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C. David  Pauza

C. David Pauza Ph.D.

Academic Title: Professor
Primary Appointment: Medicine
Secondary Appointments: Microbiology and Immunology
Location: 725 W. Lombard Street, N546
Phone: (410) 706-1367
Fax: (410) 706-6212
Lab: (410) 706-1365

Personal History:

Dr. Pauza received the PhD in 1981 from the University of California, Berkeley. From 1981-1985, Dr. Pauza was a postdoctoral fellow and staff member of the Laboratory of Molecular Biology at the Medical Research Council, Cambridge, England. In 1985 Dr. Pauza moved to the Salk Institute for Biological Studies in La Jolla, California where he started the AIDS Research Program and guided its development until 1990 when he accepted an appointment at the University of Wisconsin-Madison. Dr. Pauza created the Immunology and Virology Division at the Wisconsin National Primate Center and established strong interdisciplinary programs in AIDS involving basic, clinical, and animal models research. After 10 years at the University of Wisconsin, Dr. Pauza moved to the Institute of Human Virology as Professor in the Basic Science Division and (since 2004) Assistant Director. Dr. Pauza is also appointed as Professor (tenure) in the Department of Medicine and Adjunct Professor, Department of Microbiology and Immunology. In addition to 25 years in laboratory, animal model and clinical studies on HIV/AIDS, Dr. Pauza has an active program in tumor immunology with efforts to pioneer new approaches for clinical management of disease through immunotherapy. Dr. Pauza is engaged in promoting international biomedical research. He is a consultant in immunology for the Chinese Integrated Program on AIDS (CIPRA) and a member of the Scientific Board for the Chantal Biya Center for International Research in Yaounde, Cameroon. He serves on the Southwest Biomedical Foundation National Primate Center Advisory Board. Dr. Pauza has authored over 160 original monographs and is actively funded by the National Institutes of Health, USA and by the Gates Foundation. His laboratory pursues four main goals: 1) Understand the roles for gamma/delta T cells in human viral disease and cancer. 2) Explore the contacts between mother and fetus and learn how infectious diseases in the mother can remodel fetal immunity. 3) Define the mechanisms of HIV pathogenesis with particular attention to acute infection and depletion of uninfected cells. 4) Development and testing of preventive vaccines against HIV.

Since 1984 Dr. Pauza has been committed to basic research and education in support of the fight against AIDS. He continues this work at the Institute of Human Virology, by developing domestic and international programs to address fundamental challenges to the prevention and treatment of HIV/AIDS and new approaches to cancer therapy.

Research Interests:

A subset of lymphocytes, designated γδ T cells for the presence of their unusual T cell receptor, are part of the response to infectious disease and cancer. A specific sub-population expressing the Vγ2Vδ2 T cell receptor, is deleted in persons with progressing HIV infection and is only partly recovered after long-term therapy. The mechanism for cell depletion is unknown, but does not involved direct infection by HIV since these cells lack the CD4 primary receptor for virus. Because γδ T cells are implicated in both infectious diseases and cancer, we are encouraged to understand their regulation and effector functions in order to find novel mechanisms that link increased risk of malignant disease to HIV infection. As part of the Viral Oncology Program, studies focus on the natural history of γδ T cells in HIV infection and cancer, while seeking new approaches for therapeutic intervention in these disease processes.

1) Regulation of Vγ2Vδ2 T cell cytotoxicity: We discovered recently that CD56 expression identifies a subset of Vγ2Vδ2 T cells with potent cytotoxicity for human tumor cell lines. In HIV disease, the CD56+ subset is quantitatively depleted of Vγ2Vδ2 T cells, and there is a corresponding loss of CD56+ NK cell subsets. We believe the mechanisms for loss of CD56+ cells and eventually for the depletion of all Vγ2Vδ2 T cells, are linked. Laboratory studies defined a molecular interaction between γδ T cells and NK cells that might explain the coordinate regulation of these subsets. The phosphoantigen-reactive Vγ2Vδ2 T cells secrete high levels of IFN-γ and express the costimulatory molecule 4-1BBL after stimulation in vitro. When Vγ2Vδ2 T cells are depleted from PBMC that are stimulated subsequently with IgG1 and IL2, NK cell activation is far below expected levels. When Vγ2Vδ2 T cells are added back, NK cells are activated, express CD56/NKG2D, show increased levels of 4-1BB receptor and become potently cytotoxic. The requirement for Vγ2Vδ2 T cells is substituted partly by P815 cells that were transfected to express human 4-1BBL.

