Soluble CD23 (Fc epsilon RII) and interleukin 1 synergistically induce early human thymocyte maturation.

Abstract

During development, lymphoid stem cells migrate into the thymic rudiment where they differentiate into functionally mature T lymphocytes (1). Among human thymocytes, CD7 + CD2 -CD3 -CD4 -CD8 -(referred hereafter as CD7') cells represent the earliest identifiable step (2-4) . In vitro, these precursors were able to acquire mature T cell antigens (3, 4), but cellular interactions and cytokines necessary for this process are poorly understood. We have previously reported that enriched populations of B lymphocytes from blood produce factors (3, 5) that promote in vitro development of blood-and bone marrow-derived CD7 + CD2 -precursors. Comparing the biochemical characteristics of this B cell-derived activity (3) to known B cell-derived molecules, we found its striking homology to soluble CD23 (sCD23 ; sFcERII) (6, 7) . Using recombinant sCD23 (rsCD23) (7), we then assayed the effect of this molecule alone or with rIL-1 and/or rIL-2 on purified CD7 + thymic precursors . Our results provide direct evidence that sCD23 and rIL-1 synergistically induce CD7 + prothymocytes maturation into CD2'CD3'TCRa//3+ CD4 + and/or CD8 + cells that respond to CD2 triggering and rIL-2.

Soluble CD23 levels are elevated in the serum of patients with primary Sjögren's syndrome and systemic lupus erythematosus

“…It has recently been reported that a combination of IL-1 and sCD23 induces thymocyte maturation [19]. Furthermore, in the presence of IL-1, sCD23 inhibits apoptosis of germinal centre B cells by the induction of the bcl-2 gene [20].…”

CD23 Isoforms in Murine T and B Lymphocytes

“…23]. in the progression of B lymphocytes from GO through G1 [23,24], and in the differentiation of both early human myeloid precursors and prothymocytes to thymocytes [25][26][27][28].…”

Elevation of Soluble CD23 in Serum from Patients with Blood Eosinophilia

“…FceRII/CD23can be cleaved from the surface of B lymphocytes and released in soluble frag ments (sCD23) with different molecular weights: 37, 33 and 25 kD [3], In addition to their IgE-binding function, CD23 and sCD23 exert pleiotropic activities. Soluble CD23 isoforms I his work was |>crformed jointlv in Unité Mixte INSERM UI67-CNRS f'24 and in the Service d'immunologie du Centre Hospitalier et Universitaire de Lille. are involved in the regulation of IgE production by B cells [3] and in the differentiation of early thymocytes, in syn ergy with IL-1 [4], Recombinant sCD23 can also promote the survival and differentiation of germinal center B cells, and the growth and differentiation of early myeloid pre cursor cells [5], Several studies have demonstrated that the IgE-binding region is confined to the carboxyterminal lectin homology domain [6], Flowevcr, it has recently been shown that the cytokine effects of CD23 were medi ated by a motif distinct from the IgE-binding site [7].…”