Showing papers on "Antibody published in 1978"

A better cell line for making hybridomas secreting specific antibodies

Abstract: FUSION of myeloma cells which grow in tissue culture with spleen cells from an immunised mouse provides a general method for obtaining cell lines (hybridomas) which make antibody of the desired specificity1–3. Hybrids derived from these myelomas make the immunoglobulin (Ig) heavy and light chains of the myeloma parent as well as the antigen-specific heavy and light chains of the spleen cell parent. In conditions in which the two heavy and two light chains associate randomly, a hybridoma would make 10 distinct Ig molecules, and the specific antibody would comprise only 1/16 of the total Ig4,5. To obtain hybridomas making only the specific antibodies requires a tumour cell fusion partner that itself makes no Ig but which can nevertheless be fused with spleen cells to obtain hybrids secreting only the specific antibody. We report here the identification of such a cell line, Sp2/0-Ag14.

Monoclonal antibody defining a stage-specific mouse embryonic antigen (SSEA-1).

Abstract: A monoclonal antibody derived by fusion of mouse myeloma cells with spleen cells from a mouse immunized with F9 teratocarcinoma cells is described. This antibody, which reacts with embryonal carcinoma cells of mouse and human origin and with some preimplantation stage mouse embryos, defines an embryonic stage-specific antigen. This stage-specific antigen (SSEA-1) is first detected on blastomeres of 8-cell stage embryos. Trophectodermal cells are transitorily positive; however, each cell in the inner cell mass eventually expresses this antigen.

Microdroplet testing for HLA-A, -B, -C, and -D antigens. The Phillip Levine Award Lecture.

Abstract: The microdroplet lymphocyte cytotoxicity test is universally accepted as the standard test for HLA antigen determination. An update of the technical details of the test is given, based on the authors’ testing 160,000 persons. Methods for quality control of the test as well as reproducibility data are provided. International standardization of the specificities has been accomplished by seven international workshops and a continuous cell exchange involving testing of 108 cells since 1974 by as many as 180 laboratories. The test has recently become applicable to the detection of HLA-D determinants, previously thought to be detectable only by lymphocyte-determined (LD) tests. Purified peripheral blood lymphocytes are reacted with antisera from which HLA-A, -B, and -C antibodies have been removed. B lymphocytes were found to be smaller than T lymphocytes by Coulter counter sizing. The purity of cell suspensions enriched for B lymphocytes can be individually monitored, as shown by the reactions produced by 126 test samples. HLA-D antigens have a linkage disequilibrium with certain HLA-A and -B specificities as demonstrated by population and family studies. Haplotypes found in 34 parents of 18 families demonstrate the new haplotypes, which now consist of four antigens per haplotype. Studies of HLA-D frequencies in Caucasians, Negroes, and Orientals show a distinctive distribution in the races. B lymphocytes also appear to have an autoantigen against which autoantibodies are readily produced. The autoantibodies are more active against B than T lymphocytes and act most effectively at 5 C. Although they appear in many diseases, most notably in systemic lupus erythematosus, they also occur in 10% of normal males and females. In patients awaiting kidney transplants, antibodies against B lymphocytes are often found. Patients with cold B-cell antibodies (autoantibodies) were shown to have higher transplant survival rates than those with warm B-cell antibodies (allogeneic). Thus, in performing crossmatch tests it is now necessary to distinguish antibodies against T and B lymphocytes and those that react in cold and in warm conditions.

Autoantibody to a Nuclear Antigen in Proliferating Cells

Abstract: This study reports the identification of an autoantibody in the sera of some patients with systemic lupus erythematosus that reacted with nuclear antigen(s) of proliferating cells. The autoantibody was initially detected by the observation that it did not react in immunofluorescence with nuclei of renal tubular or glomerular cells, nor with hepatic parenchymal cells, but only reacted with scattered cells in the interstitial tissue of these two organs. In contrast, many lymphocytes in lymph node follicles, spleen, and thymus reacted with this antinuclear antibody. Normal peripheral blood lymphocytes did not show nuclear staining but after mitogenic stimulation, 20% of cells became positive. Nuclear staining was not restricted to lymphocytes but was also observed in several tissue culture cells lines such as Hep-2 cells (human epithelial carcinoma), Ehrlich ascites tumor cells, and baby hamster kidney cells. The reactive nuclear antigen(s) was soluble in physiologic saline and reacted with serum autoantibody to give a precipitin line in immunodiffusion that was immunologically distinct from DNA and other known nuclear antigen-antibody precipitating systems. Autoantibodies to proliferating cell nuclear antigen(s) might serve as useful biologic markers to study stimulated lymphocytes and other proliferating cells.

