University at Buffalo
The Witebsky Center

The Witebsky Center
University at Buffalo
Bacteriology Host-Microbe Interactions Immunology Parasitology Virology
The Witebsky Center The Witebsky Center
Terry D. Connell

Terry D. Connell, Ph.D., Professor

Witebsky Center for Microbial Pathogenesis & Immunology
Department of Microbiology & Immunology
147 Biomedical Research Building
Phone: (716) 829-3364
Fax: (716) 829-3889

Molecular and Cellular Regulation of the Mucosal Immune Response

  Molecular Pathogenesis of Bordetella spp.:
Bacteria for Childhood Respiratory Disease

Research efforts in my laboratory are focused both in Immunologyand Bacterial Pathogenesis, two diverse fields of biomedical research for which I have two separate research groups.  Projects in both fields are available for graduate students and post-doctoral fellows.      

Regulation of Mucosal Immune Responses. A major focus of my laboratory is to investigate the cellular and molecular events which modulate mucosal immune responses.  We have demonstrated that LT-IIa and LT-IIb, two Type II heat-labile enterotoxins of Escherichia coli, are potent oral and nasal immunogens that have the capacity for augmenting humoral and cellular immune responses (See Figure below).  Using a variety of immunological and cellular techniques (including flow cytometry, FRET fluorescent detection, cytokine multiplex analysis, mutagenesis, and the use of transgenic mice), we are evaluating the manners in which these two immunomodulators productively interact with various lymphoid cells such as T cells, B cells, and dendritic cells to induce or suppress cytokine production, co-stimulatory ligand expression, and proliferation.  A practical outgrowth of these experiments is the potential to engineer novel recombinant vaccines by genetically fusing antigens from different pathogens to the immunomodulatory enterotoxins. We have shown that upon nasal immunization, these genetically-fused proteins elicit protective immune responses in animal challenge models. Other fusion proteins being produced are incorporating antigens from Haemophilus influenzae, hepatitis virus, and tuberculosis in an effort to produce new and effective vaccines.

Iron acquisition in the Bordetellae. A second focus of my laboratory is to investigate the mechanisms by which Bordetella pertussis, B. bronchiseptica, and B. avium, three gram-negative bacteria that infect the upper respiratory tract of children and domesticated animals, acquire essential nutrients required to colonize the respiratory tract and to sustain progressive infections. Iron (Fe) is one of the most important nutrients required by most, if not all infectious bacteria which must be obtained from the tissues and fluids of the infected host. Using proteomic, recombinant, immunological, and biochemical methods, we are unraveling the genetic and molecular components of these bacteria that mediate acquisition of Fe from host-derived heme, myoglobin, and hemoglobin.  We have identified a cluster of genes (bhuRSTUV) which encodes five proteins required for uptake of heme and a second gene cluster (rhuIR) which encodes for two heme-dependent regulatory proteins which control heme-dependent expression of the uptake systems (See Figure below).  Our current research is focused on analysis of these seven genes and expressed proteins.

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Editorial Board, Infection and Immunity, The American Society

Reviewer for:
European Journal of Immunology, Microbial Pathogenesis, Gene, Journal of Bacteriology, BioTechniques, Immunological Investigations, Medical Science Monitor, Microbiology, Trends in Microbiology, Molecular Microbiology, Applied and Environmental Microbiology, Archives of Microbiology

Grant reviewpanel HIBP, Host Interactions with Bacterial Pathogens, Center for Scientific Review, National Institutes of Health


