Microbiology and Immunology
Uniformed Services University of the Health Sciences
Department of Microbiology and Immunology
4301 Jones Bridge Road
Bethesda, Maryland 20814-4799
Phone: (301) 295-3401
FAX: (301) 295-1545
Christopher C. Broder
Professor and Director, Emerging Infectious Diseases Graduate Program
Ph.D., University of Florida, 1989
Research: Enveloped Virus Entry and Tropism
We are pursuing structural and functional analyses on the interactions between enveloped viruses and their cellular receptors through immunological, biochemical, and genetic approaches with an emphasis on the expression of recombinant cDNAs in the vaccinia virus system. HIV-1 and new emerging paramyxovirus agents are the two main areas of research work presently being pursued. The goals of our work are to identify the steps and requirements of viral envelope glycoprotein (Env)-mediated membrane fusion, the determinants of viral tropism, the discovery of new viral receptors, and the mechanism of Env-mediated fusion. A detailed understanding of these processes will lead to the discovery of new methods of intervention.
Current work on HIV-1 includes the Env glycoprotein (gp120/gp41) mediated fusion mechanism and its interaction with CD4 and coreceptors. The HIV-1 Env serves two functions that are critical in the replication cycle of the virus: binding to host cells and mediating membrane fusion through what is believed to be receptor induced conformational alterations in its structure. In earlier work we identified two distinct cofactors (CXCR4/CCR5) for HIV-1 Env-mediated fusion and virus infection. These molecules are members of the chemokine receptor superfamily, and are now recognized as actual coreceptors for HIV-1 and they influence both the species and cell-type tropism of the virus. We are engaged in an extensive analysis of the roles these coreceptors play in the fusion process on the molecular level, and what role they may play in HIV-1 pathogenesis.
We are also interested in the structure of these viral envelope glycoproteins with particular emphasis on the immunological characteristics of the native glycoproteins. With the use of recombinant vaccinia virus expressed HIV-1 Env we have carried out an extensive analysis of the antigenic structure of native oligomeric Env, with particular emphasis in anti-Env monoclonal antibody development and characterization, and use of oligomeric Env as a vaccine immunogen, otherwise known as gp140. Ongoing research work includes the analysis of HIV-1 primary isolate-derived oligomeric gp140 preparations from a host of alternate HIV-1 clades, including a variety of genetically modified versions of the proteins with the goal of enhancing a neutralizing antibody response when used in small animals. In addition, in collaboration with other laboratories we are pursuing novel prime-boost vaccination strategies, with particular HIV-1 isolate Env proteins, using Venezuelan Equine Encephalitis (VEE) replicons and soluble oligomeric gp140 immunogen preparations in small animals and non-human primates.
The second area of work is relatively new and is the investigation Hendra virus and Nipah virus, which are newly emerging and highly lethal zoonotic agents. These studies are in collaboration with several scientists located at CSIRO Livestock Industries, Australian Animal Health Laboratory, Geelong, Victoria, one of only 4 facilities in the world where zoonotic BSL-4 agents may be researched. Both viruses are new members of the Paramyxoviridae, enveloped, negative-sense RNA viruses, and are now the prototypic members of a new Genus, Henipahvirus. They are related to the Morbilliviruses, of which Human Measles virus is a member, yet they are uniquely distinct from all other known Paramyxoviruses, both on the genomic molecular level as well as their biological, species tropism characteristics. Both viruses are classified as zoonotic BSL-4 agents. Hendra virus emerged in 1994, and was isolated from fatal cases of respiratory disease in horses and humans. Later in 1998-1999, an outbreak of severe encephalitis in people with close contact exposure to pigs in Malaysia and Singapore occurred. In all, more than 276 cases of encephalitis, including 106 deaths, had been reported a near 40% fatality rate upon infection. Pigs appeared to be an amplifier of the Nipah virus, and these viruses can also be economically devastating: over 1.2 million pigs were slaughtered to stem the Nipah virus outbreak. They appear to infect through the respiratory system initially and are capable of causing viremia. Hendra and Nipah both have broad species tropism, which is unusual because most paramyxoviruses are species restricted and do not have other reservoirs in nature. Current evidence points to several species of flying foxes (large Australian fruit bats).
