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PubMedDate not supplied

[The cluster headache: a clinical model of immunologic receptor pathology?].

It is well established that cluster headache shows impaired functions at their neuroimmunomodulatory system level. Defect in receptor expression for 5-HT, IL-1 and IL-2 have been found in these patients. Sumatriptan, a molecule with agonistic activity for 5-HT1D receptor, truncates cluster headache attacks in 74% of patients. Flow cytometric analysis of monocytes expressing 5-HT receptor in cluster headache patients showed different trends clearly correlated with the clinical response to sumatriptan. Our findings strongly support the concept that cluster headache patients who are non responders to sumatriptan could present a block in their 5-HT receptor possibly due to specific autoantibodies for this receptor site.

Adult↗
PubMed1982

The ontogeny of immunological receptors in the thymus.

Receptors for sheep erythrocytes, for the Fc part of IgG (Fc gamma R) and IgM (Fc mu R), and for components of activated human complement C3 (C3bR and C3dR) in thymus tissue from fetuses, infants and children were studied using haemadsorption to cryostat sections in a closed chamber. Sheep erythrocytes (SE) did not adhere to sections of thymus from fetuses at 10-11 weeks of gestation, adhered weakly between 14 and 20 weeks, while they adhered in a dense monolayer in older fetuses, in infants and in children, denser in the cortex than in the medulla. Ox erythrocytes (OE), sensitized with IgG to demonstrate Fc gamma R, adhered focally to both cortical and medullary areas. The adherence was more pronounced to the sections of fetal thymus than to the sections from infants and children. OE, sensitized with IgM to demonstrate Fc mu R, adhered focally to all thymus tissue sections, preferentially to the cortex. The adherence was most pronounced in fetal thymus. SE, sensitized with IgM and coated with complement, adhered to sections of fetal thymus, but the density decreased markedly during fetal life. Indicator cells demonstrating C3bR adhered focally also to sections from infants and children, while indicator cells demonstrating C3dR did not adhere to sections from individuals older than 38 weeks of gestation. Indicator cells demonstrating C3bR and C3dR adhered both to cortex and medulla.

Animals↗
PubMed1983

The use of frozen erythrocytes in macrophage studies. 2. Attachment and phagocytosis mediated by the two immunological receptors of the macrophages.

Sheep erythrocytes opsonized with IgG or C3b were frozen in various cryoprotective agents, thawed, and compared to corresponding unfrozen erythrocytes exposed to the cryoprotectants and to unfrozen erythrocytes not exposed to the cryoprotectants (controls) as test particles in macrophage attachment and phagocytosis assays. Fc-receptor-mediated attachment and phagocytosis were not influenced by the use of any cryoprotective agent tested or by freezing the erythrocytes. This was also the case with C3b-receptor-mediated attachment. Phagocytosis via this receptor was negligible in normal macrophages, but tended to be slightly more effective when the test particles had been treated with cryoprotective agents. In vitro stimulation of the macrophages with Escherichia coli endotoxin, however, triggered the capacity to internalize treated and untreated erythrocytes equally.

Animals↗
PubMed1993

The ligand binding domain of the nicotinic acetylcholine receptor. Immunological analysis.

The interaction of the acetylcholine receptor (AChR) binding site domain with specific antibodies and with alpha-bungarotoxin (alpha-BTX) has been compared. The cloned and expressed ligand binding domain of the mouse AChR alpha-subunit binds alpha-BTX, whereas the mongoose-expressed domain is not recognized by alpha-BTX. On the other hand, both the mouse and mongoose domains bind to the site-specific monoclonal antibody 5.5. These results demonstrate that the structural requirements for binding of alpha-BTX and mcAb 5.5, both of which interact with the AChR binding site, are distinct from each other.

Amino Acid Sequence↗
PubMed1999

Paul Ehrlich's passion: the origins of his receptor immunology.

In 1897, Paul Ehrlich published a selection theory of antibody formation that anticipated the theories of Jerne and Burnet by some 60 years. Ehrlich introduced into immunology the concept of the interaction of physiologically active substances with specific receptors, an idea that still dominates modern immunological thought. In this paper, we point out how Ehrlich's concept matured over 20 years, while it governed his studies in histological staining, in cell physiology, in hematology, and finally in his major contributions in experimental immunology.

Allergy and Immunology↗
PubMed1986

Mammalian beta 1- and beta 2-adrenergic receptors. Immunological and structural comparisons.