These data, combined with our recent work on TNF receptors on Vγ2Vδ2 T cells, are beginning to produce a model for cell activation and homeostatic regulation. We know that CD56+ cells of all types are modulated during HIV disease; the Vγ2Vδ2 T cells and NK cells comprise the bulk of cells that express CD56 in healthy individuals. Now we have evidence for cross-talk among γδ T cells and NK cells, operating through the 4-1BB costimulatory receptor and possibly involving cytokines such as IFN-γ. We have not yet tested for a reciprocal regulation wherein NK cells signal γδ T cells, and that is clearly a possibility.

These data raise intriguing questions about the regulation of â?ounconventionalâ? lymphocytes and how they are impacted by HIV disease. There are sparse but consistent data indicating that Vγ2Vδ2 T cells are depleted early in HIV disease and we know from a few labs, that NK cells are also altered, although not quantitatively depleted. During HIV disease, NK cells accumulate in an unusual CD56-/Siglec7-/CD16+ subset that is incapable of cytotoxicity against tumor cell targets. With durable control of viremia, NK subsets gradually regain the normal composition where approximately 50% of cells are CD56+/Siglec-7+/CD16+, the phenotype of potent effectors (Brunetta, at al, Blood 2009). The extent to which Vγ2Vδ2 T cell depletion affects the changes in NK cells and whether both populations recover together is not known.

A linkage between NK and γδ T cells seems likely as these cells share expression of NK receptors and KIR, they both have high frequency of CD56 expression and both are capable of MHC-unrestricted recognition of target cells. Much of our current work is to uncover the signal transduction pathways that make γδ T cells unique, and to understand the mechanisms controlling homeostasis in this unusual subset of T cells.

2) Exploiting γδ T cells for enhanced ADCC in HIV disease and cancer: Cytotoxic Vγ2Vδ2 T cells (CD56+) also express FcRγIIIa (CD16) the surface receptor for IgG1. In recent studies, we showed that activated Vγ2Vδ2 T cells are strong effectors of antibody-dependent cellular cytotoxicity against tumor cells and target cells decorated with HIV Env protein. In tumor cell studies, we incubated Vγ2Vδ2 T cells with TU167 (squamous cell carcinoma head and neck, SCCHN) in the presence or absence of Cetuximab (anti-EGFR) that is used for clinical therapy of recurrent/metastatic SCCHN. The addition of specific targeting antibody increased the efficiency of tumor cell killing more than twice. A similar result was obtained when Vγ2Vδ2 T cells were used to kill CCR5+ CEM T cells that were decorated with Env glycoprotein, then exposed to anti-Env antibody and then incubated with effector cells. The target cell line in this assay, CEM.NKR, is highly resistant to γδ T cell killing. When soluble Env protein was bound to the cell surface and Env-specific monoclonal antibodies were added, we observed >30% specific lysis at an effector to target cell ratio of 25 compared to a background killing of <2%. In these two assays, Cetuximab targeted killing of SCCHN tumor cells and anti-Env targeted killing of cells decorated with Env protein, activated γδ T cells were potent effectors of ADCC.

