Cynthia L. Baldwin

Professor of Virology & Microbiology

Phone: 413-545-3167
Fax: 413-545-6326
Email: cbaldwin@vasci.umass.edu

Ph.D.: Cornell University, Immunology, 1983
Postdoctoral Training:
International Laboratory for Research on Animal
Diseases, Nairobi, Kenya

Cellular Immunity: Intracellular Microbes and gd T-cells

While macrophages are normally considered to be a primary cell for mediating innate immune responses by phagocytosing and destroying microbes that infect mammals, some microbial organisms including bacteria and protozoa have specifically adapted themselves to survive and replicate in host cells thereby "hiding" from protective immune responses. We study Brucella abortus, a bacterium that causes disease in a wide variety of agricultural animals and in people, to evaluate how some animals but not others successfully prevent infections by intracellular pathogens. We are particularly interested in the role of host cytokines, such as interleukins and interferons produced by T lymphocytes, in controlling the infection through their ability to activate macrophages for antimicrobial activities. In addition we are interested in identifying genes of the bacteria that facilitate their survival in host macrophages thus allowing them to establish chronic infections. To do this we utilize gene knock-out mice and produce knock-outs of bacterial genes in conjunction with collaborators.

Our second major area of research evaluates gd T cells, a subpopulation of T lymphocytes that comprise a major proportion of lymphocytes in mammals but whose role in mediating protective immunity is unclear at this time. Currently my lab is ascertaining whether these cells have immunological memory, how this subpopulation of T lymphocytes is activated by constitutively expressed molecules on macrophages as well as by bacterial components and how macrophages regulate their response. Finally, we interested in the role of a lineage-specific cell-surface molecule of gd T cells, known as WC1, in signal transduction and activation.

Third, we are evaluating the role of cellular immune responses in protection of cattle against infections with the bacteria Leptospira borgpetersenii serovar hardjo. We are particularly interested in the unique role played by gamma delta T cells. Along with CD4 T cells, these cells exhibit recall responses in vaccinated cattle. That is, they produce interferon-gamma in response to stimulation with the bacterial antigens. Using microarray technology we are comparing genes expressed by gamma delta T cells vs CD4 T cells in response to antigen stimulation following vaccination as a mechanism to ascertain their unique role in protective immune responses.

Representative recent publications:

Murphy E., Robertson G., Hagius S.D., Parent M., Roop M.R., Elzer P.H., and C.L. Baldwin (2002) MHC class I and II expression on macrophages containing a virulent strain of Brucella abortus measured using GFP-expressing brucellae and flow cytometry. FEMS Immunology and Medical Microbiology 33:191-200. PubMed Abstract

Parent M., Bellaire B., Murphy E.A., Roop R.M., and C.L. Baldwin (2002) Role of Brucella abortus siderophore 2,3-dihydroxybenzoic acid (DHBA) for survival in macrophages, trophoblasts and in vivo. Microbial Pathogenesis 32:239-248. PubMed Abstract

Sathiyaseelan T., Naimen B., Welte S., MacHugh N., Black S.J., and C.L. Baldwin (2002) Immunological characterization of a T cell stimulatory ligand on autologous monocytes. Immunology 105:181-189. PubMed Abstract

Murphy E., Parent M., Sathiyaseelan J., and C.L. Baldwin (2002) Immune control of Brucella abortus 2308 infections in BALB/c mice. FEMS Immunology and Medical Microbiology 33:191-200. PubMed Abstract

White A.M., Blumerman S., Naiman B., and C.L. Baldwin (2002) Expression of the bovine high affinity IL-12 receptor b2.Veterinary Immunology & Immunopathology 84:127-142. PubMed Abstract

Baldwin C.L., Sathiyaseelan T., Naiman B., White A.M., Brown R., Blumerman S., Rogers A., and S.J. Black (2002) Activation of bovine peripheral blood gd T cells for cell division and IFN-g production. Veterinary Immunology & Immunopathology 87:251-259. PubMed Abstract

Naiman B., Alt D., Bolin C.A., Zuerner R., and C.L. Baldwin (2001) Killed leptospira vaccine induces a potent Th1 immune response comprised of CD4 and gamma delta T lymphocytes. Infection and Immunity 69:7550-7558. PubMed Abstract

Murphy E., Sathiyaseelan J., and C.L. Baldwin (2001) Interferon-gamma is crucial for surviving a Brucella abortus infection in both resistant C57BL/6 and susceptible BALB/c mice.Immunology 103:511-518. PubMed Abstract

Sathiyaseelan J., Jiang X., Fernandes D., and C.L. Baldwin (2000) Growth of Brucella abortus in macrophages from resistant and susceptible mouse strains.Clinical and Experimental Immunology 121:289-294. PubMed Abstract

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