In this study experimental mouse model for Chlamydia pneumoniae
infection was used to elucidate the nature of immune response developing
during primary and secondary infection. First we examined the
mononuclear cells from different lymphoid organs in BALB/c mice during
C. pneumoniae infection and detected a strong lymphocyte influx into
mediastinal lymph nodes (MLN). To further characterize the C. pneumoniae
induced immune response the gene expression profiles of MLN derived
lymphocytes was studied. To identify genes characteristic for
reinfection we compared gene expression profiles during reinfection and
primary infection and found 148 genes to be differentially regulated in
CD19+ cells, 7 in CD4+ cells and 12 in CD8+ cells. A panel of these
genes was selected to be confirmed by real-time RT-PCR. Genes related to
interferon signaling like Ifit1, Ifit3, Gbp2, Irf7 and Usp18 were found
to be upregulated when reinfection was compared to primary infection.
In our study we were able to identify 8 genes that were differentially
expressed between reinfection and primary infection in lymphocytes.
These novel gene expression signatures provide new insights and clues to
the nature of protective immunity established during experimental C.
pneumoniae immunity.