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 CD4+ T cells. These studies are designed to test the hypothesis that the immunoregulatory functions of CD4+ cells are performed by distinct subsets that are recognizable by the presence or absence of membrane antigens variably expressed at sequential stages of post- thymic differentiation. We further hypothesize that the appearance or loss of these antigens is regulated by lymphokines, particularly IL-4 and IL-2.
Our specific aims are to determine whether immature CD4+CD45R+ """"""""virgin"""""""" T cells can be induced to differentiate in vitro into two distinct subsets of CD45R""""""""-memory"""""""" T cells which have either helper or suppressor-inducer functions, and which can be distinguished by the absence or presence, respectively, of Leu 8 antigen expression. Subsets of CD4+ cells purified by panning or fluorescence activated cell sorting will be activated under different conditions to determine the induction stimuli and lymphokines required for their phenotypic and functional maturation. The kinetics and specificity of these phenotypic changes will be determined using three-color flow cytometry techniques. Functional correlation will be obtained by examining the immunoregulatory capabilities of the evolving CD4+ subsets at serial intervals during their in vitro maturation. Findings from these studies will then be used to analyze and interpret the pattern of CD4+ cell repopulation after different types of bone marrow transplantation, with the goal of determining the role of abnormal CD4+ cell differentiation in post-transplant immune deficiency. Studies characterizing the generation of CD3+CD45R+ thymocytes by IL-4 will also be performed, using an in vitro culture system and three-color flow cytometry. In addition, the relationship of these CD45R+ thymocytes to a population of IL-4- responsive cells uniquely found in neonatal cord blood will be investigated. Finally, the maturation and function of CD4+ calls in patients with immunodeficiency or immunoregulatory diseases will be assessed. Definition of the ontogeny and functions of immunoregulatory CD4+ subpopulations and the ability to assess post-thymic CD4+ cell maturation in humans should enhance our understanding of the mechanisms by which quantitative or functional abnormalities of CD4+ subsets accompany or contribute to immunological disorders.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
7R01CA042735-09
Application #
2090904
Study Section
Project Start
1986-03-01
Project End
1996-03-31
Budget Start
1995-01-13
Budget End
1996-03-31
Support Year
9
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Children's Mercy Hosp (Kansas City, MO)
Department
Type
DUNS #
City
Kansas City
State
MO
Country
United States
Zip Code
64108
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
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 (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
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

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