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PubMed1995

Lack of cross-reactivity of lytic antibodies with bloodstream forms of Trypanosoma cruzi zymodemes generated in a mouse experimental model.

Immune sera from mice infected with specific Zymodemes of Trypanosoma cruzi parasites displayed preferential in vitro complement-mediated trypanolytic activity with homologous or genetically related bloodstream trypomastigotes. Culture-derived and metacyclic trypomastigotes were more susceptible to lytic antibodies than bloodstream trypomastigote forms when the same serum panel was tested. Different levels of maximal trypanolytic reaction were observed when several parasites and sera were tested, suggesting that T. cruzi stocks are dissimilar in their efficiency to evade the lytic reaction, probably by capping and shedding mechanisms. A discussion based on the heterogeneity of surface antigens able to elicit the lytic response among different T. cruzi populations is presented.

Animals↗
PubMed2001

LAP, a lymphocyte activation gene-3 (LAG-3)-associated protein that binds to a repeated EP motif in the intracellular region of LAG-3, may participate in the down-regulation of the CD3/TCR activation pathway.

The threshold, extent and termination of TCR activation is controlled in part by inhibitory co-receptors expressed on activated T cells. The lymphocyte activation gene product (LAG-3), a ligand for MHC class II molecules co-caps with the CD3/TCR complex and inhibits cell proliferation and cytokine secretion in response to CD3 signaling. We first investigated whether LAG-3 is localized in activated T cells in detergent-resistant membrane rafts enriched in glycosphingolipids and cholesterol. We showed that both LAG-3 and MHC class II are present in the cell fraction of glycosphingolipid-rich complexes (GSL complexes) before the assembly of the immunological synapse by CD3/TCR complex cross-linking. Using the LAG-3 intracytoplasmic region as bait in the yeast two-hybrid cloning system, we next identified a novel protein termed LAP for LAG-3-associated protein. LAP is encoded by a 1.8-kb RNA message in lymphocytes and encodes a 45-kDa protein that is expressed in most tissues. We showed that LAP binds specifically in vitro and in vivo to the Glu-Pro (EP) repeated motif present in the LAG-3 intracytoplasmic region. LAP also binds to the EP motif of another functionally important receptor, the PDGFR. Thus, LAP is a candidate molecule for a new type of signal transduction and/or coupling of clustered rafts to the microtubule networks that could explain how negative signaling of co-receptors may occur through molecules devoid of any immunoreceptor tyrosine-based inhibitory motif consensus sequence.

Amino Acid Motifs↗
PubMed1982

Immunoserological, immunohistochemical and immunobiological studies on an antigenic glycoprotein isolated from human seminal plasma.

The seminal plasma and a fraction of the spermatozoal membrane solubilised by sarkosyl contain similar antigenic determinants. The glycoprotein isolated from the seminal plasma also contains determinants which are immunologically identical to those of the sarkosyl soluble fraction. Three of these determinants were identified as: two oligosaccharide chains with terminal N-acetyl neuraminic acid and with subterminal alpha-L-fucopyranose and beta-D-galactopyranose residues respectively, and an oligosaccharide chain with beta-D-galactopyranose as non-reducing end-chain. The receptors on the spermatozoa to anti-glycoprotein and anti-seminal plasma antibodies are localized. The specificity of the receptors localised in the neck region depends entirely on the presence of N-acetyl neuraminic acid as end-chain group while the specificity of the receptors to the anti-seminal plasma antibodies in the intermediate segment plus tail and to the anti-glycoprotein antibodies in the post-nuclear cap depends also on the subterminal units. At least two other receptors in the equatorial zone are ended by residues different from the N-acetyl neuraminic acid. One of them, which is also found in the acrosome, does not have specificity for anti-glycoprotein antibodies, while the other, which is not in the acrosome, has anti-glycoprotein antibodies specificity and may have a terminal beta-D-galactopyranose residue.

Antigens↗
PubMed1997

(Carboxyalkyl)pyrroles in human plasma and oxidized low-density lipoproteins.