Monoclonal xenogeneic antibodies to murine cell surface antigens: identification of novel leukocyte differentiation antigens

Abstract: Hybrid myeloma cell lines secreting monoclonal antibodies to mouse cell surface antigens have been prepared. Spleen cells from a DA rat immunized with B10 mouse spleen cells that had been enriched for T cells were fused to cells from a nonsecreting mouse myeloma line (NSI). The presence in the culture supernatants of antibodies binding to mouse spleen cells was tested by a binding assay with 125I-labeled anti-rat IgG. From a large number of positive cultures, ten independent hybrid clones were purified, each secreting a different antibody. Each antigenic target was analyzed by (a) gel electrophoresis of immunoprecipitated 125I-labeled cell surface molecules, (b) heat stability, (c) strain and species distribution and (d) cross-inhibition of binding of different monoclonal antibodies. It was concluded that the ten monoclonal antibodies regognized four types of antigen. One was the heterophile, heat-stable, Forssman antigen. The second (mol.wt. 210 000) appears to be a major 125I-labeled lymphoid cell surface protein. The third, a minor component of spleen cells, was precipitated as two polypeptides of mol.wt. 190 000 and 105000. Five IgG-secreting clones identify the fourth antigen, a heat-stable, possibly glycolipid component expressed on mouse red blood cells and also on thymocytes. Cross-inhibition studies suggest that these last monoclonal antibodies bind to overlapping, but not identical, determinants. The class and chain composition of the monoclonal antibodies were studied by gel electrophoresis, isoelectric focusing and ability to lyse red blood cells and thymocytes.

Method of producing antibodies

Abstract: Continuous cell lines of genetically stable fused cell hybrids capable of producing large amounts of monoclonal antibodies against specific viruses and their antigenic determinants have been developed. The cell lines are fused cell hybrids between viral antibody producing cells and myeloma cells. Fused cell hybrids between influenza virus-primed mouse spleen cells and mouse myeloma cells can be maintained indefinitely in culture and continue to produce large amounts of anti-influenza antibody.

Subclass restriction of murine anti-carbohydrate antibodies.

Abstract: Examination of the subclass distribution of murine antibodies directed against groups A and C streptococcal carbohydrate, alpha-(1 leads to 3) dextran and phosphocholine yields the surprising observation that these carbohydrate antigens stimulate IgG responses largely restricted to the rare IgG3 subclass This subclass restriction is particularly impressive in light of the low circulating levels of IgG3 in nonimmune mouse serum and the failure of a variety of other antigens including proteins and aromatic haptens to stimulate IgG3 antibody production Attempts to alter the subclass restriction of antibodies with carbohydrate specificity by immunization with carbohydrate-coupled protein have been unsuccessful and indicate that immunoregulation of subclass expression probably occurs at the level of the antibody forming (B) cell It is therefore conceivable that VH regions of murine immunoglobulins may be restricted to particular IgG subclasses A similar type of subclass restriction has been reported in human and rat anti-carbohydrate antibodies This recruitment of a minor immunoglobulin isotype by carbohydrate antigens in several species further supports the concept of immunoregulation at the level of subclass, and suggests that these and other mammals may share a structurally similar isotype with perhaps a common evolutionary origin

Type B Hepatitis after Transfusion with Blood Containing Antibody to Hepatitis B Core Antigen

Abstract: We tested the hypothesis that donor blood containing antibody to hepatitis B core antigen (anti-HBc) but lacking detectable hepatitis B surface antigen (HBsAg) and antibody (anti-HBs)might transmit Type B hepatitis by examining donor and recipient serums from a Veterans Administration study of post-transfusion hepatitis. Donor blood was available from three patients with Type B hepatitis and from one patient with hepatitis B virus infection (development of anti-HBs and anti-HBc) without symptomatic disease. All four had received 1 unit of blood with high titer of anti-HBc but lacking HBsAg and anti-HBs. In contrast, no such units had been transfused into nine patients with "immunization-like" response (development of anti-HBs without anti-HBc) or into 26 control patients. These data stress the importance of anti-HBc as an indicator of hepatitis B virus infection and support the hypothesis that high-titer anti-HBc-positive blood might be infectious.

