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Results for “CD5 Antigens”

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At least 19 recordsLinked to original sources
PubMed1993

Induction of CD5 antigen on human CD5- B cells by stimulation with Staphylococcus aureus Cowan strain I.

We have examined whether the CD5 phenotype could be induced on human B cell surfaces by the polyclonal B cell stimulator, Staphylococcus aureus Cowan strain I (SAC). Fresh tonsillar B cells were prepared by Percoll density gradient from E- cells. The proportion of CD5+ B cells in the 50/60% and 60/70% interface high-density fractions varied between 1.2 and 10.2% depending on the tonsil preparations when they were placed on the in vitro culture 12-60 h prior to flow cytometric analysis. The expression of CD5 antigen obviously increased in the presence of SAC (1:10(5) v/v). The percentage of CD5+ B cells varied from tonsil to tonsil, from 25.1 to 65.9% in a series of experiments. The CD5+ B cells were found both among CD23+CD25+CD71+ and CD23-CD25-CD71- B cells. The level of CD5 expression was related to the cell size enlargement. The addition of anti-CD5 antibody in the culture blocked the CD5 induction by SAC without interfering with the expression of other activation markers. A time-course study showed that CD5 antigen appeared to be induced on the cell surface during the G0 to G1 phase transition in the cell cycle. When CD5+ and CD5- B cells were separated by magnetic isolation, the CD5- B cells showed DNA synthesis to the stimulation by SAC and expressed CD5 antigen on their cell surface. These results suggest that human CD5- B cells can express the CD5 phenotype by stimulation with the polyclonal B cell stimulator, SAC.

Antibodies, Monoclonal↗
PubMed1999

[Expression of CD5 antigen in B and T cells from umbilical cord blood, from blood of healthy adults and patients with chronic lymphocytic B-cell leukemia (PBL-B)].

Antigen CD5 is the glycoprotein which belong to the scavenger receptor cysteine-rich family. Mainly there is on the T cells subpopulation. During fetal life B CD5+ cells are major subpopulation of B cells in the spleen, lymph nodes and there are also in the cord blood. In adult CD5+ cells are minor subpopulation (27%) of B cells from the peripheral blood. CD5 there are on chronic lymphocyte leukaemia B cells (B-CLL) also. Usually expression CD5 on B-CLL cells associated with weak or lack expression of the surface immunoglobulins and CD79 beta, CD20, CD22, CD21 (CR-2), CD35 (CR-1) antigens. It appeared interesting to compare the expression of CD5 antigen (the mean fluorescence intensity--MFI of CD5) on B cells from the cord blood, adults peripheral blood and B-CLL patients. MFI of CD5 on B and T cells were also compared in each groups. MFI of CD 19 was studied too. Lymphocytes from the cord blood (11 assays), adult peripheral blood of healthy volunteers (18 assays) and the peripheral blood of no treated patients with B-CLL (56 assays) were studied. The immunological phenotype of lymphocytes was evaluated with the monoclonal antibodies anti-CD5 and anti-CD19 by the flow cytometry method. We have demonstrated that MFI of CD5 on B cells from patients with B-CLL was strongest and weakest from normal individuals. MFI of CD5 on T cells from patients with B-CLL is stronger in comparison to healthy volunteers. MFI of CD19 is weakest on cells from patients with B-CLL and strongest in normal individuals. On the basis of the our results and other medical papers we suggest on the one hand that biology of B-CLL depend on deficit antigens specific for B cells lines on the other hand depend on overexpression of CD5 antigens on leukaemic B and T cells also.

Adult↗
PubMed1990

Up-regulation and down-regulation of cell surface and mRNA expression of CD5 antigen by various humoral factors on murine 70Z/3 pre-B cell leukemia cell line: IL-4 down-regulates CD5 antigen expression.

