Immunological fingerprint of 4CMenB recombinant antigens via protein microarray reveals key immunosignatures correlating with bactericidal activity.

Serogroup B meningococcus (MenB) is a leading cause of meningitis and sepsis across the world and vaccination is the most effective way to protect against this disease. 4CMenB is a multi-component vaccine against MenB, which is now licensed for use in subjects >2 months of age in several countries. In this study, we describe the development and use of an ad hoc protein microarray to study the immune response induced by the three major 4CMenB antigenic components (fHbp, NHBA and NadA) in individual sera from vaccinated infants, adolescents and adults. The resulting 4CMenB protein antigen fingerprinting allowed the identification of specific human antibody repertoire correlating with the bactericidal response elicited in each subject. This work represents an example of epitope mapping of the immune response induced by a multicomponent vaccine in different age groups with the identification of protective signatures. It shows the high flexibility of this microarray based methodology in terms of high-throughput information and minimal volume of biological samples needed.

Progress in the development of ß-lactams as N-Acylethanolamine Acid Amidase (NAAA) inhibitors: Synthesis and SAR study of new, potent N-O-substituted derivatives.

The anti-inflammatory effects resulting from raising the levels of palmitoylethanolamide (PEA), an endogenous bioactive lipid, led to envisage N-Acylethanolamine Acid Amidase (NAAA), the cysteine hydrolase mainly responsible for PEA degradation, as an attractive target for small molecule inhibitors. Previous work in our group identified serine-derived ß-lactams as potent and systemically active inhibitors of NAAA activity. Aiming to expand the SAR study around this class of compounds, we investigated the effect of the substitution on the endocyclic nitrogen by designing and synthesizing a series of N-substituted ß-lactams. The present work describes the synthesis of new N-O-alkyl and N-O-aryl substituted ß-lactams and reports the results of the structure activity relationship (SAR) study leading to the discovery of a novel, single-digit nanomolar NAAA inhibitor (37). Compound 37 was shown in vitro to inhibit human NAAA via S-acylation of the catalytic cysteine, and to display very good selectivity vs. human Acid Ceramidase, a cysteine amidase structurally related to NAAA. Preliminary in vivo studies showed that compound 37, administered topically, reduced paw edema and heat hyperalgesia in a carrageenan-induced inflammation mouse model. The high in vitro potency of 37 as NAAA inhibitor, and its encouraging in vivo activity qualify this compound as a new tool for the study of the role of NAAA in inflammatory and pain states.

Rationally designed strings of promiscuous CD4(+) T cell epitopes provide help to Haemophilus influenzae type b oligosaccharide: a model for new conjugate vaccines.

The age-related and T cell-independent immunological properties of most capsular polysaccharides limit their use as vaccines, especially in children under 2 years of age. To overcome these limitations, polysaccharide antigens have been successfully conjugated to a variety of carrier proteins, such as diphtheria toxoid or tetanus toxoid (TT) and the diphtheria mutant (CRM197) to produce very successful glycoconjugate vaccines. The increasing demand for new conjugate vaccines requires the availability of additional carriers providing high and long-lasting T helper cell immunity. Here we describe the design and construction of three recombinant carrier proteins (N6, N10, N19) constituted by strings of 6, 10 or 19 human CD4(+) T cell epitopes from various pathogen-derived antigens, including TT and proteins from Plasmodium falciparum, influenza virus and hepatitis B virus. Each of these epitopes is defined as universal in that it binds to many human MHC class II molecules. When conjugated to Haemophilus influenzae type b (Hib) oligosaccharide, these carriers elicit a potent anti-Hib antibody response in mice. In the case of the N19-Hib conjugate, this response is at least as good as that observed with CRM197-Hib, a conjugate vaccine currently used for mass immunization. We also show that some of the universal epitopes constituting the recombinant carriers are specifically recognized by two human in vitro systems, suggesting that T cell memory is provided by the selected epitopes. The data indicate that rationally designed recombinant polyepitope proteins represent excellent candidates for the development and clinical testing of new conjugate vaccines.

CD81 extracellular domain 3D structure: insight into the tetraspanin superfamily structural motifs.