Beta 1- and beta 2-adrenergic receptors, pharmacologically distinct proteins, have been reported to be structurally dissimilar. In the present study three techniques were employed to compare the nature of mammalian beta 1- and beta 2-adrenergic receptors. Antibodies against each of the receptor subtypes were raised separately. Polyclonal antisera against beta 1-receptors of rat fat cells were raised in mice, and antisera against beta 2-receptors of guinea pig lung were raised in rabbits. Receptors purified from rat fat cells (beta 1-), S49 mouse lymphoma cells (beta 2-), and rat liver (beta 2-) were probed with these antisera. Each anti-receptor antisera demonstrated the ability to immunoprecipitate purified receptors of both beta 1- and beta 2- subtypes. The mobility of beta-receptors subjected to polyacrylamide gel electrophoresis was probed using antireceptor antibodies and nitrocellulose blots of the gels. Fat cell beta 1-adrenergic receptors display Mr = 67,000 under reducing conditions and Mr = 54,000 under nonreducing conditions, as previously reported (Moxham, C. P., and Malbon, C. C. (1985) Biochemistry 24, 6072-6077). Both beta 1- and beta 2-receptors displayed this same shift in electrophoretic mobility observed in the presence as compared to the absence of disulfide bridge-reducing agents, as detected both by autoradiography of the radiolabeled receptors and by immunoblotting of native receptors. Finally, isoelectric focusing of purified radioiodinated beta 1- and beta 2-adrenergic receptors revealed identical isoelectric points. These data are the first to provide analyses of immunological, structural, and biochemical features of beta 1- and beta 2-subtypes in tandem and underscore the structural similarities that exist between these pharmacologically distinct receptors.

Adipose Tissue↗
PubMed1989

Effect of viral infection of Fc receptors and immunologically nonspecific receptors of blood polymorphonuclear leukocytes: an in vitro model.

I describe the effect on phagocytic activity of the migration of bovine blood polymorphonuclear leukocytes (PMNL) through collagen and a monolayer of PK-15 cells in vitro infected with rotaviruses (strain OSU, RFC-17, SA-11), a picornavirus (strain SVDV), bovine herpesvirus (BHV-1) and equine herpesvirus (EHV-1). The PMNL were examined before and after their migration as follows: (1) for EA rosette formation with sensitized sheep erythrocytes, (2) for phagocytic activity mediated through Fc receptors (FcRs), (3) for phagocytic activity mediated through immunologically nonspecific receptors (INsRs). Random migration of PMNL through the infected monolayer to RPMI-1640 medium containing or lacking chemotactic agents (zymosan activated serum--Act. serum) and/or containing control agents (lipopolysaccharide--LPS or formyl-L-methionyl-L-leucyl-L-phenylalanine--fMLP) decreased the percentage of rosettes forming PMNL and the phagocytosis mediated by FcRs and INsRs. The results obtained suggest that the viruses used in this study independently of their biological properties exerted a suppressive action on the phagocytic activity mediated by FcRs and INsRs.

Cell Movement↗
PubMed1980

Immunological studies on human thymus. Occurrence and distribution of immunoglobulins and immunological receptors in myasthenia gravis and control patients.

Suspended cells and tissue sections from myasthenia gravis (MG) and control thymuses were characterized for surface expression and histological distribution of immunoglobulin (Ig) and receptors for sheep erythrocytes (SE), the Fc part of IgG (Fc gamma) and of IgM (Fc mu) and complement factors C3b and C3d (CR). In sections the cortical areas from both MG and control thymuses expressed SE as well as Fc gamma receptors, whereas medullary areas only showed weak SE binding. In contrast to control patients, MG thymuses also contained Ig+ cells confined to nodular areas of the thymic medulla. These nodules stained for both IgG and IgM, and were polyclonal with respect to light chains. In several cases IgD was found as well. In addition, the nodular areas were positive for C3b and C3d receptors. In serial sections, these Ig+ CR+ nodules corresponded to morphologically characteristic lymphoid follicles. Such B cell follicles were observed in variable numbers in all MG thymuses, whether hyperplastic or with normal histology. Five thymomas gave heterogeneous results with regard to immunological markers. Comparison of methods showed that receptor and Ig indication on sections was more sensitive than corresponding tests on thymus cells in suspension.

Adult↗
PubMed1987

Tumor growth modulation by a monoclonal antibody to the epidermal growth factor receptor: immunologically mediated and effector cell-independent effects.

