|Hui Xu, Ph.D.|
University of Alabama at Birmingham
The major research interest of Dr. Xu's laboratory is to investigate regulatory mechanisms for immune responses in inflammatory diseases and tumors. Immune regulation or feedback regulation after activation of the immune system is a crucial mechanism for balancing the level of immune responses and preventing diseases caused by overreaction. The study is of special importance since in many of clinical immune-related disorders, the immune system in patients has been already activated. Understanding of the regulatory mechanism will not only provide clues to pathogenesis of immune-related disorders but may also be exploited to develop new strategies for treatment. Currently, Dr. Xu is focusing on two main projects.
PD-1 and PD-1 ligands. PD-1 is expressed by activated T cells and plays important regulatory roles in immune responses. So far, two ligand molecules for PD-1, B7-H1 and B7-DC, have been identified. Although PD-1 appears to provide negative signals for T cells, the function of its two ligands is controversial. Dr. Xu is investigating the role of B7-H1 in the regulation of immune responses by dendritic cells and as well as by non-antigen presenting cells. The long-term goal is to determine whether targeting PD-1 mediated immunosuppression provides a therapeutic potentials for autoimmune and inflammatory diseases, graft rejection, and tumors.
Slits and Robos. Slits are neuronal repellents and Robos are the transmembrane receptors for Slits, which both are expressed mainly in the brain. The molecules play important roles in axon guidance and the development of the nervous system. However, the role of Slits/Robos in the regulation of immune responses and inflammatory reactions is unexplored. Dr. Xu has two interrelated projects investigating whether Slits are anti-inflammatory factors in the regulation of immune responses and whether they are involved in tumor mediated immunosuppression.
Xu H., Bjarnason B., and Elmets C.A. Sensitization vs. elicitation in allergic contact dermatitis: potential differences at cellular and molecular levels. American J Contact Dermatitis. 11:228-234, 2000.
Barlow SC, Xu H, Weaver C.T., Lindsey J.R., Schoeb T.R., and Bullard D.C. Development of dermatitis in CD18-deficient PL/J mice is not dependent on bacterial flora, and requires both CD4+ and CD8+ T lymphocytes. International Immunol. 16:345-351, 2004.
Huang C-M, Xu H., Wang C.C., and Elmets, C.A.. Proteomic characterization of skin and epidermis in response to environmental agents. Expert Review of Proteomics. 2:808-820, 2005.
Hee K.K., Hongbing G., Guorui Z., Hui L., Xu F., and Xu H. High level expression of B7-H1 molecules by dendritic cells suppresses the function of activated T cells and desensitizes primed animals. J Leukoc Biol. 76:686-695, 2006.
He D., Wu L., Kyung K.H., Li H., Li H., Elmets C.A., and Xu H. CD8+ IL-17 producing T cells are important in effector functions for the elicitation of contact hypersensitivity responses. J. Immunol. 177:6852-6858, 2006.
Yusuf N., Timares L., Seibert M.D., Xu H., and Elmets C.A. Acquired and innate immunity to polyaromatic hyrdrocarbons. Toxicol Appl Pharmacol. 224: 308-312, 2007.
Hsu H-C, Yang P.A., Wu Q., Myers R., Wang J., Guentert T., Chen J., Yi J., Tousson A., Stanus A., Le T.L., Lorenz R.G., Xu Hu., , Kolls J.K., Carter R.H., Chaplin D.D., Willilams R.W. and Mountz J.D. Interleukin17-producing T helper cells and interleukin 17 orchestrate autoreactive germincal center development in autoimmune BXD2 mice. Nat Immunol. 9: 166-65, 2008
Nasti T., Long A., Naseemuddin M., Lucas A., Xu H., and Elmets, C.A. Protective role of TLR4 during the initiation stage of cutaneous chemical carcinogenesis TLR4 in cutaneous DMBA carcinogenesis. Cancer Research. 15: 615-22, 2008
National Institutes of Health
National Institutes of Health