We are applying this knowledge to two diseases: squamous cell carcinoma head and neck (SCCHN) & HIV. In the first example, we have proposed a Phase I clinical trial of zoledronic acid/IL2 (γδ T cell stimulating conditions) in patients receiving Cetuximab for recurrent/metastatic Stage IVb head and neck cancer. The rationale are that patients with this diagnosis have a short life expectancy (5.4 months in the absence of therapy) that is extended to 8.7 months with Cetuximab and this provides an convenient setting for testing adjunctive approaches that might improve the objective responses; Cetuximab is used as a single agent so we avoid complications of concurrent cytoreductive therapy or radiation; we have sufficient numbers of patients each year (~70) with this diagnosis so we can complete clinical trials in a reasonable time. Our proposed protocol has first level approval from Novartis Corp. to support the dug costs. The protocol involves two rounds of γδ T cell stimulation with concurrent Cetuximab at the standard of care. This approach might be applied to cancer of viral origin, especially if they express viral proteins on the cell surface.

The second potential application for enhanced ADCC is to reduce SHIV viremia in infected macaques. We know that SHIV+ animals sustain more than 50% of starting levels for γδ T cells and have strong responses to zoledronic acid/IL2. We propose to inject SHIV+ macaques with a cocktail of monoclonal antibodies that have documented capacity for ADCC against Env-decorated targets. Concurrently, we will stimulate γδ T cells with intravenous zoledronic acid/IL2. We measure the decline in viremia and test for greater therapeutic effect in the enhanced ADCC animals. Beyond conventional therapy, we would like to explore enhanced ADCC as an approach for eliminating the viral reservoir. Conceptually, there are similarities between the need for quantitative elimination of metastatic cancer cells and quantitative depletion of the viral reservoir. In cancer, we use targeting antibodies designed to be selective for neoplastic cells. During viral infection, we can use monoclonal antibodies against viral membrane glycoproteins to recognize infected cells. The prevailing view is the reservoir for HIV is not latent but is constantly releasing virus particles in amounts sufficient to rapidly rekindle viremia upon therapy interruption. Consequently, these cells must have viral envelope glycoprotein on their surfaces and should be recognized by appropriate targeting antibodies. We are working toward this test by characterizing anti-Env monoclonal antibodies obtained from Drs. Lewis, DeVico and Guan, in addition to examining antibodies that are more broadly available. We hope to soon initiate pilot studies in macaques, that will be needed to secure durable funding for this study.

3) ADCC in natural virus suppression. A small fraction of HIV+ individuals suppress HIV replication to very low levels through natural responses independent of antiretroviral therapy. Variously termed elite controllers (EC), elite suppressors (ES) or, in our case natural virus suppressors (Sajadi et al., 2007), these individuals provide important examples of the potential for host immunity to contain HIV and slow or eliminate disease progression.

Virology, immunology and genetic studies have uncovered mechanisms responsible for this remarkable capacity to evade HIV disease. Replication-competent viruses were isolated from a subset of these individuals (Blankson et al., 2007). These virus strains showed normal modulation of MHC class I expression (Nou et al., 2009) as would be expected for viruses with functional Nef indicating that elite control is not the result of attenuated virus infection but is an acquired host response. Our own data (Riedel, 2009) showed evidence for a damaged γδ T cell repertoire in natural viral suppressors, that is consistent with a virulent, primary infection. While these studies are still incomplete, they argue that host responses subsequent to virulent infection, controlled HIV disease before irreparable damage to the immune system.

Mechanisms of immunity among elite controllers are predictably complex. Cellular immune responses have received the most attention because of the increased frequency for protective MHC class I alleles like HLA-B*57 (Migueles et al., 2000), compared to HIV progressor or uninfected control groups (Pereyra et al., 2008). Elite patients (viremia < 50 copies vRNA/ml plasma) maintain strong cellular responses to Gag epitopes that were associated with IFNγ and IL-2 secretion (Pereyra et al., 2008). These functional CD8+ T cell responses are associated with virus control (Betts et al., 2006) but curiously, virus suppression is maintained even when CTL escape mutations are selected (Bailey et al., 2006).

