Eosinophils are the major effector cells of immunity to microfilariae in a mouse model of onchocerciasis.
Mice inoculated with microfilariae of the filarial nematode Onchocerca lienalis clear their parasites over a period of 3-4 months and are highly resistant to re-infection. We have investigated the comparative roles of the eosinophil, macrophage and neutrophil in effecting this parasite clearance, employing agents specifically to perturb cell function in vivo. Using the anti-IL-5 monoclonal antibody TRFK-5, we show that eosinophils are of primary importance in effecting resistance to re-infection. Ablation of macrophages (with carbon) and neutrophils (with the monoclonal antibody NIMP-R14) had no effect on parasite clearance following re-infection. Neutralization of these 3 cell types during a primary infection showed that while the removal of both eosinophils and macrophages caused a small but significant delay in parasite clearance, the depletion of neutrophils had no effect. This report describes the first direct evidence for eosinophil-mediated killing of microfilariae in vivo, and is consistent with Th-2 cell responses previously described in this model.
Folkard
S G
SG
Liverpool School of Tropical Medicine, UK.
Hogarth
P J
PJ
Taylor
M J
MJ
Bianco
A E
AE
D000818:Animals; D000911:Antibodies, Monoclonal; D002417:Cattle; D002418:Cattle Diseases; D016009:Chi-Square Distribution; D004195:Disease Models, Animal; D004804:Eosinophils / Q000276:immunology*; D007113:Immunity, Innate; D015848:Interleukin-5 / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D009504:Neutrophils / Q000276:immunology; D009855:Onchocerciasis / Q000097:blood / Q000276:immunology* / Q000662:veterinary; D051381:Rats; D012008:Recurrence
D000911:Antibodies, Monoclonal; D015848:Interleukin-5