Showing papers on "Antigen published in 1986"

Selective rejection of H–2-deficient lymphoma variants suggests alternative immune defence strategy

Abstract: Metazoan organisms may discriminate between self and non-self not only by the presence of foreign antigens but also by the absence of normal self markers. Mammalian adaptive immune responses use the first strategy, with the additional requirement that foreign antigens are recognized in the context of self-major histocompatibility complex (MHC) products at the cell surface. Aberrant cells which fail to express MHC products adequately can therefore avoid detection. A more primitive but complementary defence system, eliminating such cells on the basis of absent self-markers, is suggested by a re-interpretation of phenomena associated with metastasis and natural resistance. We now show that murine lymphoma cells selected for loss of H-2 expression are less malignant after low-dose inoculation in syngeneic hosts than are wild-type cells, and that the rejection of such cells is non-adaptive. On the basis of our data, we suggest that natural killer cells are effector cells in a defence system geared to detect the deleted or reduced expression of self-MHC.

Complementary DNA for a novel human interleukin (BSF-2) that induces B lymphocytes to produce immunoglobulin

Abstract: When stimulated with antigen, B cells are influenced by T cells to proliferate and differentiate into antibody-forming cells. Since it was reported that soluble factors could replace certain functions of helper T cells in the antibody response, several different kinds of lymphokines and monokines have been reported in B-cell growth and differentiation. Among these, human B-cell differentiation factor (BCDF or BSF-2) has been shown to induce the final maturation of B cells into immunoglobulin-secreting cells. BSF-2 was purified to homogeneity and its partial NH2-terminal amino-acid sequence was determined. These studies indicated that BSF-2 is functionally and structurally unlike other known proteins. Here, we report the molecular cloning, structural analysis and functional expression of the cDNA encoding human BSF-2. The primary sequence of BSF-2 deduced from the cDNA reveals that BSF-2 is a novel interleukin consisting of 184 amino acids.

Overlapping patterns of activation of human endothelial cells by interleukin 1, tumor necrosis factor, and immune interferon.

Abstract: We have used the quantitative binding of murine monoclonal antibodies to the surface of cultured human umbilical vein endothelial (HUVE) cells to study the responses of HUVE cells to three different immune mediators: interleukin 1 (IL 1), tumor necrosis factor (TNF), and immune interferon (IFN-gamma) Antibody H4/18, reactive with an endothelial cell-specific activation antigen, does not bind to unstimulated HUVE cells but shows rapidly and transiently inducible binding (peak 4 to 6 hr) to cells stimulated by IL 1 or TNF that declines to basal levels by 24 hr, even in the continued presence of mediator Binding of H4/18 is unaffected by IFN-gamma Antibody RR1/1, reactive with intercellular adhesion molecule 1, binds to unstimulated HUVE cells, but binding is rapidly increased (plateau 24 hr) after stimulation by IL 1 or TNF and slowly increased (over several days) by IFN-gamma In contrast to H4/18 binding, the increase in RR1/1 binding is sustained in the continued presence of mediator Antibody W6/32, reactive with HLA-A,B antigens, binds to unstimulated HUVE cells and shows gradually progressive increases (over several days) in binding upon treatment with IFN-gamma or TNF These observations demonstrate that HUVE cells show distinct but overlapping patterns of antigenic modulation in response to three different lymphokines, and suggest that the "activation" of endothelial cells observed in situ may represent a complex integration of several lymphokine-mediated signals

Regional accumulations of T cells, macrophages, and smooth muscle cells in the human atherosclerotic plaque.