The potential to be weaponized and used as biological warfare agents is clearly possible. They may be amplified in cell culture or embryonated chicken eggs, and could be used as a terror weapon targeting humans as well as livestock, the later which would serve as virus amplifiers. Recent evidence has also indicated that nosocomial transmissibility of Nipah virus from patients with encephalitis to healthcare workers is also possible. There are no existing antiviral therapies effective against these viruses, and the only therapies in existence to any viruses in the paramyxovirus family are live-attenuated vaccines. We have developed recombinant gene expression systems to study the attachment and membrane fusion-entry mechanisms of these viruses, and are developing novel reagents which may serve as potential vaccines as well as specifically blocking virus infection and spread. We are also engaged in recombinant virus-like particle formation and assembly for reagent development and to understand the requirements of particle formation in these novel viral agents.
Broder, C.C., D.S. Dimitrov, R. Blumenthal, and E.A. Berger. The Block to HIV-1 Envelope Glycoprotein-Mediated Membrane Fusion in Animal Cells Expressing Human CD4 can be Overcome by a Human Cell Component(s). Virology 193:483-491, 1993.
Broder, C.C., O. Nussbaum, W.G. Gutheil, W.W. Bachovchin, and E.A. Berger. CD26 antigen and HIV fusion? Science. 264:1156-1159, 1994.
Earl, P.L., C.C. Broder, D. Long, S. Lee, J. Peterson, S. Chakrabarti, R.W. Doms, and B. Moss. Native Oligomeric Forms of HIV-1 Envelope Glycoprotein Elicit a Diverse Array of Monoclonal Antibody Reactivities. J. Virol. 68: 3015-3026, 1994.
Broder, C.C., P.L. Earl, D. Long, B. Moss, and R.W. Doms. Antigenic Implications of HIV-1 Envelope Glycoprotein Quaternary Structure: Oligomer-Specific and -Sensitive Monoclonal Antibodies. Proc. Natl. Acad. Sci. USA. 91:11699-11703, 1994.
Broder, C.C. and E.A. Berger. Fusogenic Selectivity of the Envelope Glycoprotein is a Major Determinant of Human Immunodeficiency Virus Type-1 Tropism for CD4+ T-Cell Lines vs. Primary Macrophages. Proc. Natl. Acad. Sci. USA. 92:9004-9008, 1995.
Feng, Y., C.C. Broder, P.E. Kennedy, and E.A. Berger. HIV-1 Entry Cofactor: Functional cDNA Cloning of a Seven-Transmembrane, G Protein-Coupled Receptor. Science 272:872-877, 1996.
Alkhatib*, G., C. Combadiere*, C.C. Broder*, Y. Feng*, P.E. Kennedy*, P.M. Murphy, and E.A. Berger. CC CKR5: a RANTES, MIP-1 alpha , MIP-1 beta Receptor as a Fusion Cofactor for Macrophage-Tropic HIV-1. Science 272:1955-1958, 1996.
Earl, P.L., C.C. Broder, R.W. Doms, and B. Moss. Epitope Map of Human Immunodeficiency Virus Type-1 gp41 Derived From 47 Monoclonal Antibodies Produced by Immunization with Oligomeric Envelope Protein. J. Virol. 71:2674-2684, 1997.
Dimitrov, D.S. and C.C. Broder. HIV and Membrane Receptors. Landes Bioscience, Austin, TX, 1997.
Lee, B., J. Rucker, R.W. Doms, M. Tsang, X. Hu, M. Dietz, R. Bailer, L.J. Montaner, C. Gerard, N. Sullivan, J. Sodroski, T.S. Stantchev, C.C. Broder. Beta-Chemokine MDC and HIV-1 Infection. Science. 251(5376), 1998.
Dimitrov, D.S., D. Norwood, T.S. Stantchev, Y. Feng, X. Xiao, and C.C. Broder. A Mechanism of Resistance to HIV-1 Entry: Inefficient Interactions of CXCR4 with CD4 and gp120 in Macrophages. Virology 259:1-6, 1999.
Xiao X, L. Wu, TS Stantchev, Y-R. Feng, S Ugolini, H Chen, Z Shen, C.C. Broder, Q.J. Sattentau, and D.S. Dimitrov. Constitutive Cell Surface Association Between CD4 and CCR5. Proc. Natl. Acad. Sci. USA. 96:7496-7501, 1999.
Chabot, D.J., P-F. Zhang, G.V. Quinnan, and C.C. Broder. Mutagenesis of CXCR4 Identifies Important Domains for HIV-1 X4 Isolate Envelope-Mediated Membrane Fusion and Virus Entry and Reveals Cryptic Coreceptor Activity for R5 Isolates. J. Virol. 73:6598-6609, 1999.