Islet-cell-surface antibodies in juvenile diabetes mellitus.

Abstract: Using an indirect immunofluorescence test on suspensions of viable, insulin-producing islet cells from rats, we found that 32 per cent (28/88) of insulin-treated patients with juvenile diabetes have isletcell-surface antibodies in their circulation. These antibodies also occurred in four of nine children with glucose intolerance, in one of 24 healthy children and in nondiabetic children with thyroid disorders. In the diabetic children, the immunofluorescent reaction was inhibited by preadsorption of serum to islet cells but was little affected by preadsorption to rat hepatocytes or erythrocytes or to acetone powders of various rat tissues, including pancreas. These results show that organ-specific, non-species-specific antibodies reactive with the cell surface of the islet cells can be present in serum from diabetic children, and provide an approach to investigation of immunopathological aspects of diabetes mellitus. (N Engl J Med 299:375–380, 1978)

Determinant selection and macrophage function in genetic control of the immune response

Abstract: The immune response to insulin, in both mouse and guinea pig, is under control of H-linked immune response genes. When immunized with either pork or beef insulin in CFA, both strain 2 and 13 guinea pigs respond by antigen-specific lymphocyte proliferation and synthesis of specific antibody. The specificities of the elicited antibodies and indistinguishable between these inbred strains. By constrast, strain 2 T cells recognized a distinct region of the A chain alpha loop consisting of amino acid residues 8, 9 and 10, while strain 13 T cells see an as yet undefined region of the B chain. H2b (A chain alpha loop responder) and H2d (B chain responder) mice similarly discriminate which areas of the molecule are recognized by their T lymphocytes. The function of the Ir gene in both the guinea pig and mouse appears to be an intramolecular selection of discrete regions within the antigen for recognition by the T cell. The data presented suggest that this function operates at the level of the macrophage.

Study of antibodies against human melanoma produced by somatic cell hybrids.

Abstract: We fused spleen lymphocytes obtained from mice immunized against a human melanoma cell line and melanoma-mouse hybrid cells with the P3 X 63 Ag8 mouse myeloma in order to produce hybrids secreting antibodies against a human melanoma. Antibodies secreted by individual hybrids were tested for their reaction with a panel of human melanoma, colorectal carcinoma, and normal cells in an indirect radioimmunoassay, and they displayed different specificities and crossreactivities. Some reacted only with melanomas, whereas others crossreacted with normal human or human colorectal carcinoma cells. By analysis of competitive binding of mixtures of monoclonal antibodies, it was possible to delineate different epitopes on melanomas. Hybrids growing in nude mice and producing antimelanoma antibody suppressed growth of melanoma tumors.

Murine B Cell Leukemia Line with Inducible Surface Immunoglobulin Expression

Abstract: A chemically induced leukemia of BDF 1 mice, designated 70Z/3, was adapted to tissue culture in our laboratory A minority of these cells displayed surface immunoglobulin (sIg) as detected by immunofluorescence with rhodamine-labeled class (IgM)-specific antibodies Addition of the B cell mitogen, LPS, to the cultures induced sIg expression on all of these cells The kinetics of this transition were dependent on the dose of LPS As little as 01 µg/ml induced sIg on >97% of the cells within 36 hr DxS also induced sIg whereas other mitogens (Con A, PPD) or inducing agents (DMSO, dimethyl formamide, butyric acid), tested over a wide range of concentrations, failed to induce sIg expression The cells bear H-2 antigens but lack IgD, IgG, IgA, Ia, and Thy 12 Exposure to LPS had no effect on the presence or absence of these structures A small percentage of cells possessed receptors for complement and for the Fc portion of immunoglobulin Cytoplasmic IgM was detectable within all of the cells, and constitutive production of small quantities of IgM was confirmed by SDS-polyacrylamide gel electrophoresis of serologic precipitates of cell lysates after pulsing with radioactive amino acids Using similar methods, we failed to detect active secretion of immunoglobulin Thus, this cell line has properties similar to cytoplasmic Ig + , surface Ig - cells found in immature tissues and in bone marrow of mice and humans that are thought to be immediate precursors of sIg + B lymphocytes It may provide a model for studying the mechanism of LPS activation and the molecular events associated with externalization of cell surface receptors