CD5, a pan-T cell antigen, is expressed on a minor subset of normal B lymphocytes and on cells of most B lineage tumors or transformed B cells in both man and animal models. In the present study, the effects of various humoral factors on CD5 expression by cells of a subcloned 70Z/3 murine pre-B leukemia cell line were investigated. Among the humoral factors studied, only LPS up-regulated CD5 expression on 70Z/3 cells (three- to fourfold) in a dose-dependent manner. However, this up-regulatory effect of LPS was not observed when cells were cultured in serum-free medium. NZB-serum factor (NZB-SF), a cytokine we have identified and shown to enhance the maturation and proliferation of immature B cells, synergistically enhanced CD5 expression in the presence of suboptimal doses of LPS. IL-4 down-regulated CD5 expression by 70Z/3 cells induced by LPS or LPS plus NZB-SF in a dose-dependent manner. IL-4 also suppressed spontaneous CD5 expression by 70Z/3 cells. No other cytokine tested showed an inhibitory effect. LPS, IFN-gamma, NZB-SF, and IL-1 enhanced sIg expression on 70Z/3 cells and their action on sIg expression was not inhibited by IL-4. Thus, the down-regulatory action of IL-4 on CD5 expression appeared specific for this antigen. IFN-gamma, which inhibits IL-4 induced CD23 and DR expression on B cells, does not abolish the down-regulatory action of IL-4 on CD5 expression by 70Z/3 cells. Changes in mRNA levels on coding CD5 were also examined following the incubation of 70Z/3 cells (24 hr) in the presence of humoral factors which can influence CD5 Ag expression. The levels of mRNA for CD5 Ag were moderately increased in the presence of LPS and NZB-SF. IL-4 appeared to suppress the actions of NZB-SF and LPS at least in part by reducing the levels of mRNA encoding CD5.

Animals↗
PubMed1992

Evidence for an association between the T cell receptor/CD3 antigen complex and the CD5 antigen in human T lymphocytes.

In this work we report that CD5, a T cell accessory activation antigen and receptor for the B cell surface protein CD72, is associated with the T cell antigen receptor (TcR)/CD3 complex in human T lymphocytes. In vitro phosphorylation of either CD3 or CD5 immunoprecipitates prepared from CD3-stimulated Jurkat and peripheral blood T cells in the presence of the detergent polyoxyethelene 10 oleyl ether (Brij96) showed, unexpectedly, an identical pattern of five phosphopolypeptides of 70, 59, 56, 21 and 18 kDa, respectively. Peptide mapping of the five bands demonstrated that the same protein kinase substrates co-precipitated with both CD3 and CD5 and that the majority of the protein phosphorylation occurred on tyrosine residues. These data suggested that the TcR/CD3 complex and and the CD5 antigen might be associated in T cells. Evidence to support this hypothesis was obtained from analysis of immunoprecipitates prepared from surface-iodinated T cells. Bands characteristic of the TcR and CD3 antigens were identified in CD5 immunoprecipitates and conversely, CD5 was identified in CD3 immunoprecipitates. Conformation that CD3 and CD5 co-precipitated in the presence of Brij96 was obtained by Western blotting. Quantitative immunodepletion demonstrated that between 10%-20% of cell surface CD5 was associated with the TcR/CD3 complex in Brij96 detergent lysates of human T cells and, furthermore, that this association was independent of T cell activation. The association of these two receptors provides a possible physical basis for the accessory role of the CD5 antigen in T cell activation.

Antigens, CD↗
PubMed1998

Intravascular large B-cell lymphoma: the CD5 antigen is expressed by a subset of cases.