Kirby, A.E. and T.D. Connell.  2004.  RhuR, an extracytoplasmic function (ECF) sigma factor
activator, is essential for heme‑dependent expression of the outer membrane heme and hemoprotein receptor of Bordetella aviumInfection & Immunity 72:896-907.
Hajishengallis, G., H. Nawar, R. Tapping, M.W. Russell, and T.D. Connell.  2004.  The type II heat- labile enterotoxins LT-IIa and LT-IIb and their respective B pentamers differentially induce and  regulate cytokine production in human monocytic cells.  Infection & Immunity 72:6351-58.
Hajishengallis, G., R.I. Tapping, M. H. Martin, H. Nawar, E. A. Lyle, M. W. Russell, and T. D.
Connell.  2005.  Toll-like receptor 2 mediates cellular activation by the B subunits of type II heat- labile enterotoxins.  Infection & Immunity.  73:1343-1349.
King, N.D., A.E. Kirby, and T.D. Connell.  2005.  Transcriptional control of the rhuIR bhuRSTUV heme acquisition locus in Bordetella aviumInfection & Immunity.  73:1613-1624.
Nawar, H.F., S. Arce, M.W. Russell, and T.D. Connell.  2005.  Mucosal adjuvant properties of mutant LT-IIa and LT-IIb enterotoxins that exhibit altered ganglioside-binding activities.    Infection & Immunity.  73:1330-1342.