Abstract: The cellular composition of human atherosclerotic plaques was analyzed by immunologic techniques. Plaques were removed from the internal carotid artery during surgery, and a panel of monoclonal antibodies was used to identify cell types. Macrophages stained by Anti-Leu-M3 were found throughout the plaque, particularly in the lipid core region, where 60% of the cells reacted with this antibody. T cells expressing the T3 antigen were most abundant in the fibrous cap, where they constituted 20% of the cell population. T cells were also isolated from the plaque and detected by a rosetting test; many of these T cells were activated, as indicated by the expression of HLA-DR. Other types of leukocytes were uncommon in the plaque. An antibody to the intermediate filament protein, desmin, was used as a marker for smooth muscle cells since some, but not all, vascular smooth muscle cells contain this protein. The desmin-positive cells were uncommon in the nonatherosclerotic intima but were more numerous in the plaque. In conclusion, atherosclerotic plaques are heterogeneous with respect to cellular composition. The smooth muscle cell dominates in the fibrous cap, which also contains many T cells; the lipid core is dominated by macrophages. We suggest that interactions between smooth muscle cells and blood-borne cells are important in the pathogenesis of atherosclerosis.

Three-dimensional structure of an antigen-antibody complex at 2.8 A resolution

Abstract: The 2.8 A resolution three-dimensional structure of a complex between an antigen (lysozyme) and the Fab fragment from a monoclonal antibody against lysozyme has been determined and refined by x-ray crystallographic techniques. No conformational changes can be observed in the tertiary structure of lysozyme compared with that determined in native crystalline forms. The quaternary structure of Fab is that of an extended conformation. The antibody combining site is a rather flat surface with protuberances and depressions formed by its amino acid side chains. The antigen-antibody interface is tightly packed, with 16 lysozyme and 17 antibody residues making close contacts. The antigen contacting residues belong to two stretches of the lysozyme polypeptide chain: residues 18 to 27 and 116 to 129. All the complementarity-determining regions and two residues outside hypervariable positions of the antibody make contact with the antigen. Most of these contacts (10 residues out of 17) are made by the heavy chain, and in particular by its third complementarity-determining region. Antigen variability and antibody specificity and affinity are discussed on the basis of the determined structure.

Binding of HTLV-III/LAV to T4+ T cells by a complex of the 110K viral protein and the T4 molecule.

Abstract: Human T-lymphotropic virus type III (HTLV-III) or lymphadenopathy-associated virus (LAV) is tropic for human T cells with the helper-inducer phenotype, as defined by reactivity with monoclonal antibodies specific for the T4 molecule. Treatment of T4+ T cells with monoclonal antibodies to T4 antigen blocks HTLV-III/LAV binding, syncytia formation, and infectivity. Thus, it has been inferred that the T4 molecule itself is a virus receptor. In the present studies, the surfaces of T4+ T cells were labeled radioactively, and then the cells were exposed to virus. After the cells were lysed, HTLV-III/LAV antibodies were found to precipitate a surface protein with a molecular weight of 58,000 (58K). By blocking and absorption experiments, this 58K protein was identified as the T4 molecule. No cell-surface structures other than the T4 molecule were involved in the antibody-antigen complex formation. Two monoclonal antibodies, each reactive with a separate epitope of the T4 molecule, were tested for their binding capacities in the presence of HTLV-III/LAV. When HTLV-III/LAV was bound to T4+ T cells, the virus blocked the binding of one of the monoclonal antibodies, T4A (OKT4A), but not of the other, T4 (OKT4). When HTLV-III/LAV was internally radiolabeled and bound to T4+ T cells which were then lysed, a viral glycoprotein of 110K (gp110) coprecipitated with the T4 molecule. The binding of gp110 to the T4 molecule may thus be a major factor in HTLV-III/LAV tropism and may prove useful in developing therapeutic or preventive measures for the acquired immune deficiency syndrome.

CD8+ lymphocytes can control HIV infection in vitro by suppressing virus replication

Abstract: Lymphocytes bearing the CD8 marker were shown to suppress replication of human immunodeficiency virus (HIV) in peripheral blood mononuclear cells. The effect was dose-dependent and most apparent with autologous lymphocytes; it did not appear to be mediated by a cytotoxic response. This suppression of HIV replication could be demonstrated by the addition of CD8+ cells at the initiation of virus production as well as after several weeks of virus replication by cultured cells. The observations suggest a potential approach to therapy in which autologous CD8 lymphocytes could be administered to individuals to inhibit HIV replication and perhaps progression of disease.

Identification of a putative second T-cell receptor.

Abstract: Framework monoclonal antibodies have identified a population of human lymphocytes that express the T3 glycoprotein but not the T-cell receptor (TCR) alpha- and beta-subunits. Chemical crosslinking experiments reveal that these lymphocytes express novel T3-associated polypeptides, one of which appears to be the product of the T gamma gene. The other polypeptide may represent a fourth TCR subunit, designated T delta.

The Molecular Genetics of the T-Cell Antigen Receptor and T-Cell Antigen Recognition

Abstract: The genes encoding the alpha and beta chain of the T-cell receptor and the gamma gene have been cloned, and their structure, organization, ontogeny of expression, pattern of rearrangement, and diversification are now generally understood. In most cases, the immunoglobulin paradigm applied very well to the corresponding phenomena in T cells, although as described above, some interesting and potentially important differences exist. Nevertheless, there are still many unanswered questions regarding the ontogeny and mechanism of MHC-restricted antigen recognition, and it is not clear how far the immunoglobulin model can take us in understanding these phenomena. Although the alpha/beta heterodimer looks like an antibody and the binding sites of the two molecules may be similar, the rules governing B- and T-cell activation are clearly different, and the ligand(s) bound by the receptor are still poorly characterized. In the future, T-cell receptor genes, as well as those encoding the T-cell accessory molecules, will be altered in vitro and transferred into mammalian cells in culture and into whole organisms in an attempt to understand T-cell antigen recognition. These tools will allow us to manipulate the mammalian immune response in a variety of different ways that will have a profound impact both on our understanding of immunology and on medicine in the future.

Macrophage heterogeneity in the rat as delineated by two monoclonal antibodies MRC OX-41 and MRC OX-42, the latter recognizing complement receptor type 3.

Abstract: Two monoclonal antibodies, designated MRC OX-41 and MRC OX-42, have been shown to label subsets of macrophages. Using immunoperoxidase and immunofluorescence analysis, tissue macrophages were shown to be heterogeneous with respect to binding of MRC OX-41 and MRC OX-42 antibodies. Although both antibodies labelled subsets of macrophages, the antibodies also reacted with granulocytes and dendritic cells. The antigens recognized by these antibodies were identified by metabolic and cell surface labelling followed by immunoprecipitation and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). MRC OX-41 recognized a surface protein of 110,000-120,000 MW, while MRC OX-42 immunoprecipitated three polypeptides with molecular weights of 160,000, 103,000 and 95,000. The Fab fragment of MRC OX-42 antibody inhibited complement-mediated rosette formation between sensitized erythrocytes and rat macrophages and granulocytes. Membrane molecules with similar biochemical and functional properties to MRC OX-42 antigen have been identified in mouse and man as the receptors for iC3b, and it is probable that MRC OX-42 antibody recognizes the rat homologue of the receptors in these other species.

The Role of the T3/Antigen Receptor Complex in T-Cell Activation

Abstract: The results of several studies demonstrate that activation of resting T-cells requires two stimuli (1–4). One stimulus is represented by the recognition of antigen in conjunction with MHC gene products by the T-cell antigen receptor. The second stimulus is represented by accessory cells and their products. The delineation of the T-cell receptor for antigen and it’s associated molecules, T3, allows a study of how stimuli transmitted through these molecules signal activation. We present here some of these studies. To perform them, we have used the human T-cell line, Jurkat.

Induction of CD4-dependent cell fusion by the HTLV-III/LAV envelope glycoprotein.

Abstract: Formation of syncytia, with progression to cell death, is a characteristic feature of in vitro cultures of susceptible cells infected with human T-lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV)1–3. Viral antigen-positive multi-nucleated giant cells have also been observed in histological sections from infected individuals4,5. In vitro, formation of these multinucleated giant cells occurs through cell fusion which is dependent on cell-surface expression of the differentiation antigen CD4 (ref. 1). Utilizing a recombinant vaccinia virus containing the gene for the envelope glycoprotein of HTLV-III/LAV6, we demonstrate that cell-surface expression of this protein, in the absence of other HTLV-III/LAV structural or regulatory proteins, is sufficient to induce CD4-dependent cell fusion, leading to cell death, one of the characteristic manifestations of AIDS (acquired immune deficiency syndrome) virus cytopathology. This process may contribute to the loss of CD4+ T cells seen in AIDS.

A neuronal antigen in the brains of Alzheimer patients.

Abstract: A monoclonal antibody was prepared against pooled homogenates of brain tissue from patients with Alzheimer's disease. This antibody recognizes an antigen present in much higher concentration in certain brain regions of Alzheimer patients than in normal brain. The antigen appears to be a protein present in neurons involved in the formation of neuritic plaques and neurofibrillary tangles, and in some morphologically normal neurons in sections from Alzheimer brains. Partial purification and Western blot analysis revealed the antigen from Alzheimer brain to be a single protein with a molecular weight of 68,000. Application of the same purification procedure to normal brain tissue results in the detection of small amounts of a protein of lower molecular weight.

The LY‐1B Cell Lineage

Abstract: The murine Ly-I lymphocyte surface glycoprotein was defined initially with conventional antisera in cytotoxic assays (Cantor & Boyse 1977). As such, it appeared to be expressed exclusively on helper T cells (Cantor & Boyse 1975). Later, however. Fluorescence Activated Cell Sorter (FACS) analyses and sorting studies with monoclonal antibody reagents showed that all T cells express Ly-1, regardless of functional subclass (Ledbetter et al. 1980). Furthermore, these studies (Lanier et al. 1981a, 1981b) showed that Ly-1 is expressed on several murine B cell tumors and introduced evidence suggesting that this glycoprotein may also expressed on a small proportion of normal murine splenic B cells (Manohar et al. 1982, Hayakawa et al. 1983). Similar studies with human lymphocytes demonstrated the homologous {LeuI) cell surface antigen on all normal T cells (Ledbetter et al. 1981), on some B cell tumors (particularly chronic lymphocytic leukemias) (Martin et al. 1981) and, as in the mouse, on a small proportion of apparently normal B cells (CalligarisCappio et al. 1982). Thus, a series of earlier findings foreshadowed contemporary evidence demonstrating Ly-I and Leu-1, respectively, on subsets of murine and human B cells and showing further that Ly-1 marks functionally distinct B cells that play a major role in autoimmunity in the mouse. In this paper, we summarize the physical and functional characteristics that distinguish Ly-1 B cells from the majority of splenic and lymph node (conventional) B cells. We focus on data from cell transfer and antibody treatment studies, which locate Ly-I B cells in a separate developmental lineage that branches off from the conventional lymphocyte developmental lineage during prenatal or early neonatal life. We then consider various genetic defects that influence autoantibody production and Ly-I B representation and, finally, we discuss potential homolog-

Transfer of specificity by murine alpha and beta T-cell receptor genes.

Abstract: T-cell receptor alpha- and beta-chain genes were isolated from a class I major histocompatibility complex-restricted cytotoxic T-cell clone and transferred by protoplast fusion into another cytolytic T-cell clone of different specificity. Expression of the transfected alpha and beta genes endowed the recipient cell with the specificity of the donor cell.

Functional subsets of human helper-inducer cells defined by a new monoclonal antibody, UCHL1.

Abstract: The monoclonal antibody UCHL1 identified an antigen present on most thymocytes, a subpopulation of resting T cells within both the CD4 and CD8 subsets, and on mature activated T cells. The UCHL1 determinant is also present on cells of the myeloid lineage, but not normal B cells or NK cells. Functionally, UCHL1 identifies a subpopulation of T cells which proliferates maximally to soluble antigen and provides maximum help for PWM-stimulated immunoglobulin synthesis. In contrast, the UCHL1- cells do not induce immunoglobulin synthesis and do not proliferate in the presence of soluble antigen, although both the UCHL1- and the UCHL1+ fractions of T cells proliferate well in the presence of PHA. By standard immunoprecipitation techniques and SDS page, the antigen recognized by UCHL1 was found to have a molecular weight of 180,000-185,000. Preclearing experiments using antibodies identifying the leucocyte common antigen, LCA, and the lymphocyte function-associated antigen, LFA-1, which have similar molecular weights to UCHL1, showed that the UCHL1 determinant is not biochemically related to these antigens.

Long-term cultures of HTLV-III--infected T cells: a model of cytopathology of T-cell depletion in AIDS.

Abstract: Long-term cultures were established of HTLV-III-infected T4 cells from patients with the acquired immune deficiency syndrome (AIDS) and of T4 cells from normal donors after infection of the cells in vitro. By initially reducing the number of cells per milliliter of culture medium it was possible to grow the infected cells for 50 to 60 days. As with uninfected T cells, immunologic activation of the HTLV-III-infected cells with phytohemagglutinin led to patterns of gene expression typical of T-cell differentiation, such as production of interleukin-2 and expression of interleukin-2 receptors, but in the infected cells immunologic activation also led to expression of HTLV-III, which was followed by cell death. The results revealed a cytopathogenic mechanism that may account for T4 cell depletion in AIDS patients and suggest how repeated antigenic stimulation by infectious agents, such as malaria in Africa, or by allogeneic blood or semen, may be important determinants of the latency period in AIDS.

Differences in antigen presentation to MHC class I-and class II-restricted influenza virus-specific cytolytic T lymphocyte clones.

Abstract: We have examined requirements for antigen presentation to a panel of MHC class I-and class II-restricted, influenza virus-specific CTL clones by controlling the form of virus presented on the target cell surface. Both H-2K/D- and I region-restricted CTL recognize target cells exposed to infectious virus, but only the I region-restricted clones efficiently lysed histocompatible target cells pulsed with inactivated virus preparations. The isolated influenza hemagglutinin (HA) polypeptide also could sensitize target cells for recognition by class II-restricted, HA-specific CTL, but not by class I-restricted, HA-specific CTL. Inhibition of nascent viral protein synthesis abrogated the ability of target cells to present viral antigen relevant for class I-restricted CTL recognition. Significantly, presentation for class II-restricted recognition was unaffected in target cells exposed to preparations of either inactivated or infectious virus. This differential sensitivity suggested that these H-2I region-restricted CTL recognized viral polypeptides derived from the exogenously introduced virions, rather than viral polypeptides newly synthesized in the infected cell. In support of this contention, treatment of the target cells with the lysosomotropic agent chloroquine abolished recognition of infected target cells by class II-restricted CTL without diminishing class I-restricted recognition of infected target cells. Furthermore, when the influenza HA gene was introduced into target cells without exogenous HA polypeptide, the target cells that expressed the newly synthesized protein product of the HA gene were recognized only by H-2K/D-restricted CTL. These observations suggest that important differences may exist in requirements for antigen presentation between H-2K/D and H-2I region-restricted CTL. These differences may reflect the nature of the antigenic epitopes recognized by these two CTL subsets.

AIDS retrovirus induced cytopathology: giant cell formation and involvement of CD4 antigen

Abstract: The formation of multinucleated giant cells with progression to cell death is a characteristic manifestation of the cytopathology induced by the AIDS retrovirus in infected T lymphoid cells. The mechanism of giant cell formation was studied in the CD4 (T4/Leu 3) positive T cell lines JM (Jurkat) and VB and in variants of these lines that are negative for cell surface CD4 antigen. By means of a two-color fluorescent labeling technique, multinucleated giant cells in infected cultures were shown to form through cell fusion. Antibody to CD4 specifically inhibited fusion, and uninfected CD4 negative cells, in contrast to uninfected CD4 positive cells, did not undergo fusion with infected cells, suggesting a direct role for the CD4 antigen in the process of syncytium formation. These results suggest that, in vivo, cell fusion involving the CD4 molecule may represent a mechanism whereby uninfected cells can be incorporated into AIDS virus infected syncytia. Because the giant cells die soon after they are formed, this process may contribute to the depletion of helper/inducer T cells characteristically observed in AIDS.

Tumor rejection antigens of chemically induced sarcomas of inbred mice.

Abstract: Chemically induced sarcomas of inbred mice are immunogenic in syngeneic hosts, and preimmunization with tumor cells leads to resistance to subsequent tumor transplants. The tumor rejection antigens (TRAs) that mediate this reaction are highly specific for each tumor; cross-protection between different syngeneic sarcomas is rare. Isolated membrane and cytosol fractions from two antigenically distinct BALB/c sarcomas, Meth A and CMS5, have TRA activity, and biochemical characterization of the active components from the cytosol and plasma membranes of these two tumors identified a glycoprotein of Mr 96,000. Immunization with unfractionated Meth A cytosol frequently leads to tumor enhancement, but the tumor-enhancing activity (TEA) is lost on fractionation and TRA activity becomes demonstrable. As Meth A and CMS5 lack expression of murine leukemia virus (MuLV) antigens or transcripts, MuLV-related antigens cannot be involved in the TEA or TRA activities of these tumors. In contrast to the lack of cross-reactivity between Meth A and CMS5 TRAs in transplantation tests, rabbit antiserum prepared against the Meth A Mr 96,000 antigen reacted with the CMS5 Mr 96,000 antigen. In view of the biochemical and antigenic similarities of Meth A and CMS5 TRAs, we propose that structurally related but distinct Mr 96,000 glycoproteins are expressed in chemically induced sarcomas and that these molecules are responsible for the individually specific immunogenicity of these tumors.

Isolation of human-p53-specific monoclonal antibodies and their use in the studies of human p53 expression

Abstract: The isolation and construction of a complete human p53 cDNA and subsequent expression in monkey cells is described. A set of new anti-(human p53) monoclonal antibodies has also been obtained and used to show the expression of the human p53 cDNA in cos-l cells. These antibodies enable the specific detection of human p53, which is synthesised in the presence of p53 from other species. Fusion proteins of p53 with beta-galactosidase were used firstly as antigen and secondly, in conjunction with competition assays, to localise the determinants recognized by the antibodies. At least two previously unrecognized epitopes are involved and two of the antibodies are human-p53-specific. The epitopes are denaturation-resistant and the antibodies are, therefore, valuable for immunoblotting as well as immunoprecipitation and enzyme-linked immunoassay. Transfection of plasmids containing complete human p53 cDNA into monkey (cos-l) cells cause expression of human p53 recognized by the monoclonal antibodies. Control plasmids did not induce immunoreactive protein.

Antigen-driven selection of virgin and memory B cells.