The CD5 antigen is a T-cell associated marker that is also usually expressed by two B-cell neoplasms, chronic lymphocytic leukemia/small lymphocytic lymphoma and mantle cell lymphoma. We observed CD5 antigen expression in a subset of cases of intravascular large B-cell lymphoma (IVLBL), and we report here five cases. The patients, two men and three women, ranged in age from 59 to 81 years. Biopsy specimens were obtained from kidney, lung, bone marrow, abdominal wall, and neck, the latter involving a lymphangioma. All of the cases had histologic features typical of IVLBL, with large and atypical lymphoid cells located predominantly within blood vessels. Immunohistochemical studies performed using routinely fixed, paraffin-embedded tissue sections showed that the neoplastic cells were B cells, positive for the CD20 antigen and negative for the CD3 or CD43 antigens. All cases were also positive for the CD5 antigen. One case had an immunoglobulin heavy chain gene rearrangement shown by using a polymerase chain reaction method. The finding of CD5 antigen expression in a subset of IVLBL cases adds to other evidence in the literature suggesting that IVLBL is a heterogeneous entity. We considered the possibility that these cases were related to or represented unusual histologic forms of transformation from either chronic lymphocytic leukemia/small lymphocytic lymphoma or mantle cell lymphoma. All of the cases, however, were negative for the CD23 antigen and cyclin D1 (bcl-1) protein, which is evidence against this interpretation. The biologic significance of CD5 antigen expression in cases of IVLBL is uncertain. These neoplasms might arise from a separate lineage of CD5-positive B cells or from a specific, early stage of B-cell differentiation. Alternatively, some investigators have suggested that CD5 antigen expression by B cells is a marker of activation.

Aged↗
PubMed1989

Cell surface antigen CD5 is a marker for activated human B cells.

A minor subset of B cells which in vivo express the surface antigen CD5, has attracted much attention because of its involvement in autoimmune responses. On the basis of observations showing self-renewal capacity of such cells in mice and also the absence of a substantial change of CD5 phenotype during B cell activation in vitro, the CD5+ B cells are now generally considered to represent a separate cell lineage. In the present study, CD5- B cells were isolated by cell sorter and then stimulated in vitro with mutagenized EL4 thymoma cells in the presence of T cell supernatant. About 70% of the B cells were CD5+ after 3 days. Thus, the CD5 antigen behaves as a B cell activation marker. In our system we found that the frequency of rheumatoid factor-producing B cells was on average three times higher in CD5+ than in CD5- B cells isolated ex vivo from human peripheral blood. Most likely this reflects frequent activation of such autoreactive B cells in vivo.

Antibody Formation↗
PubMed1994

Discrimination between two subsets of porcine CD8+ cytolytic T lymphocytes by the expression of CD5 antigen.

Previous work has revealed striking differences in the peripheral T-lymphocyte compartments of swine compared to other species. The key difference is the existence of four T-lymphocyte subpopulations defined by their CD4/CD8 expression. Besides this difference in the CD4/CD8 antigen expression, we report here another unusual antigen distribution on porcine extrathymic T lymphocytes: the expression of the 63,000 MW CD5 antigen. In porcine thymus the CD5 antigen shows a biphasic antigen density, whereas the majority of thymocytes are characterized by an intermediate CD5 expression. In the extrathymic T-lymphocyte compartment, CD5 also shows a heterogeneous antigen distribution as defined by three subsets: CD5high, CD5dim and CD5- T lymphocytes. Analyses of the CD5 expression on the four CD4/CD8-defined peripheral T-cell subpopulations revealed that all CD4+ T lymphocytes, CD4+ CD8+ as well as CD4+ CD8- T lymphocytes, belonged to the subset with high CD5 antigen density. The CD4- CD8- subpopulation, containing in the majority T-cell receptor (TcR) gamma delta T lymphocytes, was characterized by dim CD5 expression. The most notable difference was the division of the CD4- CD8+ cytolytic T-lymphocyte subpopulation into two CD5-defined subsets: CD4- CD5- CD8+ lymphocytes with spontaneous cytolytic activity against tumour cells, and CD4- CD5+ CD8+ T lymphocytes with major histocompatibility complex (MHC)-restricted cytolytic function. Thus, the porcine CD5 antigen is an important marker to discriminate between CD5- CD8+ natural killer (NK) cells and CD5+ CD8+ progenitors of MHC-restricted cytolytic T lymphocytes.

Animals↗
PubMed1988

A requirement for the CD5 antigen in T cell activation.