Human CD81, a known receptor for hepatitis C virus envelope E2 glycoprotein, is a transmembrane protein belonging to the tetraspanin family. The crystal structure of human CD81 large extracellular domain is reported here at 1.6 A resolution. Each subunit within the homodimeric protein displays a mushroom-like structure, composed of five alpha-helices arranged in 'stalk' and 'head' subdomains. Residues known to be involved in virus binding can be mapped onto the head subdomain, providing a basis for the design of antiviral drugs and vaccines. Sequence analysis of 160 tetraspanins indicates that key structural features and the new protein fold observed in the CD81 large extracellular domain are conserved within the family. On these bases, it is proposed that tetraspanins may assemble at the cell surface into homo- and/or hetero-dimers through a conserved hydrophobic interface located in the stalk subdomain, while interacting with other liganding proteins, including hepatitis C virus E2, through the head subdomain. The topology of such interactions provides a rationale for the assembly of the so-called tetraspan-web.

Crystallization and preliminary crystallographic studies on the large extracellular domain of human CD81, a tetraspanin receptor for hepatitis C virus.

The large extracellular domain of CD81, a member of the tetraspanin family and a receptor protein for hepatitis C virus envelope E2 glycoprotein, has been expressed, purified and subsequently crystallized using the sitting-drop vapour-diffusion technique. Native diffraction data to 1.6 A resolution were obtained at the ID14 beamline of the European Synchrotron Radiation Facility from a flash-frozen crystal at 100 K. The crystals belong to space group P2(1), with unit-cell parameters a = 31.5, b = 77.2, c = 38.5 A, beta = 107.4 degrees, and are likely to contain two extracellular domains (2 x 99 residues) per asymmetric unit.

Structure-function analysis of hepatitis C virus envelope-CD81 binding.

Hepatitis C virus (HCV) is a major human pathogen causing chronic liver disease. We have recently found that the large extracellular loop (LEL) of human CD81 binds HCV. This finding prompted us to assess the structure-function features of HCV-CD81 interaction by using recombinant E2 protein and a recombinant soluble form of CD81 LEL. We have found that HCV-E2 binds CD81 LEL with a K(d) of 1.8 nM; CD81 can mediate attachment of E2 on hepatocytes; engagement of CD81 mediates internalization of only 30% of CD81 molecules even after 12 h; and the four cysteines of CD81 LEL form two disulfide bridges, the integrity of which is necessary for CD81-HCV interaction. Altogether our data suggest that neutralizing antibodies aimed at interfering with HCV binding to human cells should have an affinity higher than 10(-9) M, that HCV binding to hepatocytes may not entirely depend on CD81, that CD81 is an attachment receptor with poor capacity to mediate virus entry, and that reducing environments do not favor CD81-HCV interaction. These studies provide a better understanding of the CD81-HCV interaction and should thus help to elucidate the viral life cycle and to develop new strategies aimed at interfering with HCV binding to human cells.

[Patency study of internal mammary artery grafts: the usefulness of echo-enhancers for identifying the flow signal by color Doppler echocardiography]. / Estudio de la permeabilidad de los injertos de arteria mamaria interna: utilidad de los ecopotenciadores para identificar la señal de flujo mediante ecocardiografía-Doppler color.

OBJECTIVES: a) To study the capacity of the technique of high-frequency color Doppler to detect flow signal of left internal mammary artery grafts; b) to assess the usefulness of an echo-enhancer agent to facilitate the detection of the signal, and c) to evaluate the patency of the graft according to its pulsed Doppler velocity profile pattern. METHODS: 39 consecutive patients were studied. A Hewlett-Packard 5500 echocardiograph was used, with a high-frequency probe (S12) applied at the high left parasternal border. When a graft signal was not elicited after a predetermined 5-minute check period, an intravenous dose of 4 g of Levovist (Schering España) at 400 mg/ml was administrated. According to previous studies, a pulsed Doppler flow profile with a predominantly diastolic pattern was considered a normal graft patency, while a systolic one was deemed as abnormal. RESULTS: Graft flow was identified by color Doppler in 33/39 patients (85%). The additional use of an echo-enhancer in 6 patients with no detected signal increased this proportion to 38/39 (97%). Normal flow patterns were seen in 34/38 (89%). Among the four patients with abnormal pattern, 1 case of early myocardial infarction was observed, while angiographic studies showed distal occlusion of the graft in 1 or the presence of competitive flow in 2 patients. CONCLUSIONS: The high-frequency color Doppler technique allows the detection of a flow signal from internal mammary artery grafts in most patients. The administration of an echo-enhancer agent is useful in those with non detectable signals. An abnormal pulsed Doppler velocity pattern indicates graft malfunction.

