Baylor Institute for Immunology Research (BIIR): Abstracts and Video Presentations from the Second Annual Baylor Symposium and Workshop on Human Immunology and Biodefense, October 30-31, 2005

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Second Annual Baylor Symposium and Workshop on Human Immunology and Biodefense, October 30-31, 2005: Abstracts

Videos from the Symposium are available for you to watch online.

	Module 1: Welcome Karolina Palucka, MD, PhD - Baylor Institute of Immunology Research and Ira Mellman, PhD - Yale University School of Medicine Video in MOV format: 2:21 minutes, 3.94 MB Video in WMX format: 2:21 minutes, 4.14 MB
	Module 2: Human DCs and Responses to HIV and EBV Ralph Steinman, MD - The Rockerfeller University Video in MOV format: 44:06 minutes, 73.60 MB Video in WMX format: 44:06 minutes, 79.36 MB
	Module 3: Interaction of Influenza Virus with Human DC Subsets Karolina Palucka, MD, PhD - Baylor Institute of Immunology Research Video in MOV format: 26:48 minutes, 71.47 MB Video in WMX format: 26:48 minutes, 72.20 MB
	Module 4: Plasmacytoid DCs and Pathogens Yong-Jun Liu, MD, PhD - M.D. Anderson Cancer Center Video in MOV format: 44:46 minutes, 58.24 MB Video in WMX format: 44:46 minutes, 63.26 MB
	Module 5: DC-SIGN as a Pathogen Anchor on DCs Yvette van Kooyk, PhD - VU University Medical Center Video in MOV format: 44:46 minutes, 62.63 MB Video in WMX format: 44:46 minutes, 63.84 MB
	Module 6: Cell Biology of DCs Exposed to Pathogens Ira Mellman, PhD - Yale University School of Medicine Video in MOV format: 53:29 minutes, 94.04 MB Video in WMX format: 53:29 minutes, 96.10 MB
	Module 7: Superantigen Toxins Raymond Kaempfer, PhD - The Hebrew University of Jerusalem Video in MOV format: 45:02 minutes, 79.22 MB Video in WMX format: 45:02 minutes, 80.81 MB
	Module 8: CpG Oligos to Protect Against Class A Pathogens Arthur Krieg, MD - Coley Pharmaceutical Group Video in MOV format: 45:50 minutes, 82.52 MB Video in WMX format: 45:50 minutes, 82.29 MB
	Module 9: Humanized Mice to Study Human-Specific Enteric Pathogens Samuel Stanley, MD - Washington University School of Medicine Midwest Regional Center of Excellence for Biodefense and Emerging Disease Research Video in MOV format: 39:05 minutes, 70.71 MB Video in WMX format: 39:05 minutes, 70.04 MB
	Module 10: Anthrax Toxins John Collier, PhD - Harvard Medical School Video in MOV format: 57:51 minutes, 90.67 MB Video in WMX format: 57:51 minutes, 103.99 MB
	Module 11: Characterization of the Humoral Immune Response to Bacillus anthracis Sherry Crowe, PhD - Oklahoma Medical Research Foundation Abstract Video in MOV format: 44:04 minutes, 28.50 MB Video in WMX format: 44:04 minutes, 35.15 MB
	Module 12: Cowpox Virus Inhibits Primary Immune Function of Monocyte Derived Spencer Hansen - University of New Mexico Health Science Center Abstract Video in MOV format: 16:58 minutes, 30.49 MB Video in WMX format: 16:58 minutes, 30.37 MB
	Module 13: Effects of Anthrax Toxin on Murine Dendritic Cells Nuria Reig, PhD - University of Geneva Abstract Video in MOV format: 21:24 minutes, 31.14 MB Video in WMX format: 21:24 minutes, 38.15 MB
	Module 14: Introduction Humanized Mice Francesca Macchiarini, PhD - National Institute of Allergy and Infectious Diseases Video in MOV format: 17:00 minutes, 30.69 MB Video in WMX format: 17:00 minutes, 30.44 MB
	Module 15: Modeling of Human T Cell Immunity In Vivo in Humouse Caroline Aspord, PhD - Baylor Institute of Immunology Research Abstract Video in MOV format: 20:56 minutes, 35.27 MB Video in WMX format: 20:56 minutes, 37.58 MB
	Module 16: In Vivo Model of Influenza Virus Infection in Humouse Chun I. Yu - Baylor Institute of Immunology Research Baylor University Abstract Video in MOV format: 17:36 minutes, 31.17 MB Video in WMX format: 17:36 minutes, 31.58 MB

