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Biomedical subjects

T A Springer

Publications and source records attributed to T A Springer.

At least 307 records · Page 17Linked to original sources
PubMed1983

Staining of Langerhans cells with monoclonal antibodies to macrophages and lymphoid cells.

Langerhans cells are Ia-bearing antigen-presenting cells in the epidermis that share many functions with macrophages. We have used monoclonal antibodies to the macrophage antigens, Mac-2 and-3, Ia antigen, Fc fragment receptor and the common leukocyte antigen CLA to compare the cell surface antigens of these cells with those of interdigitating and follicular dendritic cells and of macrophages in lymphoid tissues. Immunoperoxidase staining was carried out with epidermal sheets from BALB/c mice and epidermal cell suspensions enriched for Langerhans cells by Fc rosetting. Langerhans cells stained for all of these antigens. Comparison with the staining properties of other dendritic cells and macrophages, in combination with previous observations, indicates a close relationship of Langerhans cells to the interdigitating cells of lymphoid tissues.

Animals↗
PubMed1983

All monocyte antigens are not expressed on renal endothelium.

Recently a tissue restricted antigen system, which is expressed on endothelial cells and monocytes (E-M antigens) but not lymphocytes, has been associated with kidney graft rejection. In screening sera from recipients of kidney, bone marrow or skin grafts for possible reactivity with endothelial cell antigens, we have found that all (13 of 13) endothelial reactive sera also reacted with monocytes, but that many (21 of 34) monocyte reactive sera did not react with endothelial cells. Additionally, one well-defined monoclonal antibody (M1/70), which was cytotoxic for human monocytes, neither stained renal endothelium nor was absorbed by renal endothelium when perfused through a human kidney. Thus, not all monocyte antigens appear to be expressed in high concentrations on renal vascular endothelium. This may explain why monocyte reactive antibodies do not always correlate with kidney graft rejection.

Absorption↗
PubMed1983

Monoclonal antibodies against rat glomerular antigens: production and specificity.

To define the characteristics and target antigens (Ags) of nephrotoxic antibodies (Abs) and to analyze the factors that govern the evolution of Ab-mediated glomerular injury, we have prepared monoclonal Abs against rat glomerular Ags. BALB/c mice were immunized with Lewis rat cortex or glomeruli, and their spleens were removed and fused with hypoxanthine-aminopterin-thymidine supplement-sensitive myelomas. Hybrids were selected for production of Abs against Lewis rat kidney by indirect immunofluorescence. To date, more than 50 positive hybrids have been selected and their tissue reactivity defined by indirect immunofluorescence and immunoelectron microscopy. Of these, 14 are presented here in detail. One of these monoclonal Abs, K9/4, recognizes a unique Ag present exclusively on the cell surface of rat glomerular visceral epithelial cells. Four Abs (K12/2, K17/4, K12/5, and K12/8) recognize sites within the glomerular basement membrane; K12/2 and K17/4 also bind to vascular basement membranes of the rat, whereas K12/5 and K12/8 bind to glomerular basement membrane, tubular basement membranes, and vascular and epithelial basement membranes in all tissues of the rat. Two hybridomas (K6/1 and K6/3) recognize determinant(s) present on cell surfaces of endothelial and epithelial cells as well as within the glomerular basement membrane. All of these previously mentioned Abs are species restricted (i.e., they bind only to rat tissue) and, with the exception of K9/4, bind upon in vivo administration. Several others, however, recognize ubiquitous Ags that are present on intracellular structures in every species tested. The tissue distribution of these Ags suggests that they are present in contractile or cytoskeletal elements and, as expected from their intracellular location, monoclonal Abs directed against these components do not bind upon in vivo administration. Future studies will be directed at defining the antigenic composition of the glomerular capillary wall and the relevance of such Ags in immune-mediated glomerular injury.

Animals↗
PubMed1983

Human lymphocyte function associated antigen-1 (LFA-1): identification of multiple antigenic epitopes and their relationship to CTL-mediated cytotoxicity.

Human lymphocyte function-associated antigen (LFA)-1, a heterodimeric lymphocyte surface glycoprotein of 177,000 and 95,000 relative molecular weight has been implicated to function in the cytotoxic T lymphocyte (CTL) effector mechanism. Seven mouse hybridoma lines producing monoclonal antibodies (MAb) reactive with this structure were studied. Three unique and 3 partially over-lapping epitopes on human LFA-1 were defined by competitive cross inhibition binding assays using biosynthetically labeled anti-LFA-1 MAb. In contrast, of five rat antimouse LFA-1 MAb, all five recognized a common or shared epitope. An HLA-B7 specific human CTL line expressed 1.1 X 10(5) LFA-1 sites per cell with a direct saturation binding assay. Human CTL expressed two to four times more LFA-1 than peripheral blood lymphocytes or B and T lymphoblastoid cell lines. Titration of each of the anti-LFA-1 MAb in a 51chromium release cytolytic assay revealed quantitative differences in the ability of the different anti-LFA-1 MAb to block cytolysis indicating distinct functional and antigenic epitopes exist on the human LFA-1 molecule. Anti-LFA-1 MAb reversibly inhibited the CTL reaction by slowing the initial rate of cytolysis. These results suggest anti-LFA-1 MAb inhibit CTL function by specific blockade of a functionally relevant molecule.

