In rabbits nearly all B lymphocytes express the glycoprotein CD5, in contrast to mice and humans, where only a small proportion of B cells express this molecule (Raman, C., and K.L. Knight. 1992. J. Immunol. 149:3858-3864). CD5+ B cells appear to develop early in ontogeny and be maintained throughout life by self-renewal. The function of CD5 on B cells is still unknown. We showed earlier that "...

In contrast to highly mutated follicular lymphomas and multiple myelomas, chronic lymphocytic leukemias (CLLs) frequently express VH genes in germline configuration. It is currently unclear whether this difference is related to the expression of CD5 or to the differentiation stage of the B cell when malignant transformation occurs. We have studied the VH sequence of 11 cases of CD5- B-CLL to ad...

BACKGROUND Several biomarkers indicating poor prognosis have been reassessed in patients receiving rituximab combination chemotherapy for diffuse large B-cell lymphoma (DLBCL). However, few studies have investigated outcome in relation to a combination of these biomarkers. In addition, no large-scale studies have reassessed the outcome of patients with CD5-positive DLBCL treated with rituximab....

B-cell maturation from hematogones to mature B cells in bone marrow exhibits a consistent, complex spectrum of sequential antigen expression. CD5 expression, however, has not been characterized. We studied the dynamics of CD5 expression on developing B cells by 4-color flow cytometry in 32 patients, aged 9 months to 63 years, with hematogone hyperplasia (>3.5% of total events). The mean percent...

CD5 and CD6 are closely related lymphocyte surface receptors of the scavenger receptor cysteine-rich superfamily, which show highly homologous extracellular regions but little conserved cytoplasmic tails. Both molecules are expressed on the same lymphocyte populations (thymocytes, mature T cells, and B1a cells) and share similar co-stimulatory properties on mature T cells. Although several work...

Blood mononuclear cells from 540 newly diagnosed, unselected patients with B-cell chronic lymphocytic leukemia (CLL) were examined by immunofluorescence flow cytometry for a panel of surface membrane markers, including IgM and IgD, the monoclonal antibodies anti-CD3, -5, -20, -21, -22, -FMC7, and, for the final 125 patients, anti-CD23. There were 503 CD5+ and 37 CD5- cases. In the CD5+ cases, t...

When T cells are activated by the T-cell antigen receptor, a number of cellular proteins are phosphorylated on tyrosine. We investigated whether any of these proteins were present on the surface of activated T cells. Using the human leukemic T-cell line Jurkat and normal peripheral blood lymphocytes, we identified a 67-kDa cell surface glycoprotein in anti-phosphotyrosine immunoprecipitates, af...

PURPOSE CD5 is a T cell marker, aberrantly express in B cell chronic lymphocytic leukemia (B-CLL) and mantle cell lymphoma (MCL). Other chronic B cell malignancies including hairy cell leukemia (HCL) and B cell prolymphocytic leukemia (B-PLL) are CD5 negative or express this antigen in a weak way. In this study, CD5 expression was investigated in leukemic cells from 42 patients with chronic B c...

CD5 is a cell surface receptor that negatively regulates B cell function, but whose relationship to the immunoreceptor tyrosine-based inhibitory motif (ITIM) family of B cell inhibitory receptors is unclear. Using Fcgamma type IIB receptor-CD5 chimeras encompassing the cytoplasmic domain of CD5, we previously showed that a particular region of the molecule containing two tyrosine residues, Y429...

CD5 is a lymphocyte surface glycoprotein with a long cytoplasmic domain suitable for phosphorylation and signal transduction, which is involved in the modulation of Ag-specific receptor-mediated activation and differentiation signals. In this study, we use Jurkat T cell transfectants of CD5 cytoplasmic tail mutants to reveal phosphorylation sites relevant to signal transduction. Our results sho...