Proteins of the mineral compartment of bovine fetal enamel share common antigenic determinants with serum proteins.

Two fractions were separated from the proteins of the mineral compartment of bovine developing enamel on the basis of their affinity for the lectin concanavalin-A. A monoclonal antibody was prepared by the hybridoma technique against the Con-A-binding fraction. This antibody and a commercial polyclonal antibody against bovine serum albumin were used to examine the relationship between those proteins, serum albumin and alpha-2HS glycoprotein, two proteins concentrated within dentin and bone matrices.

Hexadecanoic and neuraminic acid incorporations in two rat colon carcinoma cell lipids: selective influence of 1-O-octadecyl 2-O-methyl-3-phosphocholine on glycerolipid and ganglioside biosynthesis.

[3H] hexadecanoic and N-acetyl [14C] neuraminic acids were incorporated in glycerolipids or gangliosides of 2 rat colon carcinoma cell lines, having (PRO cells), or not (REG cells) invasive capacities when inoculated in syngeneic BD IX rats. The cells were cultured (48 h) in presence of 1-0-octadecyl-2-0-methyl-3-phosphocholine (ET 18-0-CH3) 20 or 40 microM, which, on transformed cells, inhibits the cell growth, modifies the glycerolipid biosynthesis, and activates the sialyltransferases. ET 18-0-CH3 20 microM activated, in PRO and in REG cells the incorporation of [3H] hexadecanoate in monosialogangliosides (1.

Low expression of lymphocyte function-associated antigen (LFA)-1 and LFA-3 adhesion molecules is a common trait in Burkitt's lymphoma associated with and not associated with Epstein-Barr virus.

Lymphocyte function-associated antigens 1 and 3 (LFA-1, LFA-3) and intercellular adhesion molecule 1 (ICAM-1) are cell surface adhesion molecules necessary for immune processes requiring intercellular contact. It was recently proposed that malignant Burkitt's lymphoma cells (BL) may escape from immunosurveillance through the downregulation of LFA-1 (CD11a/CD18) or LFA-3 (CD58) and ICAM-1 (CD54) molecules. Expression of these three adhesion antigens was investigated in 19 BL lines.

7-amino-4-methylcoumarin-3-acetic acid-conjugated streptavidin permits simultaneous flow cytometry analysis of either three cell surface antigens or one cell surface antigen as a function of RNA and DNA content.

We have investigated the use of the new coumarin dye AMCA (7-amino-4-methylcoumarin-3-acetic acid), as a fluorochrome for multiple color fluorescence analysis by flow cytometry. AMCA is now commercially available as a streptavidin conjugate. Its excitation wavelength is optimal at 351/364 nm with a UV argon ion laser and it emits optimally in the blue at 450 nm.

Differential expression of carcinoembryonic antigens and non cross-reacting antigens in the human thymus. Analysis on frozen sections and cultured epithelial cells using monoclonal antibodies.

The organization of epithelial cells in distinct areas of the thymus appears important for understanding the pathways of T-cell differentiation. The presence of carcinoembryonic antigen (CEA) was investigated on sections of human thymus and in cultures of thymic epithelial cells through use of monoclonal antibodies (Mab) discriminating CEA and 2 non cross-reacting antigens (NCA 55 and NCA 95). All together, 5 monoclonal antibodies were used.

[Prenatal diagnosis and neonatal management of posterior urethral valves: apropos of 33 case reports].

The existence of valves in the posterior urethra (33 cases) carries a poor prognosis since 25 to 50% of these newborns will develop terminal renal insufficiency. Antenatal diagnosis permits early treatment and should lead to an improved functional prognosis in cases where the number of nephrons is not too low.

Sequential loss of CD34 and class II MHC antigens on purified cord blood hematopoietic progenitors cultured with IL-3: characterization of CD34-, HLA-DR+ cells.

The expression of class II MHC and CD34 antigens on human cord blood hematopoietic progenitor cells (HPC) was investigated upon culturing in the presence of interleukin-3 (IL-3). HPC isolated by "panning" according to their expression of CD34 coexpressed HLA-DR and HLA-DP, and the majority of the CD34+ HPC also expressed HLA-DQ. In the presence of IL-3, the expression of CD34 and class II MHC antigens was found to be gradually lost in culture.

Human T lymphocytes expressing the C3b/C4b complement receptor type one (CR1, CD35) belong to Fc gamma receptor-positive CD4-positive T cells.

The phenotypic characteristics of human T lymphocytes expressing the C3b/C4b complement receptor type one (CR1, CD35) were investigated using dual-color surface immunofluorescence and cytofluorometric analysis of stained peripheral blood mononuclear cells (PBMC) from normal individuals. Two to ten percent of PBMC coexpressed CR1 and the CD5, CD2, or CD3 antigen. CR1 was detected on a subset of CD4+ T lymphocytes but not on CD8+ or on Leu-7+ lymphocytes.