Treatment of adult rats with a monoclonal antibody specific for the CD5 antigen led to a dramatic reduction in the number of CD5+ cells. However, a substantial number of T cells remained as assessed by other T cell-specific antibodies. These CD5- T cells did not proliferate in response to alloantigen or mitogenic stimulation, did not generate cytotoxic T lymphocytes in vitro, and did not induce graft-vs.-host disease when injected into susceptible recipients in vivo. Re-expression of the CD5 antigen occurred when CD5- T cells were placed in an environment devoid of the anti-CD5 antibody. Re-expression of the antigen was followed by return of the T cell proliferative responses. While CD5- T cells could not proliferate in response to alloantigen they could produce interleukin 2 following a short pulse with the T cell mitogen concanavalin A. However, T cell proliferative or cytotoxic responses could not be rescued by the addition of an exogenous source of interleukin 2. We conclude that the CD5 antigen appears to be required for proliferation of resting T cells.

Animals↗
PubMed1989

In vivo and in vitro phosphorylation of murine lymphocyte differentiation antigen CD5.

Ly-1, the murine lymphocyte differentiation antigen CD5, is phosphorylated constitutively in vivo. This phosphorylation is enhanced by phorbol 12-myristate 13-acetate (PMA) treatment, but not by concanavalin A, Ca2+ ionophore or dibutyryl cAMP. Prolonged PMA treatment abolished PMA-induced Ly-1 phosphorylation but not constitutive phosphorylation, suggesting that protein kinase C (PKC) is responsible for this enhanced phosphorylation, but not the basal phosphorylation of Ly-1. Ly-1 is phosphorylated by PKC added to membranes, further supporting a role for protein kinase C in the in vivo phosphorylation of Ly-1.

Amino Acids↗
PubMed1998

Detection of CD5 antigen on B cell lymphomas in fixed, paraffin embedded tissues using signal amplification by catalyzed reporter deposition.

CD5 surface antigen is expressed on some categories of B cell lymphomas. The detection of CD5 coexpression on malignant B cell infiltrates, particularly in small biopsy specimens, is useful in distinguishing between small lymphocytic lymphoma, mantle cell lymphoma, low grade marginal zone B cell lymphoma, and follicular small cleaved cell lymphoma. However, conflicting results have been reported with regard to the detection of CD5 antigen expression on B cell non-Hodgkin's lymphomas (B-NHLs) in fixed, paraffin embedded tissues using routine immunohistochemical (IHC) staining techniques. We used catalyzed reporter deposition (CARD) as a strategy to amplify the IHC signal and consequently increase the sensitivity of antigen detection. CARD improved detection of CD5 antigen without sacrificing specificity of the test. In our study, virtually all malignant B-NHLs with CD5 antigen expression showed strong immunoreactivity for a commercially available anti-CD5 monoclonal antibody using CARD, whereas the majority of the same lymphomas did not label for CD5 using routine IHC without CARD amplification. The concordance between CD5 antigen detection by immunophenotyping of fresh or frozen tissues and immunostaining with CARD amplification on paraffin fixed tissue sections was 100%. It appears that this method can be applied in the diagnostic evaluation of B-NHLs or in other situations that a weak antigen signal is present.

Biotin↗
PubMed1994

Modulation of the expression of CD5 antigen on the surface of human peripheral B lymphocytes.