Use of anti-idiotypic antibodies as cell-surface receptor probes

Abstract: Anti-idiotypic antibodies have been raised against antibodies to retinol-binding protein (RBP) and to insulin. After absorption the anti-idiotypic antibodies recognized the antigen-combining sites of the antibodies used as the immunogen but of no other antibodies. Some of the anti-idiotypic antibodies raised against antibodies to RBP bound specifically to rat intestine epithelial cells, which have a physiological cell-surface receptor for RBP. The RBP receptor mediates the uptake of retinol from RBP to the cells. This uptake was abolished in a concentration-dependent manner by the anti-idiotypic antibodies, which obviously competed with RBP for binding to the receptor. Anti-idiotypic antibodies against antibodies to insulin inhibited the binding of 125I-labeled insulin to isolated rat epididymal fat cells, whereas anti-idiotypic antibodies raised against antibodies to RBP had no effect. Furthermore, on interacting with young rat thymocytes, anti-idiotypic antibodies against antibodies to insulin stimulated the uptake by the cells of α-aminoisobutyric acid, thereby mimicking the effect of insulin. These results suggest that in some cases anti-idiotypic antibodies may be useful tools in elucidating structure-function relationships for cell-membrane receptors.

Morphological and histochemical analyses of two human T-cell subpopulations bearing receptors for IgM or IgG.

Abstract: Two subpopulation of circulating human T cells forming rosettes with neuraminidase-treated sheep erythrocytes were purified on the basis of the presence of receptors for IgG (TG cells) or for IgM (TM cells), and were shown to have distinguishing morphological and histochemical characteristics. TM cells had the general features of typical small- or medium-sized lymphocytes; most were easily identifiable by distinctive cytoplasmic accumulations, usually one and sometimes two large spots, of nonspecific acid esterase activity. The release of the vesicular contents on short-term culture of TG cells was inhibited by cytochalasin B. Definition of these distinguishing characteristics of TM and TG cells provides a basis for practical enumeration of these functionally distinct subpopulations of human T cells. Some of the TG cells were capable of endocytosis of IgG antibody-coated erythrocytes.

Expression and function of idiotypes of lymphocytes.

Abstract: Publisher Summary This chapter summarizes a series of new procedures for the production of anti-idiotypic reagents. It discusses the serological analysis of antigen receptors on lymphocytes and discusses the functional aspects of lymphocyte receptor idiotypes within an immune network. Cross-idiotypic specificity was observed between human cold agglutinins of different individuals between a mouse myeloma protein with specificity for phosphorylcholine and antibodies induced in mice with this antigen among antibodies to streptococcal carbohydrates from different rabbits and between human anti-γ-globulins. Idiotypic cross-reactions between immunoglobulin molecules from more than one source promoted a series of studies on the structural requirements for the expression of idiotypic determinants. Idiotypic determinants of the antigen-specific receptors of lymphocytes are discussed in this chapter with respect to their structural and serological definition as well as to their possible functional role in immune regulation. The serological basis of idiotypes on lymphocytes is established with anti-idiotypic antisera to total “idiotypes” as well as to idiotypic subspecificities such as V H - and V L -associated idiotypic determinants and binding site- or framework-associated idiotypic determinants. Lymphocyte receptor idiotypes play a fundamental role in immune regulation. Within one individual's immune system, spontaneous auto-anti-idiotypic antibodies can be observed.