The role for protective antibody responses is more controversial. Neutralizing antibody levels were lower among elite controllers compared to viremic patients (Bailey et al., 2006; Pereyra et al., 2008) although memory B cells can produce broadly neutralizing antibodies after in vitro activation (Guan et al., 2009). These data suggest that neutralizing antibody responses may have been important for the initial control of HIV disease, but decline in the absence of viremia. In addition to virus neutralization, antibodies might control disease through antibody-dependent cellular cytotoxicity. Vaccine-elicited antibodies with ADCC activity were significantly associated with protection from SIV in a rhesus challenge model (Gomez-Roman et al., 2005). In passive transfer studies, mutagenesis of the Fc region in normally protective human monoclonal antibodies destroyed the capacity for binding to FcR and reduced their ability to protect against infection (Burton). Serum antibodies capable of mediating ADCC are also present in HIV controllers, at levels significantly higher than for viremic individuals (titers > 10,000 compared to ~1,000 for viremic patients) (Lambotte et al., 2009). Thus, ADCC is a potential mechanism for controlling HIV and appropriate antibodies are present at high levels in elite patients. High levels of ADCC antibodies will require potent effector cells to mediate durable virus suppression. Two likely effector subsets are Vγ2Vδ2 T cells and NK cells.

The CD16+/CD56+ NK cells can be effectors in ADCC but they are poorly studied in elite controller patients. In one study of 8 elite patients, 4 had high levels of NK-mediated inhibition of HIV replication, these individuals also had the fewest activating KIR and were all haplotype A (REF). Mavilioâ?Ts group showed a relationship between virus suppression and NK cell phenotype (Brunetta, 2009), again suggesting a relationship between disease and NK activity. Neither group studied ADCC activity of NK cells in any HIV+ patient group. Our studies have concentrated on γδ T cells, especially a subset expressing the Vγ2Vδ2 T cell receptor that shows strong effector activity in ADCC. This cell population is decreased significantly in HIV progressors (Enders, Bordon) and is not regained over 1-2 years of HAART therapy (Hebbeler et al., 2008). We have found higher levels of Vγ2Vδ2 cells and higher responses to phosphoantigens in patients with average > 8.7 years of effective antiviral treatment (Cummings et al., 2008) suggesting a slow recovery is possible. When we examined Vγ2Vδ2 cell levels in an elite patient cohort (Sajadi et al., 2007), we observed twice the abundance of Vγ2Vδ2 cells as was found in healthy controls (Riedel, 2009), far above the levels expected for anyone with progressing HIV disease (Bordon). The Vγ2Vδ2 cells in our elite patient group were responsive to phosphoantigen stimulation, the expanded cells were cytotoxic for Daudi B cell targets and expressed the CD16+/CD56+ phenotype (unpublished). These studies required uninfected controls matched for age, gender and race, because we found lower levels of Vγ2Vδ2 T cells in healthy African Americans (0.5% of total lymphocytes) compared to healthy Caucasians (4.0% of total lymphocytes) (Cairo, et al., submitted). Elevated Vγ2Vδ2 T cells may be a source of ADCC effector cells in these elite patients.

The increased levels of Vγ2Vδ2 T cells in elite patients might regulate other cell subsets that participate in ADCC. We know activated Vγ2Vδ2 cells express 4-1BB ligand that interacts with 4-1BB on NK cells to stimulate NK cell cytotoxicity; this requirement was partly substituted by cell lines constitutively expressing 4-1BBL (Chapoval, submitted). Activated NK cells will be CD16+/CD56+ and capable of ADCC function. Thus, we have two discrete mechanisms, ADCC and NK cell regulation, that might explain how increased Vγ2Vδ2 T cells in elite patients can contribute to natural virus control by providing cytotoxic effector cells for ADCC. Activated Vγ2Vδ2 cells triggered by antibody binding to FcR (Virgine, 2000) secrete TNF-α and other pro-inflammatory cytokines that will affect a broad variety of immune cell types.