In this study, we investigated the expression of CD5 molecules on the surface of mature human peripheral B lymphocytes. Human CD5+ B cells were isolated from tonsils and peripheral blood. Their terminal differentiation into plasma cells was induced with IL-2. In the presence of this lymphokine, a subset of CD5+ B cells ceased to express CD5 proteins on their surface. When CD5+ B cells and non-B cells were removed from the suspension. CD5 antigens were spontaneously reexpressed on the surface of CD5- B cells. This suggests that the CD5- phenotype of a subset of B cells in these suspensions resulted from pressure(s) exerted on them by the other cellular components of the suspensions. B cells which have reexpressed membrane CD5 in the absence of CD5+ B cells and non-B cells retained their ability to reprogress to CD5- phenotype and to undergo terminal differentiation into plasma cells when stimulated with IL-2. A short exposure (4 hr) of CD5- B cells to 5 nM IL-2 resulted in the loss of their capability to spontaneously reexpress surface CD5 in the absence of other lymphoid cells. Taken together, these data suggest that the expression of CD5 antigens on B cell membrane is governed by a network-type balance between all cellular compartments within the suspension. Fluctuations of this equilibrium results in the shuttling of B cells between CD5+ and CD5+ phenotypes until they become irreversibly engaged in the terminal differentiation pathway. The interconversion CD5+<==>CD5- on B cell membrane does not argue for CD5 molecule as the marker of a distinct B cell lineage.

Antigens, CD↗
PubMed1986

Monoclonal antibodies to the CD5 antigen can provide the necessary second signal for activation of isolated resting T cells by solid-phase-bound OKT3.

Activation of human peripheral blood T cells by the anti-CD3 antibody OKT3 has been shown to require not only cross-linking of CD3 molecules with multimeric binding of the Fc part of OKT3 to a solid support, but also a second accessory cell-provided signal. Accordingly, measurement of T cell activation in cultures of highly enriched T cells with solid-phase-bound OKT3 can be used to investigate whether other agents can replace accessory cells. In this study we examined the capacity of anti-CD5 monoclonal antibodies to provide the additional activation signal. Resting T cells were prepared by isolating E rosette-positive cells, by removing OKM1(+) and HLA-DR(+) cells by panning, and by subsequent treatment of the cells with L-leucine methyl ester to kill remaining monocytes. These T cells were unresponsive to phytohemagglutinin (PHA) or to solid-phase-bound OKT3. However, when cultured in the presence of an anti-CD5 monoclonal antibody (anti-Leu-1, OKT1, or anti-T1), a proliferative response to solid-phase-bound OKT3 (but not to soluble OKT3 or to PHA) was observed. Anti-CD5 had no functional effect by itself, but in association with solid-phase-bound OKT3 it enhanced IL 2 receptor expression and IL 2 production and it initiated T cell proliferation. T cell proliferation under these conditions could be inhibited by an IL 2 receptor blocking antibody anti-Tac, thus confirming that anti-CD5 provides the second signal for an IL 2-dependent pathway of T cell proliferation. Preincubation of T cells with anti-Leu-1 or OKT1 resulted in complete loss of CD5 antigenicity, and such CD5 modulation was sufficient to induce a proliferative response to solid-phase-bound OKT3. It is concluded that in T cell activation by solid-phase-bound OKT3 the necessary additional signal can be provided by modulation of the CD5 antigen with an anti-CD5 antibody. CD5 therefore appears to be a positive signal receptor on the T cell membrane, whose physiologic ligand still has to be determined.

Antibodies, Monoclonal↗
PubMed1998

Structural analysis of the CD5 antigen--expression, disulphide bond analysis and physical characterisation of CD5 scavenger receptor superfamily domain 1.

CD5 is a type-I transmembrane glycoprotein found on thymocytes, T-cells and a subset of B-cells. The extracellular region consists of three domains belonging to the scavenger receptor cysteine-rich (SRCR) superfamily, for which no three-dimensional structure has been obtained. Recombinant soluble CD5 domain 1 (CD5d1), the N-terminal SRCR domain, has been expressed in both chinese hamster ovary (CHO) cells and Pichia pastoris. CD5d1 was shown to be correctly folded by binding to the CD5 monoclonal antibody Leul. Circular dichroism and NMR analyses indicate that CD5d1 has a high beta-sheet content. CD5d1 from both CHO cells and P. pastoris have very similar properties. The disulphide bonding pattern was determined and is consistent with that found for the group-A SRCR domain of type-1 macrophage scavenger receptor and MARCO, the macrophage receptor with collagenous structure. Observations have been made of the role of glycosylation of CD5. P. pastoris expression provides large quantities of correctly folded recombinant CD5d1 for multidimensional NMR and for X-ray crystallographic studies. The whole extracellular region of CD5, expressed as a chimaera with rat CD4 domains 3 and 4 (cCD5d1-3-CD4d3+4), was studied by electron microscopy and carbohydrate analysis to gain an overview of the structure of the extracellular portion of intact CD5. Carbohydrate analysis identified N-linked glycans on CD5 domains 1 and 2, and sialylated O-linked glycans on the linker peptide between domains 1 and 2. Electron microscopy and carbohydrate analysis together suggest that the extracellular region of CD5 forms a rod-like structure with domain 1 distal from the cell surface and separated from domains 2 and 3 by an O-glycosylated peptide linker region.