A monoclonal antibody of IgG2a isotype (425) is described that reacts with the epidermal growth factor receptor on human cells of different tissue origins. Monoclonal antibody 425 mediates tumor cytotoxicity in vitro using mouse and human effector cells and suppresses in vivo tumor cell growth of epidermoid (A 431) and colorectal (SW 948) carcinoma-derived cell lines. The tumoricidal effects in vitro are proportional to the antigen density on target cells. At concentrations higher than 1 nM, monoclonal antibody 425 inhibits growth of epidermal growth factor receptor-bearing A 431 cells, showing an epidermal growth factor-like agonist activity on the growth properties of these cells. A 431 cultures grown in the presence of growth-inhibiting doses of antibody or epidermal growth factor reveal a clear decrease of the relative number of cells in S phase. Additionally, cells treated with the antibody show a decrease of G2-M-phase cells in some, but not all, cultures tested.

Animals↗
PubMed1982

[Ovarian cancer: markers, hormones receptors, immunological status].

Like other solid tumors ovarian tumors have been intensely investigated these past years to isolate specific tumoral antigens. These antigens are now used by clinical teams for post therapeutic follow-up. However, out of the 25 major antigens actually described in ovarian carcinomas, the only one that can be used today is the carcinoembryonic antigen (CEA). Moreover, an international collaborative work has demonstrated cross reacting antigenicity between these major tumoral antigens. Cellular enzymes (galactosyl transferase and sialyl-transferase) and hormonal receptors for proteinic hormones such as steroid hormones) are being studied but cannot be used as screening markers at this time.

Antigens, Neoplasm↗
PubMed1983

Is schizophrenia an immunologic receptor disorder?

A model is proposed for an autoimmune etiology for schizophrenia. We propose that schizophrenia is a syndrome (not a disease). We suggest that autoantibodies (and/or cell-mediated immunity) directed against autologous neurotransmitter receptors are responsible for the ebb and flow of psychotic symptomatology. The hypothesis is predicated on autoimmune models in other known receptor diseases as well as on the newly emerging recognition that general immune dysfunction exists in certain schizophreniform psychoses.

Antibody Formation↗
PubMed1988

Polymorphism of prolactin secreted by human prolactinoma cells: immunological, receptor binding, and biological properties of the glycosylated and nonglycosylated forms.

Multiple forms of PRL differing in their physicochemical and biological characteristics have been described. We have analyzed the molecular forms of human (h) PRL released in culture by pure hPRL-secreting tumors with a particular attention to glycosylated hPRL. The prolactinoma cells from six different tumors released, in serum-free conditions, 10-28 mg hPRL. The combination of polyacrylamide gel electrophoresis and immunoblotting techniques using a [125I]anti-hPRL monoclonal antibody allowed qualitative and quantitative analysis of the hPRL variants. The ratio of the glycosylated 25,000-mol wt form (G-hPRL) to the 23,000-mol wt nonglycosylated monomeric hPRL (NG-hPRL) varied from 0.13 to 0.25. Under the conditions of our studies, cleaved forms of the hormone (19,000 and 15,000 mol wt) accounted for less than 5% of the total immunoreactivity. G- and NG-hPRL were subsequently purified by gel filtration and lectin affinity chromatography. G-hPRL appeared fully sensitive to endoglycosidase F digestion, further supporting the presence of a freely accessible N-linked carbohydrate chain. When assayed for their ability to react with polyclonal antibodies directed against hPRL in a competitive RIA, G-hPRL was 3 times less immunoreactive than NG-hPRL. However, both types of hPRL exhibited superimposable displacement curves when tested in an immunoassay using an anti-hPRL monoclonal antibody. In binding studies using crude rabbit mammary gland membranes G-hPRL was half as potent as NG-hPRL. In stimulating the growth of the Nb2 lymphoma cell line, G-hPRL was 50% less active than NG-hPRL. Thus 1) under basal conditions, hPRL undergoes partial and variable glycosylation; 2) glycosylation of the hormone may modulate its immunoreactivity; 3) glycosylation of hPRL not only lowers its mammary gland receptor binding capacity but also its growth-promoting activity.

Adenoma↗
PubMed1987

Structural studies of T200 glycoprotein and the IL-2 receptor.

