The Comparative Study Of The Different Gene Expression In PBMC From Healthy Individuals And Tuberculosis Patients

Background: Tuberculosis has the tendency to revive and about 1/3 of the people in the world have already been infected, but most people will not become a tuberculosis patients during their life, only about 10% of the persons will develop into the tuberculosis patients . It is obvious that the individual difference has existed in the morbidity of tuberculosis, and the inherent factors acts on a crucial role.There is high disease variability with the dizygotic twins than monozygotic twins,and infection rates differ among racial groups . Moreover, the emergence, development and transferring of the bacteria in host not only due to its virulence and quantity , also depend on the immune state of the host. So,It is emergence to pay attention to host hereditary that effect to the developing of tuberculosis.Tuberculosis is a kind of intracellular bacteria that can grow in macrophage, the clearance of the tuberculosis depends on TH1/TH2 cell's equilibrium of factors. that is to say, the state of emergence, development, transfer and developing of chronic delays of tuberculosis is the result of the inversion of TH1 and TH2 regulated by cytokines.So gene expression study of peripheral blood mononuclear cells (PBMC) from tuberculosis patients can contribute to understand the molecular mechanism of tuberculosis infection, development and transfer. Further more it can provide the essential basic data which is useful for the development of new vaccine of tuberculosis, diagnosis chip for early infection, diagnosis and new medicine discovery as. So it can getting more essential data to compares the expression table of PBMC from tuberculosis patient, PPD positive and PPD negative volunteers healthy. Use the whole gene chip of people, cDNA of genome, compare difference of gene expression of PBMC in patients and healthy volunteers , in order to investigate the molecule mechanism of the host immunity to tuberculosis.Method: Choose 4 tuberculosis patients, 4 PPD positive and 4 negative volunteer 4 respectively. Collect the peripheral blood 12ml and extract the PBMC, after culturing in the incubator for 6-8 hours, use by purified ESAT-6/CFP - 10 merge proten stimulating for 17-20 hours; Extract RNA of PBMC after stimulating, reverse transfer into cDNA, hybridizes in the human whole genome cDNA chip, read the data. Compare results of the three groups. Obtain the different expression gene.Result: After check and compare the chips of 4 sample of every groups, we found the different expression gene between PPD positive and tuberculosis patient; PPD negative and PPD positive; PPD positive, PPD negative and tuberculosis patient. so we can make three group analysis data of difference gene of expression. Every group select the gene that P< 0.05, the multiple> 2 times. compared with PPD negative and PPD positive expression difference have 709, 295 is down and 414 is up. Among them there are 68 known genes related to immunity, there are 8 relevant with cells killing. Make comparisons to PPD positive and tuberculosis patient, as P value< 0.05,the multiple> 2 times,the difference express gene have 1604, 544 is down and 1060 is up. Among them there are 91 known genes related to immunity, there are 9 genes related to cells killing . PPD positive, PPD negative and tuberculosis patient make comparisons, as P value < 0.05, the multiple> 2 times, there are 157 express difference genes, among them compare between PPD positive and tuberculosis patient, there are 72 genes reduced, the gene raised has 85. PPD positive and PPD negative between compare,it is 74 genes reduced, the gene raised has 83. There are 19 related to immunity in 157 genes. there are 5 genes related to cell killing.Assign to one more layer of difference gene among them, reveal the gene expression difference related to immunity is prominent. It is easy to be known and relevant (IL-12B, IFNG, TNF, PTPRC, IL-10, NRAMP1) that they are obvious difference gene in tuberculosis. some encode and regulate important factor about cell immune (IL-12B, IL-10, IL-2,etc.), some other genes have not found relation to tuberculosis so far.Conclusion: The differences expressing genes between PPD positive, PPD negative healthy volunteers and tuberculosis are more prominent in those associated with immune system genes; and these immune-related gene, many with TB susceptibility, shows tuberculosis susceptibility genes is key gene of the host to defense against and kill Mycobacterium tuberculosis .