Abstracts from the Symposium

Generation of Human T Cell Immunity In Vivo in Humouse Caroline Aspord, Mike Gallegos, Florentina Marches, Sasha Tindle, Jacques Banchereau, & A. Karolina Palucka. Baylor Institute for Immunology Research, Dallas, TX

The generation of a functional adaptive human immune response in Humouse has been a challenge. We used the Humouse bearing human tumor cells to assess the generation of a tumor specific immune response. Human breast tumor and melanoma mobilized human dendritic cells to the tumor site and draining lymph nodes. Adoptive CD8 T cell transfer led to breast tumor regression. Upon both intratumoral and intravenous T cell transfer, CD8 T cells purified from the tumor site exhibited ex vivo CTL activity. In addition, the development of anti-tumor CD8 T cell response required the presence of DC, suggesting an indirect antigen presentation pathway. In contrast to melanoma, the cotransfer of CD4 T cells led to accelerated breast tumor development. This effect is mediated through the generation of proinflammatory CD4 T cells secreting IL4, IL5, IL13 and TNF?. Altogether we showed the production of functional CD4 and CD8 T cell immune responses elicited towards breast tumor in Humouse. Thus, Humouse is a valuable model to study the development and modulation of tumor immunity.

Characterization of the Humoral Immune Response to Bacillus anthracis
Sherry R. Crowe, Timothy F. Gross, & Judith A. James. Oklahoma Medical Research Foundation, Oklahoma Health Sciences Center, Oklahoma City, OK

The causative agent of anthrax, Bacillus anthracis, is a spore-forming bacterium found naturally in the soil that causes cutaneous infection; however, recent events have focused interest on the threat posed by inhalation anthrax infection. The current anthrax vaccine requires six primary vaccinations, annual boosters, and has been associated with serious adverse events. Improved understanding of the immune response to this infectious agent would allow refined vaccine development with potentially fewer adverse events. This study seeks to identify the major humoral epitope targets of B. anthracis. To accomplish this goal, we obtained sera from anthrax vaccinated individuals and matched controls. Antibodies to protective antigen and lethal factor were measured. As expected, all vaccinated individuals had anti-protective antigen antibodies, while only a subset had detectable anti-lethal factor antibodies. No correlations between the number of vaccinations, length of time since last vaccine, or adverse events were detected with the magnitude of the antibody response. Overlapping decapeptides synthesized on polyethylene solid phase supports (779 peptides) were tested to identify common antigenic regions within the sera of these vaccinated individuals. Two major, common antigenic regions are detected by anti-lethal factor positive sera. The protective antigen response could be divided based upon antibody levels into high responders, medium responder, and low responders. When examining the anti-protective antigen response, we found one common antigenic region within the high responders, four common regions within the medium responders, and two common regions within the low responders. These preliminary findings from these humoral epitope-binding studies have important implications for vaccine design and immunotherapeutic development.