Xiao, X., D. Norwood, Y-R. Feng, M. Moriuchi, H. Moriuchi, A. Jones-Trower, T.S. Stantchev, C.C. Broder, and D.S. Dimitrov. Inefficient Formation of a Complex between CXCR4, CD4 and gp120 in U937 Clones Resistant to X4 gp120-gp41-Mediated Fusion. Exp. Mol. Path. 68:139-146, 2000.
Chabot, D.J., H. Chen, D.S. Dimitrov, and C.C. Broder. N-linked Glycosylation in CXCR4 Masks Coreceptor Function for CCR5-Dependent HIV-1 Isolates. J. Virol. 74:4404-4413, 2000.
Stantchev, T.S. and C.C. Broder. Consistent and Significant Beta-chemokine Inhibition of HIV-1 Envelope-mediated Membrane Fusion in Primary Macrophages. J Infect Dis. 182:68-78. 2000.
Chabot, D.J. and C.C. Broder. Substitutions in a Homologous Region in the Extracellular Loop-2 of CXCR4 and CCR5 Alter Coreceptor Activities for HIV-1 Fusion and Entry. J. Biol. Chem. 275:23774-23782. 2000.
Bossart, K.N., L.F. Wang, B.T. Eaton, and C.C. Broder. Functional Expression and Membrane Fusion Tropism of the Envelope Glycoproteins of Hendra Virus. Virology. 290:121-135. 2001.
Bossart, K.N., L.F. Wang, B.T. Eaton, K.B. Chua, S.K. Lam, and C.C. Broder. Membrane Fusion Tropism and Heterotypic Functional Activities of the Nipah Virus and Hendra Virus Envelope Glycoproteins. J. Virol. Nov, 76:11186-11198. 2002.
Xiao, X., Phogat, S, Shu, Y., Phogat, A., Chow, Y.H., Wei, O.L., Goldstein, H., Broder, C.C., Dimitrov, D.S. Purified Complexes of HIV-1 Envelope Glycoproteins with CD4 and CCR5(CXCR4): Production, Characterization and Immunogenicity. Vaccine. 21:4275-84. 2003.
Markovic, I., Stantchev, T.S., Fields, K.H., Tomic, M., Weiss, C.D., Broder, C.C., Strebel, K, and Clouse, K.A. Thiol/Disulfide Exchange is a Pre-Requisite for CXCR4-Tropic HIV-1 Envelope-Mediated T Cell Fusion During Viral Entry. Blood, Mar 1;103(5):1586-94. 2004.
Quinnan, Jr., G.V., Y. Xiao-Fang, M.G. Lewis, P-F, Zhang, G. Sutter, P. Silvera, M. Dong, A. Choudhary, P.T. N. Sarkis, P. Bouma, Z. Zhang, D.C. Montefiori, T.C. VanCott, and C.C. Broder. Protection of Rhesus Monkeys against Infection with Minimally Pathogenic, Simian-Human Immunodeficiency Virus: Correlations with Neutralizing Antibodies and Cytotoxic T Cells. J. Virol. 79(6):3358-69. 2005.
Bossart, K.N., G. Crameri, A.S. Dimitrov, B.A. Mungall, Y.R. Feng, J.R. Patch, A. Choudhary, L.F. Wang, B.T. Eaton, and C.C. Broder. Receptor Binding, Fusion Inhibition, and Induction of Cross-Reactive Neutralizing Antibodies by a Soluble G Glycoprotein of Hendra Virus. J. Virology, 79(11):6690-702. 2005.
Bonaparte, M. I., A. S. Dimitrov, K. N. Bossart, G. Crameri, B. A. Mungall, K. A. Bishop, V. Choudhry, D. S. Dimitrov, L.-F. Wang, B. T. Eaton, and C. C. Broder. 2005. Ephrin-B2 Ligand is a Functional Receptor for Hendra Virus and Nipah Virus. Proc Natl Acad Sci U S A. 102(30):10652-7. 2005.
Bossart, K.N., B.A. Mungall, G. Crameri, L.F. Wang, B.T. Eaton, and C.C. Broder. Inhibition of Henipavirus Fusion and Infection by Heptad-derived Peptides of the Nipah Virus Fusion Protein. Virology Journal. 2(1):57. 2005.