Evidence That the Malignant Lymphoma of Sjögren's Syndrome Is a Monoclonal B-Cell Neoplasm

Abstract: We studied the malignant lymphomas that developed in patients with Sjogren's syndrome and the antecedent benign salivary-gland lesions to determine their cellular characteristics. We used an immunoperoxidase technic that identified intracellular gamma, alpha and mu heavy chains and kappa and lambda light chains. In six of nine patients, the lymphomas were composed of cells containing intracytoplasmic immunoglobulin that was exclusively IgMK. The benign lymphoepithelial salivary-gland lesions preceding these malignant tumors consisted of approximately equal numbers of lymphoid cells containing either kappa or lambda light chains. Thus, in some patients with Sjogren's syndrome, there may be a progression in the lympho-proliferative lesions from a polyclonal infiltrate to a monoclonal neoplasm. Intracytoplasmic immunoglobulin identifies six of the nine cases as being B-cell in origin.

Type B Hepatitis after Needle-Stick Exposure: Prevention with Hepatitis B Immune Globulin: Final Report of the Veterans Administration Cooperative Study

Abstract: Hepatitis B immune globulin (HBIG) and immune serum globulin (ISG) were examined in a randomized, double-blind trial to assess their relative efficacies in preventing type B hepatitis after needle-stick exposure to hepatitis B surface antigen (HBsAG)-positive donors. Clinical hepatitis developed in 1.4% of HBIG and in 5.9% of ISG recipients (P = 0.016), and seroconversion (anti-HBs) occurred in 5.6% and 20.7% of them respectively (P less than 0.001). Mild and transient side-effects were noted in 3.0% of ISG and in 3.2% of HBIG recipients. Available donor sera were examined for DNA polymerase (DNAP) and e antigen and antibody (HBeAg; anti-HBE). Both DNAP and HBeAg showed a highly statistically significant correlation with the infectivity of HBsAg-positive donors. Hepatitis B immune globulin remained significantly superior to ISG in preventing type B hepatitis even when the analysis was confined to these two high-risk subgroups. The efficacy of ISG in preventing type B hepatitis cannot be ascertained because a true placebo group was not included.

Analysis of the repertoire of anti‐NP antibodies in C57BL/6 mice by cell fusion. I. Characterization of antibody families in the primary and hyperimmune response

Abstract: Spleen cells from C57BL/6 mice sensitized to the hapten (4-hydroxy-3-nitrophenyl)acetyl (NP) were hybridized with myeloma cells, and a variety of hybrid cell lines was isolated which secreted homogeneous anti-NP antibodies. The antibodies were purified by affinity chromatography and their chain composition, affinity and fine specificity were determined. All antibodies recovered from the primary immune response carried λ light and μ or γ1 heavy chains. Their variable portions were nonidentical but similar in terms of hapten-binding specificity with a higher affinity for the cross-reacting haptens (4-hydroxy-3,5-dinitro-phenyl)acetyl (NNP) and (4-hydroxy-5-iodo-3-nitro-phenyl)acetyl (NIP) than for the homologous hapten NP. This heteroclitic property as well as the presence of λ, μ and γ1 chains are characteristic for primary anti-NP sera of C57BL/6 mice. In contrast, four families of anti-NP antibodies, each with a characteristic fine specificity pattern, were found among the hybrid cell antibodies derived from the hyperimmune anti-NP response. The antibodies of one of these families were related to the antibodies recovered from the primary immune response in that they were heteroclitic and carried λ light chains. All members of the other groups expressed k chains and were nonheteroclitic. The finding of well-defined antibody families in this system and the isolation of their members enable us to approach the problem of V gene expression and diversification in a new way.

Two-gene control of the expression of a murine Ia antigen.