Animals↗
PubMed1983

Cytotoxic T cells directed against HLA-DR antigens and their surface proteins.

The authors review their recent research involving the generation of cytotoxic T lymphocytes (CTL) directed against HLA-DR antigens. A mouse anti-human xenogeneic system first suggested that HLA-DR antigens could be recognized by CTL. Human allogeneic CTL specific for HLA-DR6 were generated and found to be OKT4+. The fact that these CTL were OKT4+ while anti HLA-A,B CTL were OKT8+ suggested that these T cell surface antigens may be involved in MHC antigen recognition; ie, they may be part of the T cell receptor. These OKT4+, HLA-DR specific CTL were further used to generate monoclonal antibodies (1) which block cytolysis and define novel antigens involved in the CTL-target interaction and (2) which define an antigenic complex on alloantigen activated T cells.

Animals↗
PubMed1983

Dendritic cell and macrophage staining by monoclonal antibodies in tissue sections and epidermal sheets.

Mouse tissue sections were stained by monoclonal antibodies to macrophage antigens (Mac-1 (M1/70), Mac-2 (M3/38), Mac-3 (M3/84) with the use of immunoperoxidase. Mac-1 was located diffusely in the cytoplasm of round cells in a high percentage of alveolar macrophages, resident peritoneal and bone marrow cells, in splenic red pulp, and in rare perivascular cells in the thymus. Mac-1 was absent in epithelial cells and Langerhans cells. Mac-2 was strongly positive in many dendritic cells in the thymic medulla, more than the cortex, in paracortex and medulla of lymph nodes, sparing the follicles, and in the marginal zone of spleen. There were a few positive cells in germinal centers. Mac-2 was located in a low percentage of bone marrow and a high percentage of resident peritoneal cells. When positive in sections Mac-3 always showed granular cytoplasmic staining. Bone marrow showed a high percentage of cytoplasmic staining (greater than 50%), as compared with low surface staining (less than 1%). It was found in hematopoietic cells, and in all endothelium, including postcapillary venules and lining of sinuses. It was probable that the resulting dendritic staining pattern for Mac-3 in paracortex of lymph node, white and red pulp, thymic cortex, and medulla included dendritic cells other than endothelial cells. Alveolar macrophages and Kupffer cells were positive for Mac-2 and Mac-3. Mac-3 also stained bile canaliculi. Clearly different staining patterns were found in epithelial cells for Mac-2 and Mac-3 in kidney tubules, intestinal mucosal lining, bronchi, choroid plexus, and epidermis.

Animals↗
PubMed1983

The functional significance, distribution, and structure of LFA-1, LFA-2, and LFA-3: cell surface antigens associated with CTL-target interactions.

Three cell surface antigens associated with the cytolytic T lymphocyte(CTL)-target cell interaction were identified by generation of monoclonal antibodies (MAb) against OKT4+, HLA-DR-specific CTL and selection for inhibition of cytolysis in a 51Cr-release assay. These MAb block cytolysis by both OKT4+ and OKT8+ CTL and the proliferative responses to PHA and the mixed lymphocyte response (MLR). LFA-1 is an antigen widely distributed on lymphoid tissues and is composed of two polypeptides of 177,000 and 95,000 Mr on all cell types studied. Anti-LFA-1 MAb block NK cell-mediated cytolysis in addition to T lymphocyte-mediated cytotoxicity and proliferation. LFA-2 (Mr = 55,000 to 47,000), a determinant on the sheep red blood cell receptor, is expressed by T cells but not B cells and appears specific for T cell functions. LFA-3 (Mr = 60,000) is a widely distributed antigen present on both hematopoietic and nonhematopoietic tissues and appears to only be involved in T cell functions. MAb to LFA-1 and LFA-2 inhibit function by binding to effector cell surface molecules, whereas anti-LFA-3 MAb appear to block by binding to the target cells. Together with previously described molecules, LFA-1, LFA-2, and LFA-3 demonstrate the complexity of CTL-mediated cytotoxicity at the molecular level.

