The objective of the proposed studies is to gain a comprehensive understanding of the lineal relationships, activation requirements, and functional capabilities of subpopulations of human Leu-3+ helper T (Th) cells. These studies will exploit the availability of two novel monoclonal antibodies, HB-10 and HB-11, and are designed to test the hypothesis that the immunoregulatory functions of human Leu-3+ Th cells are performed by distinct subsets which are recognizable by the expression of the HB-10 and HB-11 antigens and which represent sequential stages in post-thymic differentiation.
Our specific aims are to determine whether functionally immature Leu-3+HB-10+ cells can be induced to differentiate in vitro into functional helper T cells expressing the Leu-3+HB-10- phenotype. Subpopulations of Leu-3+ cells purified by fluorescence activated cell sorter (FACS) techniques will be stimulated with polyclonal activators or alloantigenic stimuli to determine the activation stimuli, anabolic activity, and accessory cells required for inducing their phenotypic and functional maturation. The kinetics of this differentiation process and the need for cell division will also be determined. Studies will be performed to determine whether the deficiency of the Leu-3+HB-10- T cell subpopulation in patients with X-linked agammaglobulinemia reflects a primary defect in T cell differentiation or a secondary aberration due to the absence of B cells. The immunoregulatory interactions of FACS-purified Leu-3+HB-10+ and Leu-3+HB-10- cells with Leu-2+ cells will be analyzed in B cell differentiation assays to determine the maturational stage of Leu-3+ suppressor-inducer cells and the characteristics of the Leu-3+ cells that interact with Leu-2+ contrasuppressor cells. The molecular weights, subunit structure, and interrelationship of the HB-10- and HB-11-reactive membrane molecules will be assessed by gel electrophoresis and sequential immunoprecipitation experiments. Finally, the phenotypic characteristics of Leu-3+ cells in patients with autoimmune or chronic inflammatory disorders as well as immunodeficiency diseases will be assessed. The definition of the ontogeny and functions of human immunoregulatory T cell subpopulations and the ability to assess post-thymic Th cell maturation in humans should enhance our understanding of the mechanisms by which quantitative or functional abnormalities of helper T cell subpopulations accompany or contribute to immunologial disorders.
|Uittenbogaart, C H; Schmidc, I; Kiertscher, S et al. (1996) Human thymocyte responsiveness to stem cell factor: synergy with interleukin-2 for the generation of NK/LAK cytotoxicity. Immunol Lett 52:45-52|
|Uittenbogaart, C H; Anisman, D J; Tary-Lehmann, M et al. (1994) The SCID mouse environment causes immunophenotypic changes in human immature T-cell lines. Int J Cancer 56:546-51|
|Bass, H Z; Yamashita, N; Clement, L T (1993) Heterogeneous mechanisms of human cytotoxic T lymphocyte generation. II. Differential effects of IL-6 on the helper cell-independent generation of CTL from CD8+ precursor subpopulations. J Immunol 151:2895-903|
|Yamashita, N; Nguyen, L; Fahey, J L et al. (1993) Phenotypic properties and cytotoxic functions of human CD8+ cells expressing the CD57 antigen. Nat Immun 12:79-91|
|Vollger, L W; Uittenbogaart, C H (1993) Interleukin-7 promotes the generation of phenotypically mature CD45RA positive human thymocytes in vitro. Cytokine 5:157-68|
|Bass, H Z; Yamashita, N; Clement, L T (1992) Heterogeneous mechanisms of human cytotoxic T lymphocyte generation. I. Differential helper cell requirement for the generation of cytotoxic effector cells from CD8+ precursor subpopulations. J Immunol 149:2489-95|
|Clement, L T (1992) Isoforms of the CD45 common leukocyte antigen family: markers for human T-cell differentiation. J Clin Immunol 12:1-10|
|Clement, L T (1991) Functional and phenotypic properties of 'naive' and 'memory' CD4+ T cells in the human. Immunol Res 10:189-95|
|Schmid, I; Uittenbogaart, C H; Giorgi, J V (1991) A gentle fixation and permeabilization method for combined cell surface and intracellular staining with improved precision in DNA quantification. Cytometry 12:279-85|
|Yamashita, N; Bullington, R; Clement, L T (1990) Equivalent helper functions of human ""naive"" and ""memory"" CD4+ T cells for the generation of alloreactive cytotoxic T lymphocytes. J Clin Immunol 10:237-46|
Showing the most recent 10 out of 20 publications