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Andy (Qigui) Yu, M.D., Ph.D.

Associate Professor, Microbiology and Immunology

Summary of the focus of the research of Dr. Yu

Dr. Yu's laboratory mainly focuses on the immunopathology of HIV infection, and the clinical and immunological interactions between HIV and other human persistent viruses like HCV.

Description and summary of research focus of the laboratory

The reasons for the failure of the immune system to control HIV infection, and the resulting immunodeficiency, remain unclear. Infection with HIV is characterized by both continual virus replication and a vigorous immune response. Antibodies are elicited early in infection and are generally vigorous at all stages of HIV infection. However, these antibodies are unable to clear virus particles and infected cells by actions of the complement system, phagocytes or killer cells. Similarly, HIV infection is associated with an extremely vigorous virus-specific cytotoxic T-lymphocyte (CTL) response, but HIV disease ultimately progresses. Dr. Yu's laboratory is interested in understanding the molecular mechanisms by which HIV/HIV-infected cells provide resistance to antibody-dependent complement-mediated virotoxicity/cytotoxicity, and by which the continuous presence of the viral antigen(s) renders virus-specific T cells to become dysfunctional. The major areas of Dr. Yu's current research are: (1) Eradication of HIV reservoirs. We have investigated the abrogation of complement control protein function to facilitate HIV-specific antibodies in patient plasma to lyze the complement-resistant HIV virions. We are using this strategy to kill HIV-infected cells through complement-mediated cell lysis in order to eradicate HIV reservoirs. (2) Novel strategies to aid in vaccine design to enhance cellular immunity to persistent virus infection in immunocompromised hosts and aged individuals. We have incorporated the TNF superfamily molecules including CD40L, RANKL, and Ox40L, pivotal costimulatory molecules for immune responses, into poxvirus vectors in order to test their adjuvant activity in enhancing immunogenicity of poxvirus-based HIV vaccines. Co-immunization of regular mice with CD40L-expressing poxvirus and poxvirus-based HIV vaccines augmented HIV-1 specific CTL responses in terms of frequency, polyfunctionality and IL-7 receptor alpha chain expression. We are particularly interesting in exploring the adjuvant activity of these constructs in enhancing immunogenicity of HIV vaccines in CD4+ T cell-deficient or aged murine models. (3) Clinical and immunological interaction between HIV and HCV. We are interesting to investigate why HIV coinfection is associated with enhanced HCV replication, increased hepatic inflammation and fibrosis, and more rapid progression to cirrhosis and end-stage liver disease.

