Dr. Linda Baum is interested in the role of cell surface carbohydrates and endogenous lectins in the maturation and function of cells of the immune system.
T-cells mature in the thymus and then migrate to organs such as spleen and lymph nodes, where they participate in the immune response to foreign invaders. Baum and her colleagues have found that a carbohydrate binding protein termed galectin-1 is expressed in human and murine thymus, lymph nodes and spleen. This endogenous lectin participates in the trafficking of T-lymphocytes from the circulation into these tissues and also mediates adhesion of T-cells to stromal cells within the organs. In addition, galectin-1 induces programmed cell death of specific populations of T-cells at unique points in development, identifying a role for galectin-1 in modulating the immune response. Baum's lab has recently found novel immune system functions for other members of the galectin family, including galectins-3 and -9, such as regulating B-cell survival and dendritic cell function.
Baum's current work focuses on identifying the cell surface counter-receptors which bind various galectins and participate in galectin-mediated cell adhesion, activation and apoptosis; and dissecting the structural features of these molecules essential to these distinct functions. She and her associates use a combination of cellular and biochemical assays to understand the mechanism of galectin functions.
Selected Cancer-Related Publications:
Bi S, Hong PW, Lee B, Baum LG. Galectin-9 binding to cell surface protein disulfide isomerase regulates the redox environment to enhance T-cell migration and HIV entry. Proc Natl Acad Sci U S A. 2011 Jun 28;108(26):10650-5. Epub 2011 Jun 13.
Liu SD, Whiting CC, Tomassian T, Pang M, Bissel SJ, Baum LG, Mossine VV, Poirier F, Huflejt ME, Miceli MC. Endogenous galectin-1 enforces class I-restricted TCR functional fate decisions in thymocytes. Blood. 2008 Jul 1;112(1):120-30. Epub 2008 Mar 6.
Valenzuela H, Pace KE, Cabrera PV, White R, Porvari K, Kaija H, Vihko P, Baum LG. O-glycosylation regulates LNCaP prostate cancer cell susceptibility to apoptosis induced by galectin-1. Cancer Res. 2007; 67:6155-62.
Toscano MA, Bianco GA, Ilarregui JM, Croci DO, Correale J, Hernandez JD, Zwirner NW, Poirier F, Riley EM, Baum LG, Rabinovich GA. Differential glycosylation of T(H)1, T(H)2 and T(H)-17 effector cells selectively regulates susceptibility to cell death. Nat Immunol. 2007.
Cabrera PV, Amano M, Mitoma J, Chan J, Said J, Fukuda M, Baum LG. Haploinsufficiency of C2GnT-I glycosyltransferase renders T lymphoma cells resistant to cell death. Blood. 2006.