The role of Ca2+ and Mg2+ in the cytotoxic T lymphocyte reaction and in the secretion of N alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester-serine esterase by human T cell clones.

Human T cell clones contain enzymes that can cleave the substrate N-alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester (BLT). All CTL clones tested in this study secreted BLT-serine esterase activity, whereas only one of three tested non-cytolytic T cell clones secreted this enzymatic activity upon Ag-specific activation. BLT-serine esterase secretion could also be induced by the Fc gamma+ target cell Daudi in the presence of mAb specific for the TCR/CD3 complex, CD2, or the T cell activation Ag Tp 103.

Effects of recombinant human interleukin-3 on CD34-enriched normal hematopoietic progenitors and on myeloblastic leukemia cells.

Induction of proliferation and differentiation in response to recombinant human interleukin-3 (hIL-3) was studied in liquid and semisolid cultures of umbilical cord blood and bone marrow cells that were fractionated by "panning" with anti-My10 antibody according to expression of CD34 antigen. Cells from enriched fractions (70% to 90% CD34+) were found to proliferate strongly in response to hIL-3. Phenotypic analysis and morphologic characterization of the proliferating cells demonstrated a rapid decrease in CD34+ cells and an exponential increase in the number of cells belonging to the neutrophilic, eosinophilic, monocyte/macrophage, and thrombocytic lineages.

Interleukin 4 inhibits the proliferation but not the differentiation of activated human B cells in response to interleukin 2.

The combined effect of IL-4 and IL-2 on proliferation of anti-IgM antibody or Staphylococcus aureus strain Cowan I (SAC)-preactivated B cells was investigated. It was observed that in most cases, rIL-2 used at optimal concentration induced higher levels of tritiated thymidine ([3H]TdR) uptake than rIL-4 used at optimal concentration. When rIL-4 and rIL-2 were added together, it was repeatedly found that B cell proliferation induced by rIL-2 was significantly reduced and was, in most cases, comparable with the proliferation induced by rIL-4 alone.

Identification of cell subpopulations by dual-color surface immunofluorescence using biotinylated and unlabeled monoclonal antibodies.

A new method of dual-color immunofluorescence is presented for analysis of surface antigen distribution among heterogeneous cell suspensions. It involves flow cytometric analysis of cells stained with a biotinylated first monoclonal antibody and/or with an unlabeled second monoclonal antibody. After addition of streptavidin-phycoerythrin and/or fluoresceinated goat antimouse immunoglobulin antibody, single-cell fluorescence intensities are measured and biparametric graphic representations are obtained, allowing one to determine the percentage of cells stained by each of the monoclonal antibodies or both.

[Decrease of erythrocyte receptors for the C3b fragment of complement in acquired immunodeficiency syndrome].

The number of C3b receptors (CR1) on erythrocytes (E) was measured, using a newly developed flow cytometry assay and a standard radioimmunoassay, in HIV-infected individuals and in a normal control population. The number of CR1/E was significantly decreased in symptomatic HIV-infected patients with ARC and acquired immunodeficiency syndrome and was normal in asymptomatic carriers of anti-HIV antibodies. Decreased numbers of CR1/E correlated with the clinical severity of the HIV-related disease.

Regulation of Fc receptor for IgE (CD23) and class II MHC antigen expression on Burkitt's lymphoma cell lines by human IL-4 and IFN-gamma.

The effect of rIL-4 on the expression of low affinity receptor for the Fc part of IgE (Fc epsilon R2/CD23) and class II MHC antigens on Burkitt's lymphoma (BL) cell lines was investigated. Some of the BL lines contained low percentages of CD23 and HLA-DQ-positive cells, but virtually all cells expressed HLA-DR. IL-4 induced CD23 and class II MHC Ag expression on 7 of 9 BL.

CD4 is involved in a post-binding event in the cytolytic reaction mediated by human CD4+ cytotoxic T lymphocyte clones.

CTL lyse their target cells in discrete phases. First, the CTL bind to the target cell in a Mg2+-dependent manner followed by a Ca2+-dependent cytolytic phase. In the present study, we investigated the role of CD4 in the different phases of the cytolytic reaction mediated by human CD4+ class II MHC-specific CTL clones by using a single cell assay.

Epstein-Barr virus (EBV) induces expression of B-cell activation markers on in vitro infection of EBV-negative B-lymphoma cells.