Free-radical oxidation of human plasma low-density lipoprotein (LDL) produces (carboxyalkyl)pyrrole (CAP) epitopes that were detected with enzyme-linked immunosorbent assays using antibodies raised against keyhole limpet hemocyanin (KLH)-bound 2-(omega-carboxyheptyl)-pyrrole (CHP) and 2-(omega-carboxypropyl)pyrrole (CPP). These antibodies exhibit high structural selectivity (< 0.5% cross-reactivity) in competitive binding inhibition assays with the corresponding human serum albumin (HSA)-bound pyrroles. No cross-reactivity was detected for HSA-bound 2-pentylpyrrole, an epitope that is generated by a reaction of 4-hydroxy-2-nonenal (HNE) with protein lysyl residues. Oxidation of either arachidonic or linoleic acid in the presence of HSA produced an HNE-derived 2-pentylpyrrole epitope. However, only oxidation of linoleic acid formed HSA-bound CHP, while only oxidation of arachidonic acid generated HSA-bound CPP. Since ester hydrolysis with KOH markedly elevated levels of immunoreactive epitopes detected in oxidized LDL, the CAPs are presumably generated by reactions of oxidized cholesteryl esters, triglycerides, and phospholipids with LDL protein, and only some of these oxidized esters are hydrolyzed, e.g., by phospholipase activity associated with LDL. Protein-bound CHP immunoreactivity was detected in human plasma, and levels are significantly elevated in renal failure and atherosclerosis patients compared with healthy volunteers. This provides the first evidence for the biological occurrence of protein-bound CAPs in vivo and further suggests that free-radical oxidation of polyunsaturated lipids produces hydroxyalkenal carboxylate esters whose gamma-hydroxy-alpha,beta-unsaturated aldehyde functionality and reactivity resemble that of HNE.

Adjuvants, Immunologic↗
PubMed1979

Primary in vitro immunogenicity of liposomal model membranes in mouse spleen cell cultures.

Neither 2,4-dinitrophenyl-6-N-aminocaproylphosphatidylethanolamine (DNP-Cap-PE) nor fluoresceinthiocarbamylphosphatidylethanolamine (F1-PE) induces hapten-specific plaque-forming cells (PFC) when incubated with suspensions of spleen cells from unimmunized C57BL/6J mice. However, PFC are produced after incorporation of these synthetic lipid antigens into liposomal model membranes. The in vitro response is characterized by the following: a) it is time and dose dependent; b) the frequency of IgM PFC exceeds IgG PFC; c) both nonadherent and adherent cells are required (2-mercaptoethanol can replace the requirement for adherent cells in some experiments); d) depletion of thymus-derived cells by treatment with anti-theta antiserum plus complement does not diminish the response; e) spleen cells from nude BALB/c mice also produce PFC. Thus, the essential features of the in vivo immunogenicity of DNP-Cap-PE and F1-PE sensitized liposomes, which have been previously described, can be replicated in an in vitro cell culture system.

Aminocaproates↗
PubMed1997

The BASP1 family of myristoylated proteins abundant in axonal termini. Primary structure analysis and physico-chemical properties.

Proteins BASP1 and GAP-43/B-50, which are abundant in nerve endings, show a number of similar physico-chemical properties. Nevertheless, they belong to different protein families. In this work, complete amino acid sequences of bovine BASP1 and human BASP1 were established. They proved to be very similar to the sequences of rat brain protein NAP-22 and chicken brain protein CAP-23. Relatively to human BASP1 its bovine, rat and chicken analogues show 80%, 70% and 45% sequence identity respectively, confirming their membership of a definite protein family (BASP1 family). All members of BASP1 family contain several 'good' PEST sequences characteristic for short-living proteins. Conservation of PEST sequences in BASP1 of different species points to their significance for BASP1 functions. In contrast to GAP-43/B-50 showing high immunological cross-reactivity between the proteins belonging to different species of mammals, immunological properties of BASP1 are species specific. BASP1 shows both high hydrophilicity and some properties characteristic for hydrophobic proteins. These properties are caused by N-terminal myristoylation of BASP1 molecules. Unlike GAP-43/B-50, BASP1 is present in high amounts also in some non-nervous tissues: testis, kidney and lymphoid organs (spleen, thymus). So far examined characteristics, including myristoylation, peptide maps and detected by isoelectrofocusing microheterogeneity, proved to be the same for BASP1 samples isolated from both brain and non-nervous tissues. Therefore, in spite of different physiological consequences, biochemical functions of BASP1 must also be similar in different tissues.