Zhu, Z., A. S. Dimitrov, K. N. Bossart, G. Crameri, K. A. Bishop, V. Choudhry, B. A. Mungall, Y. R. Feng, A. Choudhary, M. Y. Zhang, Y. Feng, L. F. Wang, X. Xiao, B. T. Eaton, C. C. Broder, and D. S. Dimitrov. Potent Neutralization of Hendra and Nipah Viruses by Human Monoclonal Antibodies. J. Virol. 80(2):891-9. 2006.
Eaton, B.T., C.C. Broder, and L.F. Wang. Hendra and Nipah viruses: pathogenesis and therapeutics. Current Molecular Medicine 5:805-815. 2006.
Bossart, K.N. and C.C. Broder. Developments towards effective treatments for Nipah and Hendra virus infection. Expert Review of Anti-infective Therapy. 4(1):43-55. 2006.
Zhu, Z., A.S. Dimitrov, S. Chakraborti, D. Dimitrova, X. Xiao, C.C. Broder and D.S. Dimitrov. Development of Human Monoclonal Antibodies against Diseases caused by Emerging and Biodefense-Related Viruses. Expert Review of Anti-infective Therapy. 4(1):57-66. 2006.
Eaton, B.T., C.C. Broder, D. Middleton, and L.F. Wang. Hendra and Nipah viruses: different and dangerous. Nat Rev Microbiol. 4(1):23-35. 2006.
Mungall BA, Middleton D, Crameri G, Bingham J, Halpin K, Russell G, Green D, McEachern J, Pritchard LI, Eaton BT, Wang LF, Bossart KN, Broder CC. A feline model of acute Nipah virus infection and protection with a soluble glycoprotein-based subunit vaccine. Virol. 80(24):12293-302. 2006.
Zhang MY, Choudhry V, Sidorov IA, Tenev V, Vu BK, Choudhary A, Lu H, Stiegler GM, Katinger HW, Jiang S, Broder CC, Dimitrov DS. Selection of a novel gp41-specific HIV-1 neutralizing human antibody by competitive antigen panning. J Immunol Methods. 317(1-2):21-30. 2006.
Patch JR, Crameri G, Wang LF, Eaton BT, Broder CC. Quantitative analysis of Nipah virus proteins released as virus-like particles reveals central role for the matrix protein. Virology Journal. Jan 4;4:1. 2007.
Bishop KA, Stantchev TS, Hickey AC, Khetawat D, Bossart KN, Krasnoperov V, Gill P, Feng YR, Wang L, Eaton BT, Wang LF, Broder CC. Identification of Hendra virus G glycoprotein residues that are critical for receptor binding. J Virol. 81(11):5893-901. 2007.
Zhang, P.F., Cham, F., Dong, M., Choudhary, A., Bouma, P., Zhang, Z., Shao, Y., Feng, Y.R., Wang, L., Mathy, N., Voss, G., Broder, C.C., Quinnan, G.V., Jr. Extensively cross-reactive anti-HIV-1 neutralizing antibodies induced by gp140 immunization. Proc Natl Acad Sci U S A. Jun 12;104(24):10193-8. 2007.
Mungall, B.A., Middleton, D., Crameri, G., Halpin, K., Bingham, J., Eaton, B.T., Broder, C.C. (From The Cover). Vertical transmission and fetal replication of Nipah virus in an experimentally infected cat. J. Infect. Dis. 196(6):812-6. 2007.
Bossart, K.N., Tachedjian, M., McEachern, J.A., Crameri, G., Zhu, Z., Dimitrov, D.S., Broder C.C.,Wang, L.F.. Functional studies of host-specific ephrin-B ligands as Henipavirus receptors. Virology 372(2):357-71. 2008.
Derek, D., Schornberg, K.L., Stantchev, T.S., Bonaparte, M.I., Delos, S.E., Bouton, A.H., Broder, C.C. and White, J.M. Cell Adhesion Promotes Ebola Virus Envelope Glycoprotein-Mediated Binding and Infection. J Virol. 82(14):7238-42, 2008.
Zhang, M.Y., Vu, B.K., Choudhary, A., Lu, H., Humbert, M., Ong, H., Alam, M., Ruprecht, R.M., Quinnan, G., Jiang S., Montefiori, D.C., Mascola, J.R., Broder, C.C., Haynes, B.F., Dimitrov, D.S. Cross-Reactive Human Immunodeficiency Virus Type 1- Neutralizing Human Monoclonal Antibody which Recognizes A Novel Conformational Epitope on gp41 and Lacks Reactivity against Self Antigens. J Virol. 82(14):6869-79, 2008.
