This proposal addresses abnormal development of B cells and B cell precursors in murine models of systemic lupus erythematosus (SLE). We hypothesize that NZB and (NZB x NZW)F1 autoimmune mice undergo a progressive decline in both the number of B cell precursors detected within the bone marrow and in the mitotic activity of these precursor cells. This may result from either 1) failure of B cell precursors respond to developmental signals: 2) failure of the bone marrow stroma to adequately support B lineage proliferation and development; or 3) abnormal down-regulation of B lineage precursors via T cells and/or regulatory Ly1/Mac1 lineage B cells. In order to test this hypothesis, we will: A) Use vincristine induced metaphase arrest (stathmokinetic) assays to assess the mitotic activity of B cell precursor cells in both normal and NZ autoimmune bone marrow as a function of age. B) Define whether the mechanisms responsible for defective B lymphopoiesis in NZ mice operate at the precursor cell level or upon the non-lymphoid stroma necessary for the support of B lineage cell proliferation and differentiation. These experiments will use in vitro short term and long term bone marrow cell culture systems to allow differentiation of NZ B lineage cells with normal bone marrow stroma and vice versa. C) Determine the capacity of NZ bone marrow stromal cells to secrete cytokines, including IL-7, necessary for maintenance of pre-B cell growth. These experiments will use bioassays and also will quantitate ILl-7 mRNA levels in normal vs. NZ stroma. D) Evaluate the capacity of NZ T cells to secrete excessive quantities of lymphokines which inhibit proliferation of B lineage precursor cells. Specific bioassays for both IL-2 and IL-4 will be performed since these lymphokines may influence B lineage cell development and growth. E) Assess the capacity of NZ Ly1/Mac1 bearing B cells within the bone marrow to down-regulate the proliferation and generative capacity of bone marrow B lineage cells. These experiments will use in vivo model systems in which NZ Ly1/Mac1 B cells will be expanded in normal recipients (e.g., [NZB x BALB/c]F1 or immunodeficient SCID mice). The capacity of normal B lineage precursor cells to proliferate and develop in the presence of NZ LY1/Mac1 B cells will then be determined. With this experimental plan, we will test the above hypothesis and establish the mechanisms by which B lineage cell development in NZ mice is decreased and the possible role of this defect in establishment of lymphocyte autoreactivity.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
2R01AI023350-04A1
Application #
3135332
Study Section
Immunological Sciences Study Section (IMS)
Project Start
1986-09-30
Project End
1993-06-30
Budget Start
1990-07-01
Budget End
1991-06-30
Support Year
4
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Miami School of Medicine
Department
Type
Schools of Medicine
DUNS #
City
Miami
State
FL
Country
United States
Zip Code
33146
Merchant, M S; Garvy, B A; Riley, R L (1995) B220- bone marrow progenitor cells from New Zealand black autoimmune mice exhibit an age-associated decline in Pre-B and B-cell generation. Blood 85:1850-7
Elia, J M; Hamilton, B L; Riley, R L (1995) IL-10 inhibits IL-7-mediated murine pre-B cell growth in vitro. Exp Hematol 23:323-7
Garvy, B A; Riley, R L (1994) IFN-gamma abrogates IL-7-dependent proliferation in pre-B cells, coinciding with onset of apoptosis. Immunology 81:381-8
Riley, R L; Kruger, M G; Landa, B et al. (1991) B cells in autoimmune (NZB x NZW)F1 mice show altered IgG isotype switching upon T cell-dependent antigenic stimulation in vitro. Clin Immunol Immunopathol 58:33-45
Riley, R L; Kruger, M G; Elia, J (1991) B cell precursors are decreased in senescent BALB/c mice, but retain normal mitotic activity in vivo and in vitro. Clin Immunol Immunopathol 59:301-13
Kruger, M G; Riley, R L (1990) The age-dependent loss of bone marrow B cell precursors in autoimmune NZ mice results from decreased mitotic activity, but not from inherent stromal cell defects. J Immunol 144:103-10
Kruger, M G; Riley, R L; Riley, E A et al. (1990) Bone marrow stromal cells modulate both kappa light chain and Ly1 antigen expression on Ly1+ pre-B cell lines in vitro. Blood 76:383-92
Pinto, V B; Riley, R L; Peacock, J S (1989) Effects of interleukin 4 on neonatal B lymphocyte tolerance. Biochem Biophys Res Commun 164:199-204
Riley, R L; Kruger, M G; Riley, E A (1989) Abnormal development of B cells and B cell progenitors in autoimmune (NZB x NZW)F1 mice. Clin Immunol Immunopathol 51:372-85