Email: cbaldwin@vasci.umass.edu
C. Baldwin Vet & Animal Sciences Web Site

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

Cellular Immunity: Intracellular Microbes and gamma delta 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 gamma-interferon 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.

Our second major area of research evaluates gamma delta 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. We are studying how this subpopulation of T lymphocytes is activated by constitutively expressed molecules on macrophages and the ability of a killed leptospira vaccine to prime gamma delta T cells for recall responses to leptospira components. We are also interested in the role a lineage-specific cell-surface molecule of gamma delta T cells, known as WC1, plays in signal transduction and activation of these cells and understanding why expression of particular isoforms of WC1 correlates with functional differences of the T cells.

Representative publications:

Baldwin, C.L. and R. Goenka. (2006) Host Immune responses to the intracellular bacteria Brucella : does the bacteria instruct the host to facilitate chronic infection? Critical Reviews in Immunology, in press.

Herzig, C.T.A., S.L. Blumerman and C.L. Baldwin. (2006) Identification of three new bovine T cell receptor delta variable gene subgroups expressed by peripheral blood T cells. Immunogenetics, in press.

Blumerman, S., C. Herzig, F. Wang, P. Coussens, and C. Baldwin. Comparison of gene expression by co-cultured WC1 + g d and CD4 + a b T cells exhibiting a recall response to bacterial antigen. Molecular Immunology, in press.

Herzig, C., S. Blumerman, M-P. Lefranc and C. Baldwin. (2006) Bovine T cell receptor gamma variable and constant genes: combinatorial usage by circulating ?d T cells. Immunogenetics 58:138-151.

Rogers, A.N., D. Van Buren, B. Zou, K. Lahmers, C. Herzig, W.C. Brown, J.C. Telfer and C.L. Baldwin. (2006) Characterization of WC1 co-receptors on functionally distinct subpopulations of ruminant ?d T cells. Cell. Immunol. 239:151-161.

Blumerman, S., C. Herzig, A. Rogers and C.L. Baldwin. (2006) Differential TCR gene usage between WC1 - and WC1 + ruminant ?d T cell subpopulations including those responding to bacterial antigen. Immunogenetics 58:680-692.

Rogers, A ., D. G. VanBuren, E.E. Hedblom, M.E. Tilahun, J.C. Telfer and C.L. Baldwin. (2005) g d T cell function varies with the expressed WC1 coreceptor. J. Immunol. 174:3386-3393.

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.
Sathiyaseelan, T., B. Naiman, S. Welte, N. Machugh, S. J. Black and C. L. Baldwin (2002). "Immunological characterization of a gammadelta T-cell stimulatory ligand on autologous monocytes." Immunology 105(2): 181-9.

Murphy, E. A., J. Sathiyaseelan, M. A. Parent, B. Zou 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(4): 511-8.

Naiman, B. M., D. Alt, C. A. Bolin, R. Zuerner and C. L. Baldwin (2001). "Protective killed Leptospira borgpetersenii vaccine induces potent Th1 immunity comprising responses by CD4 and gammadelta T lymphocytes." Infect Immun 69(12): 7550-8.

Sathiyaseelan, J., X. Jiang and C. L. Baldwin (2000). "Growth of Brucella abortus in macrophages from resistant and susceptible mouse strains." Clin Exp Immunol 121(2): 289-94.