Endogenous interleukin-12 is critical for controlling the late but not the early stage of Leishmania mexicana infection in C57BL/6 mice.
The role of interleukin-12 (IL-12) has been clearly established in the resistance of C57BL/6 (B6) mice to Leishmania major infection, but its involvement in the control of Leishmania mexicana infection remains to be determined. Here, we show the following. (i) L. mexicana, in contrast to L. major, induces the development of nonhealing lesions in B6 mice. (ii) Cells expressing IL-12p40, gamma interferon (IFN-gamma), NOS2, and CD40L are numerous in the footpad lesion and/or the draining popliteal lymph node of animals infected for up to 14 weeks with L. mexicana. (iii) B6 mice, either IL-12p40 deficient or treated with IL-12p40-neutralizing antibodies, display a dramatic enhancement of primary and secondary lesions leading to death 10 weeks after inoculation with L. mexicana. (iv) Splenocytes harvested 4 and 8 weeks after infection of IL-12p40(-/-) B6 mice with L. mexicana are unable to produce IFN-gamma, but secrete IL-4, IL-10, and IL-18. Thus, the early control of L. mexicana infection by B6 mice is independent of IL-12, whereas IL-12 and Th1 responses play a key role in controlling the late stages of L. mexicana infection. However, they fail to resolve lesions, in contrast to L. major infection, emphasizing the different outcomes induced by these two Leishmania species in B6 mice.
Laboratory of Parasitology, Free University of Brussels (ULB), Brussels, Belgium.
Fabiola
F
Aguilar Torrentera
Jon D
JD
Laman
Marjan
M
Van Meurs
Luciano
L
Adorini
Eric
E
Muraille
Y
Y
Carlier
D000818:Animals; D023201:CD40 Ligand / Q000378:metabolism; D005260:Female; D007371:Interferon-gamma / Q000378:metabolism; D018664:Interleukin-12 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D053762:Interleukin-12 Subunit p40; D020382:Interleukin-18 / Q000378:metabolism; D018320:Leishmania major / Q000472:pathogenicity; D007894:Leishmania mexicana / Q000472:pathogenicity; D016773:Leishmaniasis, Cutaneous / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009500:Neutralization Tests; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D021122:Protein Subunits; D013045:Species Specificity; D018418:Th2 Cells / Q000276:immunology; D013997:Time Factors
D053762:Interleukin-12 Subunit p40; D020382:Interleukin-18; D021122:Protein Subunits; D023201:CD40 Ligand; D018664:Interleukin-12; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse