Exploring Mycobacterium tuberculosis infection-induced alterations in gene expression in macrophage by microarray hybridization

Tuberculosis remains a serious threat to public health. Its causative agent Mycobacte- rium tuberculosis is an intracellular pathogen which survives and replicates within cells of the host immune system, primarily macrophages. Knowledge of the bacteria-macrophage interaction can help to develop novel measures to combat the disease. The global gene expression of macro- phage following invasion by and growth of M. tuberculosis was studied by cDNA microarray. Of the 12800 human genes analyzed, totally 473 (3.7%) macrophage genes were differentially expressed after being infected by M. tuberculosis, among which, only 25 (5.2%, corresponding to less than 0.2% of the 12800 genes) genes were up-regulated, while others (94.8%) were down-regulated against the control. Of the 473 genes, 376 genes are registered in the GenBank, and 97 are novel genes. Expression of 5 up-regulated genes has been induced by more than 3-fold. 25 genes were down-regulated by more than 3-fold. Syndecan binding protein has been down-regu- lated up to 12.5-fold. The data gave an insight into the early gene expression in macrophage ensuing M. tuberculosis infection and a basis for further study.