A set of B-cell activation markers, including the EBV/C3d receptor [complement receptor type 2 (CR2) (CD21)], the 45-kDa lymphoblastoid cell-associated (Blast-2) antigen (CD23), and the B-cell restricted activation (Bac-1) antigen (which was recently identified as a potential B-cell growth factor receptor) can be turned on by infecting lymphoma cells that are genome negative for Epstein-Barr virus (EBV) with the B95-8 immortalizing strain of the virus. The nonimmortalizing EBV variant, strain P3HR-1, which possesses a deletion within the BamHI WYH region of the genome containing the coding sequence for the EBV-determined nuclear antigen 2, does not induce expression of these markers. Other lymphoblastoid cell-associated antigen markers can be activated by infection with either immortalizing or nonimmortalizing viruses.

Regulation by anti-CD2 monoclonal antibody of the activation of a human T cell clone induced by anti-CD3 or anti-T cell receptor antibodies.

In this study the effect of anti-cluster designation (CD) 2 monoclonal antibodies (mAb) on the activation of a cloned human T cell line, HY837, after triggering the CD3/T cell receptor (TcR) complex by anti-CD3 or anti-TcR mAb is described. HY837, which reacts with a series of mAb directed at different epitopes on the TcR, could be induced to proliferation and interleukin 2 (IL-2) production by soluble mAb directed at the CD3/TcR complex in the absence of accessory cells. mAb directed at the CD2 epitope T11-1 were shown to block the IL-2 production by HY837, as well as the expression of the IL-2 receptor, induced by anti-CD3 mAb, resulting in the inhibition of the proliferative response.

B cell growth-promoting activity of recombinant human interleukin 4.

Human interleukin 4 (IL-4), also known as B cell stimulatory factor 1, is a T cell-derived glycoprotein consisting of 129 amino acids for which a cDNA has been recently isolated. IL-4 displays little or no B cell growth factor (BCGF) activity in the standard anti-IgM costimulatory assay using suboptimal concentrations of soluble anti-IgM antibody whereas the low m.w.

Human recombinant interleukin 4 induces Fc epsilon receptors (CD23) on normal human B lymphocytes.

Human rIL-4 is able to induce the expression of low-affinity receptors for IgE (Fc epsilon RL/CD23) on resting B lymphocytes, as determined by the binding of either the anti Fc epsilon RL/CD23-specific mAb 25 or IgE. Stimulation of B cells with insolubilized anti-IgM antibody increases the number of cells expressing Fc epsilon RL/CD23 upon culturing with IL-4 and enhances the level of Fc epsilon RL/CD23 expression on these cells. Fc epsilon RL/CD23 induction is specific for IL-4 since IL-1 alpha, IL-2, IFN-gamma, B cell-derived B cell growth factor (BCGF), and a low-molecular-weight BCGF were ineffective.

Enumeration of CR1 complement receptors on erythrocytes using a new method for detecting low density cell surface antigens by flow cytometry.

A sensitive enhancing system was developed for detecting low density cell surface antigen by flow cytometry. The system termed the 'super avidin-biotin system' (SABS) uses biotinylated antibody, phycoerythrin-streptavidin (StreptA-PE), biotinylated goat anti-streptavidin antibody, and StreptA-PE. CR1 complement receptor antigenic sites were quantified on erythrocytes from healthy individuals and patients with antibodies against human immunodeficiency virus (HIV) using SABS and a conventional radioimmunoassay (RIA) with monoclonal anti-CR1 antibody.

Production and characterization of a monoclonal antibody specific for the human lymphocyte low affinity receptor for IgE: CD 23 is a low affinity receptor for IgE.

In the present study a gamma 1 kappa monoclonal antibody, Mab 25, specific for the receptor for the Fc fragment of IgE on lymphocytes (Fc epsilon RL) was established. This antibody was generated after fusion of spleen cells from mice immunized with the EBV-transformed lymphoblastoid cell line RPMI 8866, which is known to express Fc epsilon RL at high density. Mab 25 inhibits strongly the binding of IgE to RPMI 8866 cells and to other Fc epsilon RL-positive EBV-transformed lymphoblastoid cell lines.

DNA damage by chemically generated singlet oxygen.

A naphthalenic endoperoxide was used as a non-photochemical source of singlet oxygen (1O2) to examine some interactions between this reactive oxygen species and DNA. High molecular weight DNA (ca. 10(8) daltons) was exposed to 120 mol m-3 1O2 (cumulative concentration) and analyzed for interstrand crosslinkage by hydroxyl apatite chromatography following formamide denaturation.

Human interferon-gamma acts as a B cell growth factor in the anti-IgM antibody co-stimulatory assay but has no direct B cell differentiation activity.

In this study it is illustrated that recombinant human interferon-gamma (IFN-gamma) acts as a B cell growth factor (BCGF) in the anti-IgM antibody co-stimulatory assay. A monoclonal antibody that specifically inhibits the biological activities of IFN-gamma blocks its BCGF activity supporting the specificity of the IFN-gamma effect. Various IFN-gamma obtained from different sources displayed the same BCGF activity.