CD150 association with either the SH2-containing inositol phosphatase or the SH2-containing protein tyrosine phosphatase is regulated by the adaptor protein SH2D1A.

CD150 (SLAM/IPO-3) is a cell surface receptor that, like the B cell receptor, CD40, and CD95, can transmit positive or negative signals. CD150 can associate with the SH2-containing inositol phosphatase (SHIP), the SH2-containing protein tyrosine phosphatase (SHP-2), and the adaptor protein SH2 domain protein 1A (SH2D1A/DSHP/SAP, also called Duncan's disease SH2-protein (DSHP) or SLAM-associated protein (SAP)). Mutations in SH2D1A are found in X-linked lymphoproliferative syndrome and non-Hodgkin's lymphomas. Here we report that SH2D1A is expressed in tonsillar B cells and in some B lymphoblastoid cell lines, where CD150 coprecipitates with SH2D1A and SHIP. However, in SH2D1A-negative B cell lines, including B cell lines from X-linked lymphoproliferative syndrome patients, CD150 associates only with SHP-2. SH2D1A protein levels are up-regulated by CD40 cross-linking and down-regulated by B cell receptor ligation. Using GST-fusion proteins with single replacements of tyrosine at Y269F, Y281F, Y307F, or Y327F in the CD150 cytoplasmic tail, we found that the same phosphorylated Y281 and Y327 are essential for both SHP-2 and SHIP binding. The presence of SH2D1A facilitates binding of SHIP to CD150. Apparently, SH2D1A may function as a regulator of alternative interactions of CD150 with SHP-2 or SHIP via a novel TxYxxV/I motif (immunoreceptor tyrosine-based switch motif (ITSM)). Multiple sequence alignments revealed the presence of this TxYxxV/I motif not only in CD2 subfamily members but also in the cytoplasmic domains of the members of the SHP-2 substrate 1, sialic acid-binding Ig-like lectin, carcinoembryonic Ag, and leukocyte-inhibitory receptor families.

CDw150 associates with src-homology 2-containing inositol phosphatase and modulates CD95-mediated apoptosis.

CDw150, a receptor up-regulated on activated T or B lymphocytes, has a key role in regulating B cell proliferation. Patients with X-linked lymphoproliferative disease have mutations in a gene encoding a protein, DSHP/SAP, which interacts with CDw150 and is expressed in B cells. Here we show that CDw150 on B cells associates with two tyrosine-phosphorylated proteins, 59 kDa and 145 kDa in size. The 59-kDa protein was identified as the Src-family kinase Fgr. The 145-kDa protein is the inositol polyphosphate 5'-phosphatase, SH2-containing inositol phosphatase (SHIP). Both Fgr and SHIP interact with phosphorylated tyrosines in CDw150's cytoplasmic tail. Ligation of CDw150 induces the rapid dephosphorylation of both SHIP and CDw150 as well as the association of Lyn and Fgr with SHIP. CD95/Fas-mediated apoptosis is enhanced by signaling via CDw150, and CDw150 ligation can override CD40-induced rescue of CD95-mediated cell death. The ability of CDw150 to regulate cell death does not correlate with serine phosphorylation of the Akt kinase, but does correlate with SHIP tyrosine dephosphorylation. Thus, the CDw150 receptor may function to regulate the fate of activated B cells via SHIP as well as via the DSHP/SAP protein defective in X-linked lymphoproliferative disease patients.

Monoclonal antibodies of IPO series against B cell differentiation antigens in leukemia and lymphoma immunophenotyping.

Monoclonal antibodies (mAbs) of IPO series were developed following immunization with human B cell lines RPMI-1788, Daudi, and spleen cells from a patient with hairy cell leukemia. Reactivity of these mAbs was studied on 19 human cell lines, mononuclear cells of 50 healthy persons and 142 patients with leukemias and lymphomas. It was shown that mAbs IPO-3, IPO-10 and IPO-24 define B cell-specific antigens expressed at different stages of maturation. MAb IPO-3 reacted with activated B lymphocytes. MAb IPO-10 defined the antigen which appears on B cell progenitors following HLA-DR and proceeding CD19, CD10, CD22, CD37; cy mu and CD20 and have been lost during terminal differentiation. The antigen detected by mAb IPO-24 was expressed throughout B cell ontogeny from pre-B cell until the B-blasts. MAb IPO-4 detected an antigen of activated T and B lymphocytes. These mAbs are useful tools in the leukemia and lymphoma phenotypic characterization and classification.

[Monoclonal antibodies of the IPO series in studying and diagnosing malignant lymphoproliferative diseases]. / Monoklonal'nye antitela serii IPO v izuchenii i diagnostike zlokachestvennykh limfoproliferativnykh zabolevanii.

The authors have developed a panel of monoclonal antibodies (MCA) of IPO series (Institute of Problems of Oncology, Kiev). RPMI-1788 cell line, Daudi, as well as splenocytes of a patient with hairy-cell leukemia were used for immunization of mice. It has been shown that IPO-3, IPO-10 and IPO-24 MCA are directed against differentiation antigens of human B-lymphocytes. IPO-4 MCA reveal the antigen of activated T- and B-cells. IPO-5 and IPO-20 MCA recognize HLA-ABC, while IPO-37 a common leucocytic antigen. IPO-38 MCA are directed against the nuclear antigen. The possibilities of using IPO MCA in hematology have been discussed.