  •  Amet T., Ghabril M., Chalasani N., Byrd D., Hu N., Grantham A., Liu Z., Qin X., He JJ., Yu Q. CD59 incorporation protects hepatitis C virus from complement-mediated destruction. Hepatology. 2011 Sep 19. doi: 10.1002/hep.24686.PMID: 21932413
  • Chi X., Amet T., Byrd D., Shah K., Hu S, Grantham A., Duan J., Yu Q. Direct effects of HIV-1 Tat protein on excitability and survival of primary dorsal root ganglion neurons: possible contribution to HIV-1-associated pain. PLoS ONE, 2011, 6(9): e24412. PMCID: PMC3166319
  • Yu Q., Yu R., Qin X. The good and evil of complement activation in HIV-1 infection. Cell Mol Immunol. 2010, 7: 334 – 340. PMID: 20228834
  • Hu W., Yu Q., Hu N., Byrd D., Shikuma C., Shiramizu B., Halperin JA., Qin X. A high-affinity inhibitor of human CD59 enhances antibody-dependent complement-mediated virolysis of HIV-1. The Journal of Immunology, 2010; 184: 359–368. PMID: 19955519
  • Song Y., Zhuang Y., Zhai S., Huang D., Zhang Y., Kang W., Li X., Liu Q., Yu Q., Sun Y. Increased expression of TLR7 in CD8(+) T cells leads to TLR7-mediated activation and accessory cell-dependent IFN-gamma production in HIV type 1 infection. AIDS Res Hum Retroviruses. 2009 Dec;25(12):1287-95. PMID: 19954299
  • Hu N., Yu R., Shikuma C., Shiramizu B., Ostrowski, MA., Yu Q. Role of cell signaling in poxvirus-mediated foreign gene expression in mammalian cells. Vaccine. 2009; 27 (22):2994-3006. PMID: 19428911
  • Yu Q., Hu N., Ostrowski MA. Poxvirus tropism for primary human leukocytes and hematopoietic cells. Methods Mol Biol.2009; 515:1-20. PMID: 19378122
  • Liu J., Yu Q., Stone GW., Yue FY., Ngai N., Jones RB., Kornbluth RS., Ostrowski MA. CD40L expressed from the canarypox vector, ALVAC, can boost immunogenicity of HIV-1 canarypox vaccine in mice and enhance the in vitro expansion of viral specific CD8(+) T cell memory responses from HIV-1-infected and HIV-1-uninfected individuals. Vaccine. 2008 Jul 29;26(32):4062-72. PMID: 18562053
  • Yu Q., Yue FY., Gu XX., Schwartz H., Kovacs CM., Ostrowski MA. OX40 ligation of CD4+ T cells enhances virus-specific CD8+ T cell memory responses independently of IL-2 and CD4+ T regulatory cell inhibition. The Journal of Immunology. 2006; 176(4): 2486-95. PMID: 16456009
  • Yu Q., Jones B., Hu N., Chang H., Ahmad S., Liu J., Parrington M., Yewdell J., Ostrowski MA. Comparative analysis of tropism between Canarypox (ALVAC) and Vaccinia viruses reveals a more restricted and preferential tropism of ALVAC for human cells of the monocytic lineage. Vaccine. 2006; 24(40-41):6376-91. PMID: 16859816
  • Ostrowski MA., Yu Q., Yue FY., Liu J., Jones B., Gu XX., Loutfy M., Kovacs CM., Halpenny R. Why can't the immune system control HIV-1? Defining HIV-1-specific CD4+ T cell immunity in order to develop strategies to enhance viral immunity. Immunol Res. 2006; 35(1-2): 89-102. PMID 17003512
  • Yu Q., Chow E., Wong H., Gu J., Mandelboim O., Gray-Owen S., Ostrowski MA. CEACAM1 (CD66A) promotes human monocyte survival via a phosphatidylinositol 3-kinase and AKT-dependent pathway. J Biol Chem. 2006 Dec 22;281(51):39179-93. PMID: 17071610
  • Yu Q., Gu JX., Kovacs C., Freedman J., Thomas EK., Ostrowski MA. Cooperation of TNF Family Members CD40 Ligand, Receptor Activator of NF-kappaB Ligand, and TNF-alpha in the Activation of Dendritic Cells and the Expansion of Viral Specific CD8(+) T Cell Memory Responses in HIV-1-Infected and HIV-1-Uninfected Individuals. The Journal of Immunology. 2003; 170(4):1797-1805. PMID: 12574344
  • Yu Q., Kovacs C., Yue FY., Ostrowski MA. The Role of the p38 MAPK, ERK, and PI3K Signal Transduction Pathways in CD40L induced Dendritic Cell Activation and Expansion of Virus Specific CD8+ T Cell Memory Responses. The Journal of Immunology. 2004; 172(10): 6047-6056. PMID: 15128788

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  • M.D. 1986: Wannan Medical College, China
  • M.S.  1989: Fourth Military Medical University, China
  • Ph.D. 1995: Fourth Military Medical University, China
  • Post doctoral, 1997 - 2001: University of Hawaii School of Medicine, Honolulu, Hawaii
  • Post doctoral, 2001 - 2005: University of Toronto, Toronto, Canada

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