Abstract: Two dimensional polyacrylamide gel electrophoresis of Non-Idet P-40 extracts and of specific Ia immunoprecipitates from [35S]methionine-labeled mouse spleen lymphocytes has revealed that the cell surface expression of some Ia antigens appears to be controlled by two genes. One locus, which maps in the I-A subregion, is probably the structural gene for an Ia polypeptide chain. The second locus, which maps between the I-J and H-2D regions, controls whether this I-A encoded molecule (Ae) remains in the cytoplasm or is modified and expressed on the cell surface. Complementation between these two loci allowing surface expression of Ae can occur in the cis or trans chromosomal position. Both the I-A molecule and a polypeptide chain coded for by a locus in I-E are coprecipitated by anti-I-E antibodies, suggesting that these two chains are associated with each other as a multisubunit complex in the cell. Because the ability to complement I-A for Ae expression is a property only of those strains which synthesize an I-E-encoded protein, it is likely that the I-E product itself is regulating the expression of Ae. These observations suggest several mechanisms by which interaction between two I region loci can generate new cell surface molecules. As a result, they may have important implications for understanding the molecular basis of two gene control of immune responsiveness and immune suppression.

Interspecies spleen-myeloma hybrid producing monoclonal antibodies against mouse lymphocyte surface glycoprotein, T200.

Abstract: A cell hybrid has been selected from fusion of a mouse myeloma and rat spleen cells immunized against mouse lymphoma cells that produces monoclonal antibody against the mouse lymphocyte surface glycoprotein, T200. Antibody binding assays employing the monoclonal antibody show that there are about 50,000-100,000 molecules of T200 glycoprotein on mouse thymocytes and that similar antigens are present on spleen and bone marrow but not detected on nonlymphoid tissues. Examination of the labeled molecules precipitated from detergent extracts of spleen cells and thymocytes iodinated by the lactoperoxidase technique by SDS-PAGE confirm that there are structural differences between the antigens found on B and T lymphocytes. The B-cell glycoprotein consists of at least one component of apparent mol wt 220,000 on SDS-PAGE, while the T-cell glycoprotein has an apparent mol wt of about 190,000.

Selective induction of an immune response in human external secretions by ingestion of bacterial antigen.

Abstract: Ingestion of capsules which contained killed Streptococcus mutans by four healthy human subjects led to the appearance of specific antibodies in external secretions. Salivary and lacrymal antibodies were detected within 1 wk of ingestion and continued to increase throughout a 14-day immunization period, with a gradual decline during the 2 ensuing months. A second period of immunization resulted in a pronounced increase of specific antibody levels which occurred earlier than in the primary immunization period and reached peak levels by day 10. No change was detected in serum antibody levels throughout either immunization period. The antibody activity in all secretions was associated with the immunoglobulin A class, as determined by immunochemical analyses. These data indicate that ingestion of bacterial antigens selectively stimulates the immune response in secretions.

Increased Spontaneous Polyclonal Activation of B Lymphocytes in Mice with Spontaneous Autoimmune Disease

Abstract: Early in life, mice of four kinds [NZB, (NZB X NZW)F1, MRL/1, and male BXSB] with autoimmune disease spontaneously produced far more (greater than 3 S.D.) anti-hapten antibody-forming cells in spleens and greater concentrations of anti-hapten antibodies in sera than immunologically normal strains of mice (AKR, BALB/c, C57BL/6, DBA/1-J, DBA/2J, LG/J, 129, NZW, and female BXSB). This increased nonspecific antibody production by the abnormal animals' B cells correlated well with the spontaneous development of anti-single-stranded DNA antibodies, but not with serum levels of the viral envelope glycoprotein, gp70. These results suggest that the spontaneous formation of autoantibodies in mice whose immunologic disorder is manifested by a lupus-like disease may result from polyclonal activation of B cells by endogenous or exogenous B cell activators.

Function of circulating antibody to acetylcholine receptor in myasthenia gravis Investigation by plasma exchange

Abstract: Plasma exchange has been used to investigate the function fo anti-acetylcholine receptor (anti-AChR) antibody in seven patients with acquired myasthenia gravis (MG) who had elevated antibody titers and in one patient with congenital MG who had normal titers. There was an inverse association between clinical indices of muscle strength and anti-AChR titers, with a minimum time lag of 2 days for the clinical response. The inverse association of the clinical state with anti-AChR antibody titers was closer than that with total immunoglobulin G or other immunoglobulins, and is consistent with the view that the anti-AChR antibody is the principal factor interfering with neuromuscular transmission in acquired MG.