Immunological analysis of the cell surface of hematopoietic cells has led to the identification of many different cell membrane molecules, some of which have well-defined functions as receptors. In general, however, the role of most lymphocyte cell surface molecules remains ill-defined even in cases in which antibody inhibition studies have given some insight into the biological processes in which they participate. Here we describe molecular and biochemical studies of T200 glycoprotein (leukocyte-common antigen) and the IL-2 receptor which illustrate the kinds of approaches that can be currently used to characterize individual molecules. T200 glycoprotein is a large Mr glycoprotein found exclusively on leukocytes. However, the exact Mr varies in a cell-type-specific fashion and this property is conserved between different species. Comparison of the rat, mouse and human cDNA sequences show that the large cytoplasmic portion of the molecule is well-conserved, approximately 90%, whereas the exterior portion is only about 50% homologous. Cell-type-specific differences in the primary sequence of the molecule have been identified in the N-terminal portion of the molecules. In contrast to T200, the function of the IL-2 receptor is well-known. The interaction of IL-2 with its receptor provides a growth signal that determines the magnitude and duration of T-cell responses. Limited proteolysis studies provide the first direct biochemical evidence that the external region of the IL-2 receptor consists of two independent domains. 125I-labeled IL-2 has been chemically crosslinked to the receptor and proteolytic cleavage of the crosslinked product indicates that IL-2 is selectively bound to the N-terminal domain of the receptor.

Animals↗
PubMed1992

Trypanosoma brucei brucei: antigenic stability of its LDL receptor and immunological cross-reactivity with the LDL receptor of the mammalian host.

The rapid growth of Trypanosoma brucei brucei in the blood and tissue fluids of vertebrates requires the receptor-mediated endocytosis of LDL from the host (Coppens et al. 1987; Gillett and Owen 1987) and is slowed by a monospecific rabbit antiserum against the purified LDL receptor of the parasite. We have used this antiserum in combination with several well-characterized antigenic variants (originating from stock 427: MITat 1.1a, 1.3a, 1.4a, 1.5a, 1.5d, 1.8b) to examine whether the LDL receptor of T. b. brucei is a stable surface antigen, common to all parasite variants despite antigenic variation of the major surface glycoprotein, and whether it is immunologically distinct from the LDL receptor of the host. At low concentrations, binding at 4 degrees C of rat LDL to several variants of T. b. brucei and to isolated rat hepatocytes was inhibited to a similar extent by the antiserum. In double immunodiffusion, a single precipitation line was observed, showing continuity between the extracts of all variants as well as between that of trypanosomes and of mammalian tissues. In Western blots of trypanosome extracts, the LDL receptor was strongly labeled as a single band of Mr 145,000, whereas with a rat liver extract, a single band of similar electrophoretic mobility was weakly labeled at a high concentration of the antiserum. In conclusion, the LDL receptor occurred in all variants of T. b. brucei, was a stable surface antigen despite variation of the major surface glycoprotein, and displayed biochemical and immunological similarities with the LDL receptor of the rat host.

Animals↗
PubMed1994

Rodent insulin receptors are immunologically different from other mammalian insulin receptors.

Four monoclonal antibodies (MA-5, MA-10, MA-20, and MA-51) and one polyclonal antibody (ARS-2) against human insulin receptor were used to immunoprecipitate the insulin receptor from several species which had been photolabeled with N epsilon B29-monoazido-benzoyl-[125I]iodoinsulin. All four monoclonal antibodies immunoprecipitated human insulin receptor from human placental membranes. MA-10 and MA-51, but not MA-5 or MA-20, immunoprecipitated insulin receptors from liver plasma membranes of rabbit, guinea pig, dog, cattle, pig, and chicken. None of the monoclonal antibodies immunoprecipitated insulin receptors of rat, mouse, hamster, or chinchilla. In contrast, all of the insulin receptors were immunoprecipitated by the polyclonal anti-insulin receptor antibody, ARS-2. MA-10 and MA-51 compared with [125I]iodoinsulin for binding to guinea pig and rabbit liver plasma membranes in a fashion similar to insulin, although less effectively. MA-51 also mimicked the action of insulin by stimulating lipogenesis and autophosphorylation of the insulin receptor beta subunit in isolated rabbit adipocytes. The results suggest that insulin receptors of mammals, other than rodent, share with human insulin receptor the same epitope(s) recognized by MA-10 and MA-51. Rodent insulin receptors, with the exception of guinea pig, are different. We speculate that the difference lies in the amino acid sequence 485-599 of the alpha subunit of the insulin receptor.

Adipose Tissue↗