title: Interleukin-4 but not gamma interferon production correlates with the severity of murine cutaneous leishmaniasis.
abstract: For murine cutaneous leishmaniasis, data to date suggest a correlation between the presence of gamma interferon (IFN-gamma) and resistance in C57BL/6 mice and the presence of interleukin-4 (IL-4) and disease in BALB/c mice. In this study, 13 inbred strains of mice covering the range of susceptibility to disease were infected with Leishmania major to determine whether the subsequent expression of IFN-gamma or IL-4 is a reliable indicator of cure or progressive disease. The presence of IL-4 and IFN-gamma mRNAs in the draining lymph nodes was examined 9 weeks after infection, when differences in disease severity became obvious. There were large differences in the levels of IL-4 mRNA among the different strains, whereas IFN-gamma mRNA was detected at similar levels in all strains. The levels of IL-4 mRNA correlated with lesion score, with susceptible and intermediate strains containing up to 100-fold more than any of the resistant strains. Differences in the levels of IFN-gamma mRNA were within only a fourfold range, with significant overlap among susceptible, intermediate, and resistant strains. Similarly, the levels of IFN-gamma secreted in vitro by lymph node cells from infected mice in response to L. major antigens were within a 10-fold range for most strains, and there was no correlation with lesion score. Analysis of Leishmania-specific antibody levels revealed a correlation between immunoglobulin G1 (IgG1) titers and lesion score, consistent with the role of IL-4 as a switch factor for IgG1. In contrast, there was no correlation between IgG2a titers and lesion score, supporting the notion that IFN-gamma synthesis (which promotes IgG2a production) is not correlated with disease state. These data suggest that along the spectrum of murine cutaneous leishmaniasis, IL-4 is a reliable indicator of disease, but IFN-gamma is not prognostic for resistance.
authors.affiliation: Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Morris
authors.forename: A B
authors.initials: AB
authors.lastname: Troutt
authors.forename: K S
authors.initials: KS
authors.lastname: McLeod
authors.forename: A
authors.initials: A
authors.lastname: Kelso
authors.forename: E
authors.initials: E
authors.lastname: Handman
authors.forename: T
authors.initials: T
authors.lastname: Aebischer
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D001483:Base Sequence; D005260:Female; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000235:genetics; D015847:Interleukin-4 / Q000096:biosynthesis* / Q000235:genetics; D007895:Leishmania tropica / Q000276:immunology; D016773:Leishmaniasis, Cutaneous / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D000913:Antibodies, Protozoan; D012333:RNA, Messenger; D015847:Interleukin-4; D007371:Interferon-gamma