Open AccessExpression of CD28 by Bone Marrow Stromal Cells and Its Involvement in B Lymphopoiesis
Author(s) -
Kirstin Gray Parkin,
Robert P. Stephan,
Ron Gran Apilado,
Deborah A. Lill-Elghanian,
Kelvin P. Lee,
Bhaskar Saha,
Pamela L. Witte
Publication year - 2002
Publication title -
the journal of immunology/the journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.737
H-Index - 372
eISSN - 1550-6606
pISSN - 0022-1767
DOI - 10.4049/jimmunol.169.5.2292
Subject(s) - stromal cell , lymph node stromal cell , lymphopoiesis , cd28 , bone marrow , haematopoiesis , biology , b cell , cd80 , t cell , cd86 , cd40 , microbiology and biotechnology , cd19 , flow cytometry , immune system , immunology , chemistry , stem cell , cancer research , cytotoxic t cell , in vitro , antibody , biochemistry
Young mice lacking CD28 have normal numbers of peripheral B cells; however, abnormalities exist in the humoral immune response that may result from an intrinsic defect in the B cells. The goal of this study was to assess whether CD28 could be involved in the development of B cells. CD28 mRNA was detected preferentially in the fraction of bone marrow enriched for stromal cells. Flow cytometry and RT-PCR analysis demonstrated that CD28 was also expressed by primary-cultured stromal cells that supported B lymphopoiesis. Confocal microscopy revealed that in the presence of B-lineage cells, CD28 was localized at the contact interface between B cell precursors and stromal cells. In addition, CD80 was detected on 2-6% of freshly isolated pro- and pre-B cells, and IL-7 stimulation led to induction of CD86 on 15-20% of pro- and pre-B cells. We also observed that stromal cell-dependent production of B-lineage cells in vitro was greater on stromal cells that lacked CD28. Finally, the frequencies of B-lineage precursors in the marrow from young (4- to 8-wk-old) CD28(-/-) mice were similar to those in wild-type mice; however, older CD28(-/-) mice (15-19 mo old) exhibited a 30% decrease in pro-B cells and a 50% decrease in pre-B cells vs age-matched controls. Our results suggest that CD28 on bone marrow stromal cells participates in stromal-dependent regulation of B-lineage cells in the bone marrow. The localization of CD28 at the stromal cell:B cell precursor interface suggests that molecules important for T cell:B cell interactions in the periphery may also participate in stromal cell:B cell precursor interactions in the bone marrow.