from infected individuals in West Africa. These experiments gave similar results except that cell-mediated killing was consistently increased by the addition of fresh serum alone, without immune serum.