Abstract: This review has summarized the evidence indicating that far more B cells are produced in adult bone marrow than are required to maintain B cell numbers in the periphery. It is shown that most if not all these newly-formed B cells have the potential to become mature peripheral B cells. However, to do this they need to receive an appropriate signal in secondary lymphoid organs. Cells failing to receive such a signal die after a brief period. Two separate situations have been identified which result in recruitment of newly-formed virgin B cells into the peripheral B-cell pool: Following activation by antigen. When the peripheral B-cell pool has been depleted. It is proposed that the first of these signals requires T help and is initiated by antigen presented on interdigitating cells in extrafollicular areas of secondary lymphoid organs. This process seems to be confined to periods immediately following administration of antigen and does not continue in established immune responses to thymus-dependent antigens. It seems probable that continued B cell activation, occurring during long term antibody responses, takes place in the follicles of secondary lymphoid organs and is driven by antigen presented on follicular dendritic cells. Indirect evidence is cited which suggests that somatic mutation in rearranged immunoglobulin V-region genes occurs mainly following B-cell activation in follicles and not during primary B lymphopoiesis. It is suggested that this may involve a hypermutation process which is switched on in activated B cells in germinal centers. Evidence is presented suggesting that plasma cells generated from B cells activated early in immune responses have an average life-span of less than 3 d. However, plasma cells generated in established responses appear to have an average life-span in excess of 20 d. Later sections in the review consider how B-cell recruitment in thymus-independent antibody responses differs markedly from recruitment during thymus-dependent responses. The possible role of splenic marginal zone B cells in some thymus-independent antibody responses is discussed and the evidence indicating that SIgM + ve, IgD-ve marginal zone B cells develop as a distinct population from recirculating SIgM + ve, IgD + ve B cells is summarized.

Release of Prostaglandin D2 into Human Airways during Acute Antigen Challenge

Abstract: Among the many possible mediators of the early asthmatic response, prostaglandin D2, a bronchoconstrictor, is the principal cyclooxygenase metabolite of arachidonic acid that is released upon the activation of mast cells and is also synthesized by human alveolar macrophages. We performed bronchoalveolar lavage in five patients with chronic stable asthma, before and up to nine minutes after local provocative challenge with Dermatophagoides pteronyssinus. The lavage fluid was analyzed for products of arachidonic acid metabolism. Prostaglandin D2 levels in all five patients rose an average of 150-fold, from less than 8 to 332 +/- 114 pg per milliliter (mean +/- SEM; P less than 0.050), after local instillation of the antigen. Levels of 15-hydroxyeicosatetraenoic acid, which may also have a role in the pulmonary allergic response, were detectable in lavage fluid before challenge and increased after provocation with the antigen in four of the five patients. The activity of beta-glucuronidase, an enzyme released by macrophages and mast cells upon stimulation, tended to increase in the lavage fluid after provocation in all patients. These studies provide evidence that the release of prostaglandin D2 into the airways is an early event after the instillation of D. pteronyssinus in patients who are sensitive to this antigen.

Impaired assembly and transport of HLA-A and -B antigens in a mutant TxB cell hybrid.

Abstract: Biosynthesis of HLA class I antigens has been studied in a variant B-LCLxT-LCL hybrid, 174XCEM.T2. This cell line encodes HLA-A2 and -B5, but expresses only small amounts of A2 antigen and undetectable B5 antigen at the cell surface due to a mutation inactivating a trans-acting regulatory gene encoded within the class II region of the human major histocompatibility complex. Northern blot analysis with HLA-A- and HLA-B-specific probes shows that 174XCEM.T2 synthesizes quantities of A and B locus mRNA comparable with its class I antigen-positive parent cell line. Immune precipitation studies indicate that 174XCEM.T2 synthesizes normal HLA heavy chains and beta 2-microglobulin which fail to form dimers. The heavy chains are N-glycosylated normally, but processing of the glycan to the complex form does not occur. In addition, free heavy chains in this cell line are not phosphorylated. Thus, the majority of class I heavy chains in 174XCEM.T2 do not combine with beta 2-microglobulin, and are not processed or transported to the cell surface. As both subunits are synthesized in normal amounts, we propose that an additional molecule absent from 174XCEM.T2 and encoded by an HLA-linked gene is necessary for efficient assembly of class I antigen subunits.