Arce, S., H.F. Nawar, M.W. Russell, and T.D. Connell.   2005.  Differential binding of Escherichia coli enterotoxins LT-IIa and LT-IIb and of cholera toxin elicits differences in apoptosis, proliferation, and activation of lymphoid cells.  Infection & Immunity.  73:2718-27.
Hajishengallis, G., S. Arce, C. M. Gockel, T. D. Connell, and M.W. Russell.  2005.  Immunomodulation with enterotoxins for the generation of secretory immunity or tolerance: applications for oral infections.   Crit. Rev. Oral Biol. Med. 84:1104-1116.
van Ginkel, F.W., R. J. Jackson, N. Yoshino, Y. Hagiwara, D.J. Metzger, T.D. Connell, H.L. Vu, M. Martin, K. Fujihashi, and J.R. McGhee.  2005.  Enterotoxin-based mucosal adjuvants alter antigen trafficking and induce inflammatory responses in the nasal tract.  Infection & Immunity.  73:6892-6902.
Sebaihia, M.,, J. Preston, D.J. Maskell, H. Kuzmiak, T.D. Connell, N.D. King, P.E. Orndorff, D.M. Miyamoto, N.R. Thomson, D.  Harris, A. Goble, A. Lord, L. Murphy, M.A. Quail, S. Rutter, R. Squares, S. Squares, J. Woodward, J. Parkhill, and L. M. Temple.  2006.  Comparison of the genome  sequence of the poultry pathogen Bordetella avium with those of B. bronchiseptica, B. pertussis, and  B. parapertussis reveals extensive diversity in surface structures associated with host interaction.  J. of Bacteriology.  188:6002-15.
Nawar, H.F., S. Arce, M.W. Russell, and T.D. Connell.  2007.  Mutants of Type II heat-labile
enterotoxin LT-IIa exhibiting altered ganglioside-binding activities and diminished toxicities are potent mucosal adjuvants.  Infection & Immunity 72:621-33.
Arce, S., H.E. Nawar, G. Muehlinghaus, M.W. Russell, T.D Connell.  2007.  "In vitro induction of IgA- and IgM-secreting cells by cholera toxin depends on T-cell help and is mediated by CD154 up-regulation".  Infection & Immunity 75:1413-23.
Shuang, L.,  M. Wang, R. I. Tapping, V. Stepensky, H.F. Nawar, M. Triantafilou, K. Triantafilou, T. D. Connell, and G. Hajishengallis.  2007.  Ganglioside GD1a is an essential coreceptor for Toll-like Receptor 2 signaling in response to the B subunit of Type IIb enterotoxin.  J. of Biological Chemistry 282:7532-42.
Shuang, L. S., M. Wang, K. Triantafilou, M. Triantafilou, H.F. Nawar, M.W. Russell, T.D. Connell, and G. Hajishengallis.  2007.  The A subunit of Type IIb enterotoxin (LT-IIb) suppresses the proinflammatory potential of the B subunit and its ability to recruit and interact with TLR2.  J. of Immunology 178:4811-19.
King, N.D., K.F. Smith, and T.D. Connell.  2007.  "Expression of hurP, a gene encoding a prospective site 2 protease, is essential for heme-dependent induction of bhuR in Bordetella bronchiseptica."  J. of Bacteriology 189:6266-75.
Mocny, J., J. Olson, and T.D.  Connell.  2007.  The role of spontaneous loss of heme from hemoglobin and myoglobin in iron acquisition by Bordetella bronchiseptica.  Infection & Immunity 75:4857-4866.
Connell, T.D.  2007.  "Cholera toxin, LT-I, LT-IIa, and LT-IIb: the critical role of ganglioside-binding in immunomodulation by Type I and Type II heat-labile enterotoxins".  Expert Review of Vaccines. (Invited review, peer reviewed) 6:821-34.
Liang, SW., K.B. Hosur, S. Lu, H.F. Nawar, B.R. Weber, R.I. Tapping, T.D. Connell, and G.
Hajishengallis.  2009.  “Mapping of a microbial protein domain involved in binding and activation of the TLR2/TLR1 heterodimer”.  J. of Immunology 182:2978-85.
Taube, S. J. Perry, K. Yetming, S.P. Patel, H. Auble, L. Shu, H.F. Nawar, C.H. Lee, T.D. Connell, J. Shayman, and C.E. Wobus.  2009.  “Ganglioside-linked terminal sialic acid moieties on murine macrophages function as attachment receptors for murine noroviruses (MNV)”.  J. of Virology 83:4092-4101.
Liang, S., K.B. Hosur, H.F. Nawar, M.W. Russell, T. D. Connell, and G. Hajishengallis.  2009.  “In vivo and in vitro adjuvant activities of the B subunit of Type IIb heat-labile enterotoxin (LT-IIb-B5) from Escherichia coli.”  Vaccine 27:4302-4308.
Berenson, C.S.*, H.F. Nawar*, H.C. Yohe, D. Ashline, S. Castle, V.N. Reinhold, G. Hajishengallis, and T.D. Connell.  2010.  “Mammalian cell ganglioside-binding specificities of E. coli enterotoxins LT-IIb and variantLT-IIb(T13I)” .  Glycobiology 20:41-54.   * - co-first authors
Burgos, J., N.D. King-Lyon, and T.D. Connell.   2010.  Expression of BfrH, a putative siderophore receptor of Bordetella bronchiseptica, is regulated by iron, Fur1, and the extracellular function (ECF) sigma factor EcfI.  Infection & Immunity 78:1147-62.
Lee, C.H., H.F. Nawar, L. Mandell, S. Liang, G. Hajishengallis, and T.D. Connell.  2010.  “Enhanced antigen uptake by dendritic cells induced by the B pentamer of the Type II heat-labile enterotoxin LT-IIa requires engagement of TLR2”.  Vaccine 28:3696-3705.
Nawar, H.F., C.S. Berenson, G. Hajishengallis, H. Takematsu, L. Mandell, R.L. Clare, and T.D. Connell. 2010.  “Binding to gangliosides containing N-acetylneuraminic acid is sufficient to mediate the immunomodulatory properties of the non-toxic mucosal adjuvant LT-IIb(T13I)”.  Clinical and Vaccine Immunology 17: 969-78.
Nawar, H.F., N.D. King-Lyons, J.C. Hu, R.C. Pasek, and T.D. Connell.  2010.  LT-IIc, a new member of the type II heat-labile enterotoxin family encoded by an Escherichia coli strain obtained from a non-mammalian host.  Infection & Immunity 78: 4705 – 4713. 
Nawar, H.F., C.J. Greene, and T.D. Connell.  2010.  LT-IIc, a new member of the type II heat-labile enterotoxin family, exhibits potent immunomodulatory properties that are different from those induced by LT-IIa or LT-IIb.  Vaccine 29:721–727.