Amino Acid Sequence↗
PubMed1991

Clinical evaluation of a new in-vitro assay for specific IgE, the immuno CAP system.

The Pharmacia CAP system is a new assay for specific IgE characterized by a new solid phase (hydrophilic polymer encased in a capsule). The CAP results were compared to those of the Phadebas IgE RAST and skin-prick tests (SPT) performed in 145 subjects suffering from rhinitis and/or asthma with eight common inhalant allergens (total number of tests = 1160). Concording CAP/RAST results were found in 91% of the tests. The CAP was positive in 78% and the RAST in 65% of the positive SPT. Conversely, the CAP was negative in 90.6% and the RAST in 96.4% of the negative SPT. A pattern negative SPT, negative RAST and positive CAP' was found in 56 tests (40 subjects): in four such subjects, the CAP positivity was confirmed by a positive IgE crossed radioimmunoelectrophoresis. Three borderline positive results were found among 240 negative controls (serum from cord blood or non-atopics). These data indicate that compared with SPT the CAP system is (a) more sensitive than the Pharmacia RAST and (b) does not seem less specific.

Adolescent↗
PubMed1985

The effect of cimetidine on natural killer activity of peripheral blood lymphocytes of patients with ovarian carcinoma.

The effect of cimetidine on the natural killer (NK) activity of peripheral blood lymphocytes (PBL) of 32 patients with ovarian carcinoma was studied before and after surgery or chemotherapy. There was no significant difference in the NK activity between normal healthy women and patients who had been disease-free for more than a year after initial surgery, while those in patients with a large residual tumor after surgery were profoundly suppressed. Cimetidine stimulated the NK activity in the disease-free patients in vivo or in vitro. In addition, cimetidine augmented the response to phytohemagglutinin of PBL from the disease-free patients. The NK activity of PBL of patients with a large residual tumor under chemotherapy consisting of cisplatinum, adriamycin and cyclophosphamide, "CAP," was about half of that before initiation of chemotherapy. The inhibition of the NK activity by chemotherapy was abrogated by in vitro exposure of the PBL to cimetidine.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Interaction of the human autoantigen p150 with splicing snRNPs.

An important goal of studies on pre-mRNA splicing is to identify factors that mediate the snRNP-snRNP and snRNP-pre-mRNA interactions that take place in the spliceosome. The U4/U6 snRNP is one of the four snRNPs that are subunits of spliceosomes. A rare patient autoimmune serum (MaS serum) has recently been identified that specifically immunoprecipitates U4/U6 snRNP from HeLa cell extracts through recognition of a 150 kDa autoantigen (p150) (Okano and Medsger, Journal of Immunology, 146, 535-542, 1991). Here we show that in addition to U4/U6 snRNP, p150 can also be detected associated with 20 S U5, U4/U6.U5 and 17 S U2 snRNPs, but not with U1 snRNP. In each particle p150 is present in sub-stoichiometric levels relative to the major snRNP proteins. We show that MaS serum selectively immunoprecipitates a sub-population of U4/U6 snRNPs in which the m3G-cap structure is masked and that p150 is preferentially associated with U6 snRNA in the U4/U6 particle. Anti-p150 antibodies show widespread nucleoplasmic staining, excluding nucleoli, with an elevated concentration in coiled bodies. This changes to a discrete punctate pattern when cells are treated with alpha-amanitin. Both the cytological and biochemical data indicate that the p150 autoantigen is a snRNP-associated factor in vivo. We also present biochemical evidence confirming that assembly of U4/U6 and U5 snRNPs into a U4/U6.U5 tri-snRNP particle is an integral step in the spliceosome assembly pathway. Addition of the purified U4/U6.U5 tri-snRNP restores splicing activity to inactivated HeLa nuclear extracts in which splicing had been inhibited by specific depletion of either the U4/U6 or U5 snRNPs.

