title: Susceptibility to Mycobacterium leprae of ALY (alymphoplasia) mice and IFN-gamma induction in the culture supernatant of spleen cells.
abstract: The aly/aly (alymphoplasia) mice from a mutation of a colony of the C57BL/6J mouse strain, which has a systemic absence of lymph nodes and Peyer's patches, are deficient in both T- and B-cell-mediated immune functions. We have undertaken a comparison of susceptibility to Mycobacterium leprae of ALY (aly/aly, aly/+) mice with C57BL/6J mice. The aly/aly mouse was found to have an excellent high susceptibility to M. leprae with no distinction between female and male. The aly/+ mouse also was more susceptible to M. leprae at an earlier stage than the C57BL/6J mouse. Therefore, we examined and compared the cytokine gene expression and gamma interferon (IFN-gamma) induction in the splenocytes of ALY mice. The expression of interleukin 4 (IL-4), IL-10 and IL-12 mRNA was weakly stimulated with ML-lysate in inoculated aly/aly mice but IL-2, IL-6, IGIF/IL-18 and IFN-gamma mRNA were not observed. None of the cytokine genes used appeared, except the mRNA for IL-1-alpha, when uninfected cultured spleen cells were stimulated with ML-lysate. Also, IFN-gamma production was not induced. However, the appearance of these cytokine genes was observed when stimulated with concanavalin A (ConA), and IFN-gamma production was also induced in the culture supernatant by aly/+ and even aly/aly mice stimulated with ConA. To examine the reason why IFN-gamma cannot be produced by splenocytes of ALY mice inoculated with M. leprae, we detected cytokine gene expression and IFN-gamma induction in the presence of recombinant murine IL-12 or IGIF/IL-18. IL-2 mRNA expression was detected in all of the mice tested in the presence of IL-12 but not in aly/aly mice under IGIF/IL-18, and iNOS mRNA expression was not observed in aly/aly mice under IL-12 or IGIF/IL-18. IL-4 and IL-10 mRNA were detected by aly/aly mice only by exposure to IGIF/IL-18. In culture, the supernatant with ML antigens of the aly/aly mice did not produce IFN-gamma in spite of the presence of IL-12 and IGIF/IL-18, while IFN-gamma was weakly induced in aly/+ mice stimulated with ML-lysate and in the presence of IGIF/IL-18. Nevertheless, IFN-gamma production was observed in splenocytes of the aly/aly mice stimulated with ConA and also with IGIF/IL-18 plus anti-CD3 antibody. Our results suggest that ALY mice might be showing a high susceptibility to M. leprae because of deficient priming for activation of T cells with the leprosy bacilli infection. Moreover, it is possible that the phagocytic activities of the macrophages of ALY mice are also impaired.
authors.affiliation: Leprosy Research Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yogi
authors.forename: M
authors.initials: M
authors.lastname: Endoh
authors.forename: T
authors.initials: T
authors.lastname: Banba
authors.forename: H
authors.initials: H
authors.lastname: Okamura
authors.forename: H
authors.initials: H
authors.lastname: Nomaguchi
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003470:Culture Media; D017931:DNA Primers / Q000737:chemistry; D004198:Disease Susceptibility; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D006651:Histocytochemistry; D007371:Interferon-gamma / Q000096:biosynthesis* / Q000235:genetics; D018664:Interleukin-12 / Q000235:genetics; D020382:Interleukin-18 / Q000235:genetics; D007918:Leprosy / Q000235:genetics / Q000276:immunology*; D008099:Liver / Q000166:cytology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009166:Mycobacterium leprae / Q000235:genetics / Q000276:immunology*; D012329:RNA, Bacterial / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012737:Sex Factors; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000166:cytology / Q000276:immunology* / Q000382:microbiology
chemical_list: D003470:Culture Media; D017931:DNA Primers; D020382:Interleukin-18; D012329:RNA, Bacterial; D012333:RNA, Messenger; D018664:Interleukin-12; D007371:Interferon-gamma