We aim to understand factors regulating Vγ2Vδ2 T cells in this elite patient group and the potential impact on viral immunity. In particular, we want to test the possibility that increased Vγ2Vδ2 T cells provide an effector cell subset for ADCC that could be working with non-neutralizing antibodies to maintain control of viremia in elite patients. This mechanism would cooperate with CD8+ CTL to achieve durable virus suppression. Next, we want to test the hypothesis that increased Vγ2Vδ2 T cells provide a source for costimulation that will increase NK cell activity. A dual regulation of Vγ2Vδ2 T cells and NK cells could provide an important component in the overall picture for elite viral control. In cancer, a role for ADCC has been confirmed in clinical studies. The F/F genotype for FcγRIIIa genes produces a weak binding Fc receptor compared to the V/V genotype receptor that binds more strongly to Fc regions of IgG (REF). Cancer patients treated with monoclonal antibodies against lymphoma (Rituximab), EGFR (Cetuximab) or HER-2 (Trastuzumab) had response rates that reflected their FcγRIIIa genotype, with F/F patients having approximately half the response rate found in V/V patients (REF). We predict that our elite patient group w ill be over-represented for the V158 allele of FcγRIIIa, consistent with ADCC being important for virus control. Genotyping studies are included in this application. Studies in this cohort of African American elite controllers may be useful for understanding the interrelatedness of γδ and NK cell subsets and the potential impact of FcγRIIIa genotype or KIR haplotype on cell levels and function.


Urban, E.M., Li, H., Armstrong, C., Focaccetti, C., Cairo, C. and Pauza, C.D. (2009). Control of CD56 expression and tumor cell cytotoxicity in human Vgamma2Vdelta2 T cells. BMC Immunology (in press).

Li, H. and Pauza, C.D. (2009). Differential effects of PPARγ ligands 15-deoxy-Î"12,14-prostaglandin J2 (15d-PGJ2) and rosiglitazone on human Vgamma2Vdelta2 T cells. PlosOne (in press).

Poonia, B., Pauza, C.D. and Salvato, M.S. (2009). Role of Fas/FasL pathway in SIV or HIV disease. Retrovirology (in press).

Djavani, M. M., Crasta, O. R., Zapata, J. C., Fei, Z., Folkerts, O., Sobral, B., Swindells, M., Bryant, J. L., Davis, H., Pauza, C. D., Lukashevich, I. S., Hammamieh, R., Jett, M., and Salvato, M. S. (2007). Early blood profiles of virus infection in a monkey model for Lassa Fever. J. Virology in press.

Poonia, B., Salvato, M. S., Yagita, H., Maeda, T., Okumura, K., and Pauza, C. D. (2009). Treatment with anti-FasL antibody preserves memory lymphocytes and virus-specific cellular immunity in macaques challenged with simian immunodeficiency virus. Blood 114(6), 1196-204.

Riedel, D. J., Sajadi, M. M., Armstrong, C. L., Cummings, J. S., Cairo, C., Redfield, R. R., and Pauza, C. D. (2009). Natural viral suppressors of HIV-1 have a unique capacity to maintain gammadelta T cells. AiIDS 23(15), 1955-64.

Li, H., Peng, H., Ma, P., Ruan, Y., Su, B., Ding, X., Xu, C., Pauza, C. D., and Shao, Y. (2008). Association between Vgamma2Vdelta2 T cells and disease progression after infection with closely related strains of HIV in China. Clin Infect Dis 46(9), 1466-72. PMC2430745

Hebbeler, A. M., Propp, N., Cairo, C., Li, H., Cummings, J. S., Jacobson, L. P., Margolick, J. B., and Pauza, C. D. (2008). Failure to restore the Vgamma2-Jgamma1.2 repertoire in HIV-infected men receiving highly active antiretroviral therapy (HAART). Clin Immunol 128(3), 349-57.

Cummings, J. S., Cairo, C., Armstrong, C., Davis, C. E., and Pauza, C. D. (2008). Impacts of HIV infection on Vgamma2Vdelta2 T cell phenotype and function: a mechanism for reduced tumor immunity in AIDS. J Leukoc Biol 84(2), 371-9.

Cairo, C., Propp, N., Auricchio, G., Armstrong, C. L., Abimiku, A., Mancino, G., Colizzi, V., Blattner, W., and Pauza, C. D. (2008). Altered cord blood gammadelta T cell repertoire in Nigeria: possible impacts of environmental factors on neonatal immunity. Mol Immunol 45(11), 3190-7.