Autoantibodies↗
PubMed2000

Chronic infection and coronary artery disease.

On a variety of fronts, chronic infection has been found to be significantly associated with the development of atherosclerosis and the clinical complications of unstable angina, myocardial infarction, and stroke. For the most part, these are still just associations. Specific causative relationships on par with that determined between H. pylori and peptic ulcer disease have not yet been established. Potential mechanisms whereby chronic infections may play a role in atherogenesis are myriad. In the case of C. pneumoniae, the effect may result from direct vessel wall colonization, which may damage the vessel directly or indirectly by initiating immunologic responses. In other cases, the effect may simply be that of enhancing the preexisting chronic inflammatory response of the body to standard risk factors, such as hyperlipidemia. Even though the infectious agent may not directly infect the vessel wall, it may perform its critical role from afar. Chronic infection might also influence preexisting plaque by enhancing T cell activation or other inflammatory responses that may participate in the destabilization of the intimal cap. Chronic infection may play a role in the initiation, progression, or destabilization of atherosclerotic plaques. The infectious agents with the most evidence to support a causative role in atherosclerosis include C. pneumoniae and cytomegalovirus. Evidence is mounting for a variety of other potential agents, including H. pylori, various periodontal agents, and even hepatitis A. Future studies are expected to elucidate further the pathophysiologic relationship between chronic infection and atherosclerosis and to evaluate the potential of a variety of treatment approaches, including antibiotics.

Animals↗
PubMed1975

The effects of glycosaminoglycans on surface-mediated interactions of lymphoid cells.

The effect of chondroitin sulphate (CS) was studied in two cell surface-mediated interactions, the complement-independent contact reaction and antibody-induced capping of H-2 antigens. CS inhibited contact cytotoxicity when present in the reaction medium, but preincubation in CS of either killer cells or target cells had no effect. The capacity of CS-pretreated target cells to absorb H-2 antibodies was not reduced. However, a similar pretreatment resulted in an increased readiness to capping as induced by H-2 antibody followed by an anti-mouse immunoglobulin; in control cells time taken for the same percentage of caps to be formed was considerably longer than in CS-pretreated cells. A possible mechanism of this CS effect and the general biological role of glycosaminoglycans (particularly in immune interactions) is discussed.

Animals↗
PubMed1997

[A novel diagnostic method for allergy "LUCICA HRT"].

We developed a novel glass microfiber-based histamine release test (HRT) which is characteristic of response of basophil leukocyte to allergens in vitro. It allows the determination of 20 allergens (10 for inhalation allergy, and the other for food allergy) at the same time using a small amount of whole blood. For 158 patients of inhalation allergy and 135 patients of food allergy, they were evaluated by HRT, CAP-RAST, skin test, and provocation test. The concordance of HRT, CAP-RAST, and skin test were 78%, 72%, and 62% in inhalation allergy, and 84%, 71%, and 81% in food allergy, respectively. The specificity of HRT, CAP-RAST, and skin test were 63%, 37%, and 19% in inhalation allergy, and 92%, 63%, and 83% in food allergy, respectively. The positive predictive value of HRT, CAP-RAST, and skin test were 79%, 71%, and 63%, respectively. The false positive ratio of HRT (14%) was lower than that of CAP-RAST (42%). The sensitivity of CAP-RAST was higher than that of HRT. In addition, we experienced a case of patient who showed significant improvement by treatment. At initial stage, not only the symptoms were erythema and scratching but also HRT, CAP-RAST, and skin test resulted in positive. Four months later, he had no allergic symptoms, HRT resulted in negative, but CAP-RAST and skin test resulted in still positive. From these results, we concluded that CAP-RAST is good for screening of etiological allergens and that HRT is a useful diagnostic method for the confirmation of a clinical allergy.