The comparison of the effect of LTR72 and MF59 adjuvants on mouse humoral response to intranasal immunisation with human papillomavirus type 6b (HPV-6b) virus-like particles.

Infections with genital human papillomaviruses (HPV) are likely to be neutralised more efficiently if a mucosal immune response can be elicited at the viral entry site. Local IgA antibodies are highly induced when antigens are co-administered with mucosal adjuvants, such as cholera toxin (CT) and Escherichia coli heat labile enterotoxin (LT) which, however, are not expected to have wide application because of their pronounced toxicity. We have immunised mice intranasally with HPV-6b virus-like particles (VLPs) and a genetically modified LT-derived molecule with only residual toxicity, LTR72, and compared the humoral responses with those obtained following systemic immunisation with VLPs and the MF59 adjuvant. Titration of anti-HPV antibodies in sera and vaginal secretions established that LTR72 was able to elicit higher serum and mucosal IgA titers, in addition to IgG serum levels, comparable to those obtained by parenteral immunisation. These results confirm the potential of toxin-derived adjuvants and extend their use in combination with HPV antigens.

Influence of single base change in Shine-Dalgarno sequence on the stability of B. subtilis plasmid PSM604.

B. Subtilis expression plasmids generally require a stringent Shine-Dalgarno Sequence (SDS). Site-directed-mutagenesis was explored to change the Shine-Dalgarno Sequence from AAAAATGGGG (mutant type) to AAAAAGGGGG (wild type) in recombinant plasmid PSM604. The single base substitution made the plasmid with wild SDS unstable in structure and segregation. The interaction of SDS with subtilisin leader sequence of PSM604 might be responsible for the instability of plasmid.

Secretory expression of recombinant diphtheria toxin mutants in B. Subtilis.

Three diphtheria toxin (DT) mutants CRM-197, DT-del (148) and DT-E148S-K516A-F530A were cloned in B. Subtilis plasmid PSM604 under the subtilisin signal sequence. The expression was effective in both SMS300 and SMS118, but higher yield of 7.1 mg/L was observed in SMS300 compared with 2.1 mg/L in SMS118. Western blot showed that the recombinant protein could be effectively secreted into the culture medium as a 58 ku peptide, and could be degraded into two peptides of 37 ku and 21 ku.

Binding of hepatitis C virus to CD81.

Chronic hepatitis C virus (HCV) infection occurs in about 3 percent of the world's population and is a major cause of liver disease. HCV infection is also associated with cryoglobulinemia, a B lymphocyte proliferative disorder. Virus tropism is controversial, and the mechanisms of cell entry remain unknown. The HCV envelope protein E2 binds human CD81, a tetraspanin expressed on various cell types including hepatocytes and B lymphocytes. Binding of E2 was mapped to the major extracellular loop of CD81. Recombinant molecules containing this loop bound HCV and antibodies that neutralize HCV infection in vivo inhibited virus binding to CD81 in vitro.

[Hystersoscopy: instrumentation and techniques]. / L'isteroscopia: strumentazione e tecniche di esecuzione.

This paper was presented at the 1st Update Course in Hysteroscopy and Microcolpohysteroscopy organised by LAMM and held at the 1st Institute of Obstetrics and Gynecology at Policlinico Umberto I in Rome. The paper is divided into three sections: the first section describes the technical instruments used during hysteroscopy (light source, means of distending the uterine cavity, optic systems); the second reports the technique used in hysteroscopic examination: in particular, the authors underline the importance where necessary (i.e. in young patients with stenosis of the cervical canal and in elderly patients with atrophy of the neck of the uterus or conglutination of the external uterine operning) of preceding dilatation of the cervical canal by the use of endovaginal prostaglandin derivatives in order to render it less traumatic. Moreover, the authors attempt to simplify the technique as much as possible so as to render it a routine or ambulatorial test; the third section describes complications of the hysteroscopic examination, in order of frequency, as well as methods of storing and disinfecting the instruments used in hysteroscopy.

[Use of alpha interferon in microcondylomatosis of the female genitalia]. / Impiego dell' alpha-interferon nella microcondilomatosi dell'apparato genitale femminile.