Cairo, C., Mancino, G., Cappelli, G., Pauza, C. D., Galli, E., Brunetti, E., and Colizzi, V. (2008). Vdelta2 T-lymphocyte responses in cord blood samples from Italy and Cote d'Ivoire. Immunology 124(3), 380-7.

Alexander, A. A., Maniar, A., Cummings, J. S., Hebbeler, A. M., Schulze, D. H., Gastman, B. R., Pauza, C. D., Strome, S. E., and Chapoval, A. I. (2008). Isopentenyl pyrophosphate-activated CD56+ {gamma}{delta} T lymphocytes display potent antitumor activity toward human squamous cell carcinoma. Clin Cancer Res 14(13), 4232-40. PMC2614380

Li, H., Luo, K., and Pauza, C. D. (2008). TNF-alpha is a positive regulatory factor for human Vgamma2 Vdelta2 T cells. J Immunol 181(10), 7131-7.

Zheng, L., Yang, Y., Guocai, L., Pauza, C. D., and Salvato, M. S. (2007). HIV Tat Protein Increases Bcl-2 Expression in Monocytes Which Inhibits Monocyte Apoptosis Induced by Tumor Necrosis Factor-Alpha-Related Apoptosis-Induced Ligand. Intervirology 50(3), 224-8.

Li, H., Deetz, C. O., Zapata, J. C., Cairo, C., Hebbeler, A. M., Propp, N., Salvato, M. S., Shao, Y., and Pauza, C. D. (2007). Vaccinia Virus Inhibits T Cell Receptor-Dependent Responses by Human gamma delta T Cells. J Infect Dis 195(1), 37-45.

Hebbeler, A. M., Cairo, C., Cummings, J. S., and Pauza, C. D. (2007). Individual Vgamma2-Jgamma1.2+ T cells respond to both isopentenyl pyrophosphate and Daudi cell stimulation: generating tumor effectors with low molecular weight phosphoantigens. Cancer Immunol Immunother 56(6), 819-29.

Cairo, C., Hebbeler, A. M., Propp, N., Bryant, J. L., Colizzi, V., and Pauza, C. D. (2007). Innate-like gammadelta T cell responses to mycobacterium Bacille Calmette-Guerin using the public Vgamma2 repertoire in Macaca fascicularis. Tuberculosis (Edinb) 87(4), 373-83.

Tikhonov, I., Deetz, C. O., Paca, R., Berg, S., Lukyanenko, V., Lim, J. K., and Pauza, C. D. (2006). Human Vgamma2Vdelta2 T cells contain cytoplasmic RANTES. Int Immunol 18(8), 1243-51.

Deetz, C. O., Hebbeler, A. M., Propp, N. A., Cairo, C., Tikhonov, I., and Pauza, C. D. (2006). Gamma interferon secretion by human Vgamma2Vdelta2 T cells after stimulation with antibody against the T-cell receptor plus the Toll-Like receptor 2 agonist Pam3Cys. Infect Immun 74(8), 4505-11.

Ahuja, S. K., Aiuti, F., Berkhout, B., Biberfeld, P., Burton, D. R., Colizzi, V., Deeks, S. G., Desrosiers, R. C., Dierich, M. P., Doms, R. W., Emerman, M., Gallo, R. C., Girard, M., Greene, W. C., Hoxie, J. A., Hunter, E., Klein, G., Korber, B., Kuritzkes, D. R., Lederman, M. M., Malim, M. H., Marx, P. A., McCune, J. M., McMichael, A., Miller, C., Miller, V., Montagnier, L., Montefiori, D. C., Moore, J. P., Nixon, D. F., Overbaugh, J., Pauza, C. D., Richman, D. D., Saag, M. S., Sattentau, Q., Schooley, R. T., Shattock, R., Shaw, G. M., Stevenson, M., Trkola, A., Wainberg, M. A., Weiss, R. A., Wolinsky, S., and Zack, J. A. (2006). A plea for justice for jailed medical workers. Science 314(5801), 924-5.