Adolescent↗
PubMed2005

Characterization of Striped jack nervous necrosis virus subgenomic RNA3 and biological activities of its encoded protein B2.

Striped jack nervous necrosis virus (SJNNV), which infects fish, is the type species of the genus Betanodavirus. This virus has a bipartite genome of positive-strand RNAs, designated RNAs 1 and 2. A small RNA (ca. 0.4 kb) has been detected from SJNNV-infected cells, which was newly synthesized and corresponded to the 3'-terminal region of RNA1. Rapid amplification of cDNA ends analysis showed that the 5' end of this small RNA (designated RNA3) initiated at nt 2730 of the corresponding RNA1 sequence and contained a 5' cap structure. Substitution of the first nucleotide of the subgenomic RNA sequence within RNA1 selectively inhibited production of the positive-strand RNA3 but not of the negative-strand RNA3, which suggests that RNA3 may be synthesized via a premature termination model. The single RNA3-encoded protein (designated protein B2) was expressed in Escherichia coli, purified and used to immunize a rabbit to obtain an anti-protein B2 polyclonal antibody. An immunological test showed that the antigen was specifically detected in the central nervous system and retina of infected striped jack larvae (Pseudocaranx dentex), and in the cytoplasm of infected cultured E-11 cells. These results indicate that SJNNV produces subgenomic RNA3 from RNA1 and synthesizes protein B2 during virus multiplication, as reported for alphanodaviruses. In addition, an Agrobacterium co-infiltration assay established in transgenic plants that express green fluorescent protein showed that SJNNV protein B2 has a potent RNA silencing-suppression activity, as discovered for the protein B2 of insect-infecting alphanodaviruses.

Animals↗
PubMed1976

Mechanism of injury of virus-infected cells by antiviral antibody and complement: participation of IgG, F(ab')2, and the alternative complement pathway.

Antibody-mediated C-dependent lysis of cell lines infected with herpes simplex type 1 virus, influenza A degrees virus, measles virus, and mumps virus occurred by the alternative C pathway with the participation of IgG antibodies. Lysis occurred only with immune human sera, Mg++ EGTA immune sera, and immune sera depleted of C4 or treated with Fab anti-C4. Lysis did not occur with nonimmune sera, Mg++ EDTA immune sera, and immune sera heated 50 degrees C for 25 min, depleted of factor B or treated with Fab antifactor B. Lysis was restored to heated and factor B immunodepleted immune sera by addition of factor B, but not by addition of an excess of C2. Further studies showed that lysis of HeLa cells infected with measles virus was induced by both immune IgG and F(ab')2 but not Fab' in the presence of a nonantibody-containing human C source. Lysis of measles virus-infected cells was also indpendent of movement of viral antigens on the surface of the infected cells, as inhibition of viral antigen capping by cytochalasin B or sodium azide was not associated with abrogation of immune lysis.

Antibodies, Viral↗
PubMedDate not supplied

Comparison of multiple-antigen simultaneous test and CAP systems for diagnosis of nasal allergy.

The multiple-antigen simultaneous test (MAST) is a simple system that uses no radioactive agents and allows simultaneous examination of multiple antigens. CAP is a quick new, in vitro system that is more sensitive than the radio-allergosorbent test (RAST). To evaluate their clinical efficacies, we examined the correlation between the MAST and CAP systems. Serum samples were collected from 33 patients with nasal allergies, 13 males and 20 females, mean age 31.1 years. The MAST and CAP were used for 7 inhaled allergens: house dust, Dermatophagoides farinae, Japanese cedar, timothy, sweet vernal grass, ragweed and mugwort. The correlation coefficients found for MAST and CAP were significant for all the allergens tested. In addition, high values for sensitivity, specificity and efficiency were obtained for all the allergens. The MAST system provided the same information as the CAP system. Although CAP tended to have better sensitivity, some of its positive results may clinically be false-positive. We believe that the MAST and CAP are both useful for the detection of allergens but that the diagnosis of allergy must be based on results of detailed examinations such as use of the skin test, the nasal provocation test and clinical symptoms.