The Authors report the results of their research into the use of the alpha-interferon in the microcondylomatosis of the female genital apparatus. The therapy was successful in 18% of cases. Considering oncological risk connected with the permanency of the HPV in the uterine portio, the Authors consider they must continue the study on new diagnostic and therapeutic protocols.

Detection in an enzyme immunoassay of an immune response to a recombinant fragment of the 128 kilodalton protein (CagA) of Helicobacter pylori.

The possibility of using a recombinant fragment of the CagA (128 kDa protein) for the diagnosis of Helicobacter pylori infection was evaluated. Following cloning of the gene coding for the CagA, a recombinant fragment of it was expressed in Escherichia coli, purified and used in Western blot and an EIA to screen sera from 82 patients with gastroduodenal disease who underwent endoscopic examination. In Western blot, good correlation was found between the serological data obtained with the recombinant antigen and those obtained using non-purified extracts of Helicobacter pylori. The EIA using the antigen showed a sensitivity of 96.2% and a specificity of 96.6% compared with Western blot. These data indicate that the recombinant protein is a reliable antigen for detection of infections with Helicobacter pylori strains that are associated with disease. The EIA assay described may be used in follow-up of the progression of the illness and the results of therapy.

Molecular characterization of the 128-kDa immunodominant antigen of Helicobacter pylori associated with cytotoxicity and duodenal ulcer.

Helicobacter pylori has been associated with gastritis, peptic ulcer, and gastric adenocarcinoma. We report the nucleotide sequence and expression of an immunodominant antigen of H. pylori and the immune response to the antigen during disease. The antigen, named CagA (cytotoxin-associated gene A), is a hydrophilic, surface-exposed protein of 128 kDa produced by most clinical isolates. The size of the cagA gene and its protein varies in different strains by a mechanism that involves duplication of regions within the gene. Clinical isolates that do not produce the antigen do not have the gene and are unable to produce an active vacuolating cytotoxin. An ELISA to detect the immune response against a recombinant fragment of this protein detects 75.3% of patients with gastroduodenal diseases and 100% of patients with duodenal ulcer (P < 0.0005), suggesting that only bacteria harboring this protein are associated with disease.

Use of antibodies against a synthetic peptide of the E6 protein of human papillomavirus (HPV) type 16 for the diagnosis of genital HPV lesions.

The E6 open reading frame of the human papillomavirus (HPV) 16 codes for a protein of 158 amino acids with a theoretical molecular weight of 19.1 kD. A peptide corresponding to 147-158 amino acids (NH2-RSSRTRRETQLC-COOH) was synthesized, coupled to haemocyanin and used for immunization of rabbits. The antibodies obtained were used for the immunohistochemical analysis of a series of 41 paraffin-embedded biopsies including 29 cases of HPV 16-associated cervical lesions, five HPV 6, four HPV 11, and three HPV 18-associated genital warts. Expression of a reacting molecule (both intranuclear and cytoplasmic) could be demonstrated in 28/29 (96.6%) of the HPV 16 lesions, in 2/5 (40%) of the HPV 6, in 2/4 (50%) of the HPV 11, and in 3/3 of HPV 18 lesions. The intensity of the staining was weak in the HPV 6 and HPV 11 lesions, whereas it was classified as intense in 21/29 (72%) of the E6-positive HPV 16 lesions. Negative staining was almost invariably (5/6, 83%) confined to HPV-non-cervical intraepithelial neoplasia (HPV-NCIN) lesions, only 5/18 (27%) of which showed an intense staining. In contrast, intense staining was associated with CIN; 11/12 (92%) in HPV-CIN I and 8/11 (73%) in HPV-CIN II lesions. In the HPV 16 group, intense reactivity was more frequent in lesions shown to make clinical progression (8/9, 89%) as compared with those which underwent spontaneous regression (10/15, 66.7%). Topography of the immunostaining paralleled the localization of HPV DNA hybridization signals in 20/21 (95%) evaluable HPV 16 cases, in contrast to only 1/3 in HPV 18 cases and in none of the HPV 6 and HPV 11 lesions. These differences between HPV 16 and HPV 6/11 lesions in the staining with the HPV 16 E6 protein antibody might help explain at least some of the differences in their known biological behaviour.

Characterization by mass spectrometry of a recombinant hepatitis delta virus antigen and its proteolytic products.