Amino Acid Sequence↗
PubMed1995

A CD3+CD8+ T cell population lacking CD5 antigen expression is expanded in peripheral blood of human immunodeficiency virus-infected patients.

In this study we analyzed the behavior of a CD3+ T cell subpopulation lacking CD5 antigen expression in PBMC from HIV-1-infected patients. CD3+CD5- lymphocytes were greatly increased in peripheral blood of HIV-1+ patients, accounting for 20.6 +/- 9.9% of the total CD3+ cells, compared to seronegative individuals (5.5 +/- 3.2%). In both seropositive patients and controls, CD3+CD5- cells belonged to the CD8+ compartment; they were nonactivated, TCR alpha/beta+, naive lymphocytes, and in seronegative individuals preferentially expressed NK cell-associated markers, such as CD11b, CD16, CD56, and CD57. The phenotypic profile of this subset was slightly different in seropositive patients; while TCR expression and CD45RA/RO profile were comparable, CD11b and CD16 expression was lower compared to control figures, while CD56 expression was not changed, and CD57 expression was enhanced. Functional analysis of enriched CD3+CD8+CD5- cells showed an impaired ability to proliferate in response to mitogenic and antigenic stimuli; despite their NK-like phenotype, CD3+CD8+CD5- cells did not exert any NK cytotoxic activity, and only a lectin-dependent cytotoxic potential could be evidenced in this population. These results describe a novel alteration in the lymphocytes phenotypic profile during HIV-1 infection, involving a "transitional" population, which shares some properties of the T and of the NK cell lineage.

Biomarkers↗
PubMed1991

Autoantibody-associated cross-reactive idiotype-bearing human B lymphocytes: distribution and characterization, including Ig VH gene and CD5 antigen expression.

Monoclonal antibodies (MoAbs) specific for autoantibody associated cross-reactive idiotypes (CRIs) frequently recognize the Igs of neoplastic B cells in patients with chronic lymphocytic leukemia (CLL) and/or Waldenstrom's macroglobulinemia. Very little is known regarding the normal B cells expressing CRIs (CRI-positive B cells). Using a variety of MoAbs against CRIs we investigated the distribution and topographic localization of CRI-positive B cells in normal adult human lymphoid tissues. We found that CRI-positive B cells represent a significant B-cell subpopulation expressing surface IgM (greater than 90%), IgG (approximately 5%), or IgA (approximately 2%). CRI-positive B cells are homogeneously distributed throughout all lymphoid tissues, accounting for 10% to 15% of all B lymphocytes, with the exception of the thymus, in which they represent the predominant B cell population. Immunophenotypic studies showed (1) that a small subpopulation (3.7% +/- 0.8%) of CRI-positive B cells are activated in vivo, based on CD25 and CD38 antigen expression; and (2) that approximately 50% of CRI-positive B cells express the 67-Kd pan-T-lymphocyte CD5 antigen, suggesting that the CRI-positive B-cell subset and the recently described CD5-positive B-cell subset are closely related. This hypothesis is supported by the fact that CRI-positive B cells produce oligo or polyreactive Igs, which are a characteristic feature of CD5-positive B cells, and also by the fact that both B-cell subpopulations appear to use similar and restricted Ig VH gene family members.

Antibodies, Monoclonal↗