Adolescent↗
PubMed1991

[The Norwegian Antarctic expedition 1989-1990--medical contingency, work and research].

Antarctica is the world's coldest, driest, highest and most windy continent. The ice may reach a thickness of nearly five km, and the greater part of the world's fresh water is bound in this ice cap. The lowest temperature ever measured is -90 degrees C. The weather during this summer expedition was pleasant, and the temperature seldom fell below -30 degrees C. The 35 persons in the land party included two physicians and one nurse. No serious injury or disease occurred. The participants seemed experience an increase in lean body weight and loss of fat during five weeks in tents. Extensive data were collected for medical-psychological projects on immunology, adaptation to cold, exhaustion from cold and stress. Some results have been published in separate reports.

Adaptation, Physiological↗
PubMed1979

The mechanism of rosette formation between sheep red blood cells and L-A9 fibroblasts.

More than 20% of mouse L-A9 fibroblasts from rosettes with sheep red blood cells. This relatively weak interaction is mediated by receptors of glycoprotein nature; species-specific antigens of SRBC are part of, or lie in close proximity to, this binding. SRBC receptors are present on most L-A9 fibroblasts, neither Con A receptors nor MHL products are part of the SRBC receptors. However, Con A- and H-2 antibody-induced alterations in the membrane and cytoskeletal system accompanying cap formation produce a strong inhibition of rosette formation. This inhibition may be due to an interference into the adhesion by involving the cytoskeletal system in the redistribution processes because the same effect was obtained with Colcemid and cytochalasin B.

Animals↗
PubMed2001

Tomato allergy in children and young adults: cross-reactivity with latex and potato.

BACKGROUND: Several studies have shown that allergy to natural rubber latex is associated with cross-reactivity to certain foods such as tomato and potato. The objective was to investigate the clinical and immunologic differences between a group of patients with clinical allergy to tomato and latex and another which had only clinical allergy to tomato. We also aimed to assess, in vitro, the relationship of tomato and latex allergens, which could explain the cross-reactivity. METHODS: Forty patients with histories of adverse reactions to tomato and IgE-mediated hypersensitivity were enrolled in the study. Tomato, latex, and potato components were analyzed by SDS-PAGE immunoblotting. CAP and immunoblot inhibition were used to study allergen cross-reactivity. RESULTS: Patients from group A had a mean age of 13.2 years, and in group B the mean age was 21.7 years. In group B, 9/10 patients belonged to the latex-fruits syndrome. All patients of both groups tolerated potato. Immunoblotting patterns obtained with patients' sera from pool A showed IgE-binding bands to tomato ranging from 44 to 46 kDa and a triple band at 67 kDa. For latex, there was a strong binding at 44 kDa, and potato showed a strong band of 44 kDa and a 67-kDa triple band. In pool B, the binding to the band of 44 kDa in latex and tomato was more intense than in pool A. In pool A, immunoblot inhibition with potato allergen showed an intense inhibition of the three allergens (potato, latex, and tomato); with latex, inhibition was partial and with tomato, a complete inhibition of tomato and latex was observed, and a partial inhibition of potato. In pool B, the inhibition pattern followed a similar tendency to pool A. The CAP inhibition confirmed the high rate of cross-reactivity between tomato, potato, and latex. CONCLUSIONS: In our study, tomato, potato, and latex showed a common band of 44-46 kDa probably corresponding to patatin. This protein could be implicated in the high cross-reactivity between tomato, latex, and potato observed in the immunoblot and CAP inhibition.

Adolescent↗