Antibodies, Monoclonal↗
PubMed1983

Blocking of CTL-mediated killing by monoclonal antibodies to LFA-1 and LYT-2,3. I. Increased susceptibility to blocking after papain treatment of target cells.

It is now established that monoclonal antibodies (MAb) against LFA-1 and Lyt-2,3 antigens on cytolytic T lymphocytes (CTL) block killing function in the absence of C. It has been suggested that the blocking is inversely related to CTL-target affinity. In this report, we studied the effect of papain pretreatment of target cells, because papain is known to remove H-2 and to render target cells more resistant to allospecific CTL. CTL-target conjugate formation was weaker with papain-treated target cells (based on reduced post-dispersion lysis in dextran-containing medium). The concentration of MAb required to produce 40 to 60% inhibition of 51Cr release (2-hr assay) was reduced four to 29-fold for alpha LFA-1 and 64 to 114-fold for alpha Lyt-2,3. Papain, however, did not induce blocking by MAb to other CTL antigens such as Thy-1, H-2, and T200. Flow cytometric analysis confirmed that papain selectively removed more than 95% of H-2. In kinetic studies of removal and recovery, H-2 density and conjugate formation correlated well with each other. Sensitivity to blocking was not as well correlated, raising the possibility that an unidentified papain-sensitive target cell molecule other than H-2 plays an important role in CTL-target interaction.

Animals↗
PubMed1983

Lymphokine inducing "terminal differentiation" of the human monoblast leukemia line U937: a role for gamma interferon.

The human monoblast leukemia line, U937, is growth-inhibited and induced to develop markers of mature monocytes by lymphokine preparations. Lymphokine is cytostatic and induces expression of Fc receptors in U937 and in myelomonocytic leukemic lines RC-2A and KG-1, but does not have these effects on T- and B-lymphocytic lines. In addition to previously described properties, including complement receptors, phagocytosis, and antibody-dependent cellular cytotoxicity (ADCC), Mac-1 and Mac-3 surface antigens defined by monoclonal antibodies are induced on U937 cells by lymphokine and phorbol ester. The Mac-1 surface component appears to have a regulatory role in differentiation of the monocyte lineage line, since antibodies to this antigen block the induction of Mac-3 antigen. The lymphokine activity was concentrated by salt precipitation and characterized by ion-exchange and size chromatography. Fractions of about 40,000 daltons were responsible for growth inhibition and induction of Fc receptors and Mac-1 antigen in U937 cells. However, ADCC was not induced in U937 by individual fractions of lymphokine, suggesting that this cytotoxic capacity may be regulated by a lymphokine of a different size, which is only effective after initial maturation steps. Since gamma-interferon is present on the 40K size range of lymphokine, the possibility that interferon is a differentiation modulator for the monoblast cells was investigated. Highly purified gamma-interferon (10(7) U/mg protein) at 10-300 U/ml inhibited growth and induced Fc receptors in U937 similar to the effect of lymphokine. The Fc-receptor-inducing activity of lymphokine was inhibited by a neutralizing monoclonal antibody to gamma-interferon, suggesting that this differentiation factor in lymphokine is gamma-interferon.

Animals↗
PubMed1983

Stable hamster-mouse hybridomas producing IgG and IgM hamster monoclonal antibodies of defined specificity.

Specific antibody-secreting hybridomas have been obtained by fusing Syrian or Armenian hamster (Mesocricetus auratus or Cricetulus migratorius) spleen cells with mouse myeloma cells. The hamsters were immunized to mouse cytolytic T lymphocytes. Hybrids were selected either by an indirect binding assay using an 125I-monoclonal antibody (MAb) reactive with hamster kappa-chains or by their ability to block T cell-mediated cytolysis. Three hybridoma clones were obtained that secreted intact IgM-like and IgG-like hamster MAb as shown by SDS-PAGE. The clones were stable as shown by subcloning. Two MAb recognized antigens of wide tissue distribution; the third bound specifically to T lymphocytes, gave strong inhibition of T cell-mediated cytolysis, and immunoprecipitated the Lyt-2,3 molecule.

Animals↗
PubMed1982

Purification and structural characterization of LFA-1, a lymphocyte function-associated antigen, and Mac-1, a related macrophage differentiation antigen associated with the type three complement receptor.

