Differential expression of ferritin heavy chain in THP-1 cells infected with Mycobacterium bovis BCG.

To identify the host genes induced or suppressed by infection of mycobacteria, the reverse transcriptase polymerase chain reaction (RT-PCR) and the differential display reverse transcriptase polymerase chain reaction (DD RT-PCR) methods were used. In this study, cDNAs complement to mRNA extracted from human peripheral monocyte derived naive THP-1 cells, THP-1 cells infected with live Mycobacterium bovis BCG, THP-1 cells treated with heat-killed BCG, and THP-1 cells incubated with IgG-coated glass-beads were compared on the sequencing gel. One (TG2-1) of the clones selected by DD RT-PCR is 446 bp long and is identical to human ferritin heavy (H) chain gene. Northern blot analysis confirmed that ferritin H chain gene has been markedly over-expressed in monocytic THP-1 cells incubated with live and dead M. bovis BCG. Differential display techniques of host genes whose expression levels were varied by infection of mycobacteria could provide information about the response of macrophages to mycobacterial infection.