[Monoclonal antibodies IPO-4 recognizing antigen-activated human T and B lymphocytes]. / Monoklonal'nye antitela IPO-4, raspoznaiushchie antigen-aktirovannye T- i B-limfotsity cheloveka.

Spleen cells from BALB/c mice previously immunized with B-lymphoblastoid cell line RPMI-1788 were fused with P3-X-63-Ag8.653 myeloma cells. Monoclonal antibodies (Ab) IPO-4 were screened on 18 cell lines by the indirect immuno-fluorescence method. Cryostat sections of tissues were stained according to the PAP technique. The Mab IPO-4 were tested for reactivity with blood cells of 17 healthy persons and 102 patients with chronic lymphocytic leukemia, acute lymphoblastic and myeloblastic leukemias, hairy cell leukemia, multiple myeloma, non-Hodgkin's lymphomas and Hodgkin's disease and mitogen stimulated lymphocytes. MAb IPO-4 were found to be directed against antigen expressed on activated T and B cells.

[Immunocytochemical methods using monoclonal antibodies and lectins in the diagnosis of lymphoblastic leukemia in children]. / Immunotsitokhimicheskie metody s ispol'zovaniem monoklonal'nykh antitel i lektinov v diagnostike limfoblastnogo leikoza u detei.

ICO, IPO, LT monoclonal antibodies and lectins were used to study blood cells in 18 children with acute lymphoblastic leukemia (ALL). The immunological phenotype has been characterized, and two cytological variants of ALL of T-cell nature, and four variants of ALL of B-cell origin have been distinguished, differing by the degree of blast cell maturity.

Monoclonal antibodies IPO-3 and IPO-10 against human B cell differentiation antigens.

Monoclonal antibodies (mAbs) IPO-3 and IPO-10 were generated following immunization of a BALB/c mice with human cell lines RPMI-1788 and Daudi respectively. The reactivity of these mAbs was studied by indirect immunofluorescence technique with 10 human cell lines, blood cells of healthy persons and patients with the malignant lymphoproliferative diseases. Studies of normal and neoplastic B cells suggest that mAbs IPO-3 and IPO-10 which recognize antigens are B lineage restricted. The presence of an antigen defined by the mAb IPO-10 appears to include most but not all the stages of B cell differentiation, whereas IPO-3 detected antigen is not represented on resting B cells and has a very limited expression on activated B lymphocytes. The results obtained with mAbs IPO-3 and IPO-10 are discussed in relation to other known B cell surface markers.

[Morphocytochemical and electron microscopic research on murine hybridoma cells producing and not producing monoclonal antibodies]. / Morfotsitokhimicheskoe i élektronno-mikroskopicheskoe issledovanie kletok myshinykh gibridom, produtsiruiushchikh i neprodutsiruiushchikh monoklonal'nye antitela.

Cytochemical and ultrastructural features of mouse hybridomas and also of the parental cells--myeloma P3-X63-Ag8.653 and spleen cells of the Balb/c mice immunized with cell line RPMI-1788 have been studied. Differences in cytomorphological signs and activity of acid phosphatase, acid nonspecific esterase, nonspecific-alpha-naphthyl acetate esterase were shown in hybrid cell lines secreting and not secreting monoclonal antibodies.

[IPO-10 monoclonal antibodies to the human B-lymphocyte differentiation antigen]. / Monoklonal'nye antitela IPO-10 k differentsirovochnomu antigenu B-limfotsitov cheloveka.

Monoclonal antibodies IPO-10 were generated following immunization of a BALB/c mice with human cell line Daudi. Reactivity of this mABs was studied by indirect immunofluorescence technique with 10 human cell lines, blood cells of healthy persons and of patients with the malignant lymphoproliferative diseases. Studies on normal and neoplastic B cell suggest that mABs IPO-10 recognizing antigen is B lineage restricted. The antigen defined by the mAb IPO-10 appear to include most but not all stages of B cell differentiation.

[Monoclonal antibodies to RPMI-1788 lymphoblastoid line cells]. / Monoklonal'nye antitela k kletkam limfoblastoidnoi linii RPMI-1788.

Monoclonal antibodies IPO-1--IPO-8 against surface antigens of B-lymphoblastoid cell line RPMI-1788 were prepared. Murine hybridomas were obtained by fusion of immune spleen cells and myeloma cells. Screening of specific antibody production was carried out by indirect immunofluorescence. Expression of these antibodies against a panel of 11 human cell lines was carried out by indirect immunofluorescence. Expression of antigens detected with IPO-1--IPO-8 were investigated on peripheral blood cells of healthy individuals and patients with CLL, ALL, myeloma and on lymph node cells of patients with Hodgkin's disease. Specificity of these MoAbs is discussed. IPO-5 is shown to react with the HLA-related determinant. The antibody IPO-3 appears to recognize a differentiation antigen of human B cells.

[Humoral reactions in BALC/c mice with sarcomatous Moloney-induced tumor]. / Gumoral'nye reaktsii myshei BALB/c pri induktsii opukholi sarkomatoznym virusom Moloni.

In a progressive course of the blastomatous process induced by MSV-Moloney the antitumor antibodies level in the whole blood serum was practically unchanged, while the level of antibody-forming cells (AFC) in the spleen of these mice was considerably decreased as compared with that in the spleen of intact mice of the same age. If the tumor development was followed by its subsequent resorption, a biphase character of enhancement of the cytotoxic activity both of the whole serum and its fractions was noted. In the utmost developed tumor a reduced AFC level was observed, while in its resorption -- a gradual restoration of the AFC values up to the level characteristic of intact animals of the same age group.