ANALYSIS OF CYTOKINE MESSENGER-RNA EXPRESSION IN LISTERIA-RESISTANT C57BL 6 AND LISTERIA-SUSCEPTIBLE A/J MICE DURING LISTERIA-MONOCYTOGENESINFECTION/

This laboratory previously reported than mRNA expression for many cyto kines, as determined by reverse transcription-polymerase chain reactio n analysis, is induced rapidly in the spleen during murine listeriosis . In the present study, the patterns of cytokine mRNA expression in sp leens and livers of Listeria-resistant C57BL/6 and Listeria-susceptibl e A/J mice were compared. In addition, in situ hybridization was perfo rmed to evaluate the distributions of cytokine mRNA-expressing cells i n these tissues. Listeria-resistant C57BL/6 mice demonstrated greater expression of gamma interferon (IFN-gamma) and granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNAs in the spleen than Listeria-s usceptible A/J mice. Greater numbers of cells expressing IFN-gamma and GM-CSF mRNAs were observed by in situ hybridization in the spleens of C57BL/6 mice than in those of A/J mice. C57BL/6 and A/J mice did not differ in their expression of IFN-gamma mRNA in the liver. Nor did C57 BL/6 and A/J mice differ in their expression of tumor necrosis factor alpha, interleukin-1alpha (IL-1alpha), IL-2, IL-4, or IL-6 mRNA in the liver or spleen, as determined by reverse transcription-polymerase ch ain reaction and in situ hybridization. These results indicate that th e greater resistance of C57BL/6 mice to Listeria monocytogenes infecti on is associated with greater expression of IFN-gamma and GM-CSF mRNAs in the spleen and GM-CSF mRNA in the liver.