T-lymphocyte heterogeneity in the rat: separation of functional subpopulations using a monoclonal antibody.

Abstract: W3/25 antibody is the monoclonal product of a hybrid cell resulting from the fusion of a mouse myeloma cell line with spleen cells from a mouse immunized with rat thymocytes. Pure clones have been derived, and segregants free of parental myeloma chains have been isolated. Previous studies have shown that this antibody recognizes a subpopulation of T cells among rat thoracic duct lymphocytes. In the work reported here, three T-cell functions were assayed after separating rat thoracic duct lymphocytes on the fluorescence-activated cell sorter on the basis of labeling with W3/25 antibody. Two of the functional activities appeared to be completely segregated by this procedure. Thus, helper cell activity for an anti-hapten plaque-forming cell response was confined to the labeled population, whereas the allogeneic suppressive effect produced in a parental vector F1 adoptive transfer was mediated by cells in the unlabeled fraction. The third function, graft-versus-host activity, was almost entirely contained within the labeled subpopulation. It is concluded that the antigenic determinant recognized by the monoclonal antibody W3/25 is a differentiation marker for T-cell functional subpopulations.

Idiotype-specific T helper cells are required to induce idiotype-positive B memory cells to secrete antibody.

Abstract: We have tested the proposition that induction of certain sets of B cell clones to produce antibody requires a signal from T helper cells that recognize idiotypic determinants expressed on Ig receptors of the relevant B cell clones. The approach is based on the analysis of T cell populations required to induce B cells to secrete anti-arsonate antibodies that are marked by a cross-reactive idiotype (CRId). CRId+ anti-azophenyl arsonate (Ar) antibodies are produced in A/J strain mice after immunization with Ar keyhole limpet hemocyanin and represent 20–70% of the total anti-Ar antibody response. These studies indicate that antibody secretion by idiotype+ B memory cells requires two signals: one provided by “carrier”-specific Ly-1 cells, and a second delivered by idiotype-specific Ly-1 cells. Both signals are required for optimal induction of idiotype+ B memory clones.

Antibody to nuclear ribonucleoprotein penetrates live human mononuclear cells through Fc receptors

Abstract: IT is commonly accepted that antibodies do not penetrate living cells. In only one study anti-purine and anti-nucleoside antibodies were found to penetrate fertilised sea urchin eggs and modify their development1. Such penetration has been considered unusual and the addition of anti-DNA antibodies does not affect mammalian tissue cells in culture2. Direct immunofluorescence of skin biopsies of patients with mixed connective tissue disease (MCTD) using fluorescent anti-IgG has occasionally shown speckled intranuclear fluorescence3–5 but it is doubted that IgG entered the cells while still viable. Patients with MCTD have high titres of antibody to nuclear ribonucleoprotein (RNP)6,7 which also gives a nuclear speckled pattern on cell substrates in direct immunofluorescence8. Should the antibodies to cellular components and nucleic acids which occur in autoimmune diseases be able to penetrate living cells, a novel mechanism of immunologically mediated damage and/or dysfunction could operate. We show here that anti-RNP IgG can penetrate viable human mononuclear cells (MNC), by their surface Fc receptor, and react with their nuclear RNP.

Monoclonal antibody to a human histocompatibility alloantigen, HLA-A2.

Abstract: ANTIGENS of the HLA-A, -B, -C and -DR series have been defined mainly using sera from multiparous women1, which generally are comparatively weak, serologically complex and available in only limited quantities. Furthermore, large screening programmes are required to find usable sera, especially for rare specificities. Although antisera to HLA determinants can be produced in high titres by immunising animals of various species with purified HLA-A, -B, -C, -D antigens2–5, they usually require extensive absorption to reveal polymorphic specificity and so have not so far been used as routine tissue-typing reagents. The development of techniques for producing hybrid cell lines secreting monoclonal antibodies of defined specificity6,7, provides a way of circumventing the problems of generating human polymorphic antisera by heteroimmunisation and has already been used to produce a monoclonal antibody against the human blood group A determinant8. Here we describe the production of a cell line secreting an anti-HLA-A2 antibody.