Distribution of Oncofetal Antigen Tumor-associated Glycoprotein-72 Defined by Monoclonal Antibody B72.3

Abstract: Murine monoclonal antibody B72.3, prepared against a membrane-enriched extract of human metastatic carcinoma, was reacted with a spectrum of adult and fetal human tissues using avidin-biotin-complex immunohistochemical techniques to evaluate the expression of the reactive tumor associated glycoprotein (TAG)-72 antigen. TAG-72 was shown to be expressed in several epithelial-derived cancers including 94% of colonic adenocarcinomas, 84% of invasive ductal carcinomas of the breast, 96% of non-small cell lung carcinomas, 100% of common epithelial ovarian carcinomas, as well as the majority of pancreatic, gastric, and esophageal cancers evaluated. TAG-72 expression was not observed, however, in tumors of neural, hematopoietic, or sarcomatous derivation, suggesting that the TAG-72 antigen is "pancarcinoma" in nature. Appreciable monoclonal antibody B72.3 reactivity was generally not observed in adult normal tissues, with limited reactivity noted in a few benign lesions of the breast and colon. TAG-72 antigen expression was detected, however, in fetal colon, stomach, and esophagus, thus defining TAG-72 as an oncofetal antigen. TAG-72 has previously been shown to be distinct from carcinoembryonic antigen and other tumor associated antigens. The pancarcinoma distribution and lack of significant reactivity with normal adult tissues of monoclonal antibody B72.3 suggest its potential diagnostic and therapeutic utility for human carcinomas.

The requirement for lymphocyte function-associated antigen 1 in homotypic leukocyte adhesion stimulated by phorbol ester.

Abstract: Lymphocyte activation is accompanied by increased adhesiveness and motility. Although specific antigen may be used to stimulate increased adhesiveness, stimulated lymphocytes show a generalized increased adherence to cells lacking specific antigen. Cells cultured in the MLR acquire the ability to adhere to a wide variety of tumor cell types. There is no MHC restriction in this adhesion, although species specificity has been shown (1). Adhesion of lymphocytes to one another can also be measured as cluster formation, i.e., aggregation. After autologous MLR or periodate stimulation, 5-35% of the viable lymphocytes are found in clusters (2). Lymphocytes isolated from clusters by vigorous vortexing are found to readily reaggregate. Cluster formation is also induced by phorboi esters. Within 15 rain, human PBL show uropod formation, and within 30 min exhibit hairy surface projections, ruffled membranes, and begin aggregating (3). Similar aggregation is seen with monocytes (3) and some leukocyte cell lines, including EBV-transformed B lymphocytes (4). Both B lymphocytes and the Lyt2 + and Lyt-2- subsets of T lymphocytes have been shown to participate in cluster formation (2). Despite the obvious relevance of changes in lymphocyte adhesiveness to immune cell interactions, the cell surface molecules mediating adhesiveness by stimulated lymphocytes have not been defined. Previous studies have shown that mAbs to the lymphocyte function-associated 1 (LFA-1)I molecule inhibit the effector-target adhesion step of CTL-mediated killing (5), and a wide variety of other adhesion-dependent leukocyte functions, including antigen-specific T-B cell cooperation, antigen-specific and mitogen proliferative responses (6), natural killing, and antibody-dependent cellular cytotoxicity by K cells and granulocytes (7). Lymphocytes from patients with genetic deficiency of LFA-1 show diminished activity in adhesion-dependent functional assays (8-10). These findings suggested that LFA-1 cooperates with a number of different specific cell surface receptors in heterotypic cell-cell interactions. LFA-1 is a leukocyte cell surface glycoprotein with an c~L subunit of 180,000 Mr and/3 subunit of 95,000 Mr. Here we have investigated the role of LFA-1 in the increased adhesiveness of phorbol ester-stimulated leukocytes. Phorbol esters are analogues of diacylglycThis work was supported by Council for Tobacco Research grant 1307, National Institutes of Health grants CA31798 and AI05877, and Dr. Rothlein's National Institutes of Health fellowship AI06963. J Abbreviation used in this paper: LFA-1, lymphocyte function-associated antigen 1.