Cowpox Virus Inhibits Primary Immune Function of Monocyte Derived Dendritic Cells In Vitro
S. J. Hansen1, G. K. Olson1, C. R. Lyons2, M. F. Lipscomb1. Departments of 1Pathology and 2Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM

The primary function of dendritic cells (DCs) is to survey their environment for microbes, viruses, or parasites. Once they encounter such invaders, DCs phagocytose them; migrate to regional lymph nodes and present processed antigen (Ag) to naïve T cells promoting clonal expansion. Variola virus (smallpox) is a Category-A biothreat that is readily transmitted resulting in high mortality in humans. Infection occurs via inhalation, making aerosolization an effective way to initiate a primary infection. In this scenario pulmonary DCs would be one of the first cell types to encounter the virus. Therefore, it is important to understand the interactions of Orthopoxviruses, (i.e. variola, vaccinia, Cowpox) with DCs as they all share the ability to subvert the human immune system. We incubated monocyte derived dendritic cells (MDDCs) with Cowpox virus (CPXV), a surrogate for smallpox, to determine how the virus might affect the antigen-presenting function of these cells. MDDCs were treated for 24 hours with media, LPS, CPXV, or a combination of CPXV and LPS. Analysis of MDDCs by light microscopy showed that treatment with CPXV induced the formation of multinucleate syncytia, cytoplasmic vesicles, and membrane blebbing compared to untreated MDDCs. CPXV treatment did not induce cytokine release from MDDCs but rather prevented the typical cytokine response of MDDCs responding to lippolysaccharide (LPS). Following exposure to CPXV, MDDCs had no capacity to promote CD4+ T cell proliferation in a mixed leukocyte reaction (MLR) despite the fact that the MDDCs retained their viability determined by trypan blue exclusion and Tunel assay. FACS analysis indicated that the costimulatory molecules CD80 and CD86 were expressed at lower levels in CPXV treated MDDCs as compared to untreated cells. Following treatment with CPXV, administration of LPS was unable to restore expression of the costimulatory molecules. Taken together these studies indicate that CPXV and, therefore, likely other members of the family Orthopoxvirdae inhibit the ability of DCs to stimulate an allogeneic T cell proliferative response, potentially by inhibiting both DC cytokine secretion and co-stimulatory molecule expression.

Effects of Anthrax Toxin on Murine Dendritic Cells
Nuria Reig, Stephen Leppla, Richard Flavell, Ira Mellman & Gisou van der Goot. Department Microbiology and Molecular Medicine, C.M.U. University of Geneva, Geneva, Switzerland.

Anthrax toxin is an AB type toxin, with a B subunit involved in cell surface binding, endocytosis and cytoplasm translocation of the A subunit which bears the toxic enzymatic activity. Bacillus anthracis uses an immune evasion strategy that involves the impairment several cells of the immune system, like macrophages, T cells and dendritic cells. We found that anthrax lethal toxin causes death to mouse dendritic cells in their immature state but not in their mature state, although the binding and entry of the toxin is similar in both situations. Moreover, the susceptibility of mouse DCs to be killed by the toxin depends on mouse strain, showing correlation with the macrophage phenotype. As dendritic cells play a pivotal role in regulating immune responses, killing them appears to be one strategy of the bacteria to disarm the immune defences of the host, ensuring the progression of the infection.

In Vivo Model of Influenza Virus Infection
Chun I. Yu, Florentina Marches, Mike Gallegos, Jacques Banchereau and A. Karolina Palucka. Baylor Institute for Immunology Research, Dallas, TX

The Humouse model is being used to study the in vivo immune response induced by dendritic cells (DCs) upon influenza virus infection. Beta2-microglobulin-deficient NOD/SCID mice are transplanted with human haematopoietic stem cells. Approximately 4 to 6 weeks post transplantation there are distinct DC subsets: myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) in the blood and Langerhans cell in peripheral tissue. We have analyzed the composition of human antigen presentation cells in the lung of Humice with and without exposure to influenza virus. We have found the presence of mDCs, pDCs and monocytes that are considered precursor of mDCs. Upon viral exposure, we observed accumulation and activation of all of these subsets. Furthermore, intranasal infection led to enhanced transcription of human type I interferon. Finally, our preliminary data suggests generation of specific IgG. This in vivo model of viral infection could be useful in studying different strains of influenza virus and testing potential vaccines.