LFA-1, an antigen associated with antigen-specific T lymphocyte-mediated killing, and Mac-1, a macrophage differentiation antigen associated with type three complement receptor function, contain alpha chains of Mr = 180,000 and 170,000, respectively, and beta chains of Mr = 95,000. The monoclonal antibodies defining these antigens do not cross-react. The LFA-1 and Mac-1 beta chains are highly homologous or identical, whereas the alpha chains are highly different by tyrosyl tryptic peptide mapping (Kürzinger, K., Ho, M. K., and Springer, T. A. (1982) Nature (Lond.) 296, 668-670). T lymphoma cell lines express LFA-1 but not Mac-1 as shown by immunofluorescence and immunoprecipitation. Conversely, some macrophage-like lines express Mac-1 but not LFA-1. Other macrophage-like lines co-express Mac-1 and small amounts of LFA-1. Mac-1 and LFA-1 are present as separate molecules in these cells. [35S]Methionine and [[3H]glucosamine are incorporated into both alpha and beta chains of Mac-1 and LFA-1, showing both chains are endogenously synthesized and are glycoproteins. Cross-linking and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis experiments show that in both Mac-1 and LFA-1 the alpha and beta chains are noncovalently associated in alpha 1 beta 1 quaternary structures. By quantitative immunofluorescence flow cytometry, the EL-4 T lymphoma and P388D1 macrophage-like lines were estimated to express 10(5) LFA-1 and 1.6 x 10(5) Mac-1 molecules/cell, respectively. From these sources the antigens have been purified to homogeneity in 200-400-micrograms quantities by monoclonal antibody affinity chromatography. The purified antigens contain only the alpha and beta subunits.

Animals↗
PubMed1982

Anti-Mac-1 selectively inhibits the mouse and human type three complement receptor.

Anti-Mac-1 (M1/70), a rat monoclonal antibody that reacts with mouse and human macrophages, polymorphonuclear leukocytes (PMNL), and natural killer cells, selectively inhibited complement receptor-mediated rosetting by murine macrophages and human PMNL. Preincubation of macrophages with anti-Mac-1 inhibited formation of rosettes with sheep erythrocytes bearing IgM antibody and murine C3 fragments. No inhibition was observed when other monoclonal antibodies that react with macrophages (such as anti-Ly5, anti-H-2, or anti-pan-leukocyte) were tested at 10-fold higher concentrations. Anti-Mac-1 did not affect macrophage Fc receptor-mediated rosetting. Erythrocytes bearing homogeneous human C3 fragments C3b (EC3b) or C3bi (EC3bi) were used to test the specificity of the murine macrophage and human PMNL complement receptor inhibited by anti-Mac-1. In both cases, anti-Mac-1 inhibited CR3-mediated rosetting of EC3bi but not CR1-dependent rosetting of EC3b. The results show that Mac-1 is either identical to CR3 or closely associated with CR3 function. This is one of the first cases in which a monoclonal antibody-defined differentiation antigen has been associated with a specific cell surface function.

Animals↗
PubMed1982

The molecular basis for cytolytic T lymphocyte function: analysis with blocking monoclonal antibodies.

During the past decade the mechanism of CTL-mediated killing has been resolved into 3 steps, and its cation requirements, and general nature have been well defined. However, biochemical understanding of the CTL-target interaction has made little progress. Recently, we have developed a monoclonal antibody (MAb) which blocks killing by binding to a previously undescribed molecule on the CTL membrane, a molecule which we therefore have termed lymphocyte function-associated antigen one (LFA-1). LFA-1 and Lyt-2,3 are the only presently identified sites for such blocking; antibodies to over a dozen other molecules expressed on the CTL do not block killing. Present evidence suggests that LFA-1 is crucial in the adhesive interaction of T cells with other cells (e.g., targets, macrophages, perhaps B cells) The continuing search for blocking MAbs provides a systematic way to link specific molecules with CTL function.

Animals↗
PubMed1982

Three distinct antigens associated with human T-lymphocyte-mediated cytolysis: LFA-1, LFA-2, and LFA-3.

Monoclonal antibodies were prepared to anti-HLA-DR cytolytic T lymphocytes (CTLs) and screened for inhibition of CTL-mediated killing. Binding of monoclonal antibodies to four types of molecules, LFA-1, LFA-2, LFA-3, and HLA-DR, inhibited killing, suggesting that these molecules participate in the CTL-target cell interaction. The antigens were characterized by immunoprecipitation, crosslinking, NaDodSO4/polyacrylamide gel electrophoresis, and immunofluorescence flow cytometry. The LFA-1 antigen contains alpha and beta polypeptide chains of Mr 177,000 and 95,000 that are noncovalently associated in an alpha 1 beta 1 structure. It is present on both B and T lymphocytes and marks subpopulations that differ in quantitative expression. Human LFA-1 appears to be the homologue of mouse LFA-1. Human LFA-2 is of Mr 49,000 with a minor component of Mr 36,000. It is expressed on CTL lines but not on a B-cell line and in peripheral blood preferentially on T lymphocytes. Human LFA-3 is of Mr 60,000 and is expressed on both B and T lymphocytes.

Animals↗