Xu, K., Rajashankar, K.R., Chan, Y.P., Himanen, J.P., Broder, C.C. and Nikolov, D.B. Host Cell Recognition by the Henipaviruses: Crystal Structures of the Nipah G Attachment Glycoprotein and Its Complex with Ephrin-B3. Proc Natl Acad Sci U S A. 105(29):9953-8. 2008.
Pavlin, J.A., Hickey, A.C., Ulbrandt, N., Chan, Y.P., Endy, T.P., Boukhvalova, M.S., Chunsuttiwat, S., Nisalak, A., Libraty, D.H., Green, S., Rothman, A.L., Ennis, F.A., Jarman, R., Gibbons, R.V. and Broder, C.C. Human Metapneumovirus Reinfection among Children in Thailand Determined by an Enzyme-Linked Immunosorbent Assay Using Purified Soluble Fusion Protein. J. Infect. Dis. 198(6):836-42. 2008.
Bishop, K.A., Hickey, A.C., Khetawat, D., Patch, J.R., Bossart, K.N., Zhu, Z., Wang, L.F., Dimitrov, D.S., Broder, C.C. Residues in the stalk domain of the Hendra virus G glycoprotein modulate conformational changes associated with receptor binding. J Virol. 82(22):11398-409. 2008.
Patch, J.R., Han, Z., McCarthy, S.E., Yan, L., Wang, L.F., Harty, R.N., Broder, C.C. The YPLGVG sequence of the Nipah virus matrix protein is required for budding. Virol J. 5(1):137. 2008.
Li, Y., Wang, J., Hickey, A.C., Zhang, Y., Li, Y., Wu, Y., Zhang, H., Yuan, J., Han, Z., McEachern, J., Broder, C.C., Wang, L.F., Shi, Z. Antibodies to Nipah or Nipah-like viruses in bats, China. Emerg Infect Dis. 14(12):1974-6 2008.
Bossart, K. N., and C. C. Broder. Paramyxovirus Entry. In S. Puhlmann and G. Simmons (ed.), Viral Entry into Host Cells. Landes Bioscience, Austin, TX. 2009.
Broder,C.C. Therapeutics and Vaccines against Hendra and Nipah Viruses. In M. Levine (ed), New Generation Vaccines-Fourth Edition, 2009.
Prabakaran P, Zhu Z, Xiao X, Biragyn A, Dimitrov AS, Broder, C.C., Dimitrov DS. Potent human monoclonal antibodies against SARS CoV, Nipah and Hendra viruses. Expert Opin Biol Ther. 9(3):355-68. 2009.
Dimitrova D, Choudhry V, Broder CC. Antibody fragment expression and purification. Methods Mol Biol. 525:491-8. 2009 .
Chan YP, Yan L, Feng YR, Broder CC. Preparation of recombinant viral glycoproteins for novel and therapeutic antibody discovery. Methods Mol Biol. 525:31-58. 2009.
Kaku Y, Noguchi A, Marsh GA, McEachern JA, Okutani A, Hotta K, Bazartseren B, Fukushi S, Broder CC, Yamada A, Inoue S, Wang LF. A neutralization test for specific detection of Nipah virus antibodies using pseudotyped vesicular stomatitis virus expressing green fluorescent protein. J Virol Methods. 160(1-2):7-13. 2009.
Blanco JC, Pletneva LM, Wieczorek L, Khetawat D, Stantchev TS, Broder CC, Polonis VR, Prince GA. Expression of Human CD4 and chemokine receptors in cotton rat cells confers permissiveness for productive HIV infection. Virol J. 6:57. 2009.
Pallister J, Middleton D, Crameri G, Yamada M, Klein R, Hancock TJ, Foord A, Shiell B, Michalski W, Broder CC, Wang LF. Chloroquine administration does not prevent Nipah virus infection and disease in ferrets. J Virol. 83(22):11979-82. 2009.
Bossart KN, Zhu Z, Middleton D, Klippel J, Crameri G, Bingham J, McEachern JA, Green D, Hancock TJ, Chan YP, Hickey AC, Dimitrov DS, Wang LF, Broder CC. PLoS Pathog. 5(10):e1000642. 2009.