The recombinant hepatitis delta virus antigen was obtained as a chimaeric protein fused to the C-terminus of the phage MS2 RNA polymerase. Following induction of the temperature-sensitive promoter, two major polypeptides of about 34 kDa and 29 kDa, and two minor peptides about 21 kDa and 18 kDa, were obtained on PAGE. The 34-kDa protein was identified as the expected recombinant protein by confirming 82% of the primary structure using fast-atom-bombardment mass spectrometry. The most represented degradation product, i.e. the 29-kDa polypeptide, was also characterized by means of mass spectrometry and found to be produced by cleavage between amino acids 261 and 265. The presence of two main protein bands, with a similar difference in size, is also a typical feature of delta antigens, both extracted and recombinant, and it is considered to be derived either from heterogeneity of viral sequences, which can encode hepatitis delta antigen proteins of 195 and 214 amino acids, or from proteolysis of a single precursor. Since the data were obtained with a single viral sequence coding for 195 amino acids fused to 106 residues from MS2 polymerase, there is direct evidence that intrinsic structural properties of the protein sequence are able to cause a specific proteolysis resulting in the presence of two major forms, of which the smaller is 35-40 amino acids at the C-terminus. The recombinant protein can be used as an antigenic substitute of viral antigens both for immunoassays and for the preparation of anti-(hepatitis delta virus) antisera.

Adenosine receptors on human leukocytes. IV. Characterization of an A1/Ri receptor.

Adenosine (10(-9)-10(-6) mol/l) and R-phenylisopropyladenosine (10(-9)-10(-7) mol/l) partially inhibited the intracellular accumulation of cyclic AMP induced by isoproterenol, prostaglandin E1, histamine and 5'-N-ethylcarboxamidoadenosine in lymphocytes. In contrast, S-phenylisopropyladenosine, which is a poor agonist of the adenosine A1/Ri receptor, had essentially no inhibitory effect. 8-Phenyltheophylline, in low concentrations that do not inhibit cyclic AMP phosphodiesterase, completely blocked the inhibitory effect of R-phenylisopropyladenosine on the increase in cyclic AMP induced by prostaglandin E1. R-Phenylisopropyladenosine (10(-8)-10(-6) mol/l) also inhibited the cyclic AMP accumulation in lymphocytes induced by forskolin (10(-5) mol/l), which activates adenylate cyclase through direct interaction with the enzyme. We also investigated the presence of the adenosine A1/Ri receptor on human polymorphonuclear leukocytes. R-Phenylisopropyladenosine (3 x 10(-9)-10(-7) mol/l) abolished the stimulating effects of prostaglandin and forskolin on cyclic AMP accumulation in polymorphonuclear leukocytes. This effect was blocked by 8-phenyltheophylline and was not observed with the stereoisomer S-phenylisopropyladenosine. The results support the existence of an A1/Ri receptor that regulates cyclic AMP metabolism of human lymphocytes and polymorphonuclear leukocytes.

Adenosine receptors of human leukocytes--II. Characterization of an inhibitory P-site.

We have investigated the effects of 2',5'-dideoxyadenosine (DDA), 9'-beta-D-arabinofuranosyladenine (ARA), and 9-beta-D-xylofuranosyladenine (XFA), which have been classified as P-site adenosine agonists, on the cyclic adenosine 3',5'-monophosphate (cAMP) metabolism of human lymphocytes and polymorphonuclear leukocytes (PMNs). DDA (10(-5)-2 x 10(-4) M), ARA and XFA caused a dose-dependent decrease in cAMP content of human lymphocytes. In addition to decreasing lymphocyte cAMP levels, DDA, ARA, and XFA markedly inhibited the effects of many adenylate cyclase-stimulating agents including beta-adrenergic stimuli, prostaglandin E1 (PGE1), histamine, adenosine, forskolin and cholera toxin. Theophylline and 3-isobutyl-1-methylxanthine, which are known antagonists of adenosine A1/Ri and A2/Ra receptors, did not modify the inhibiting effects of DDA. Mn2+ (1 mM) increased the sensitivity to inhibition of adenylate cyclase agonists by DDA. We also search for the presence of adenosine P-sites in human PMNs. DDA caused a significant decrease of PMN cAMP levels only at the highest concentrations used (2 x 10(-4) M). In contrast, even low concentrations of DDA (10(-6)-10(-4) M) concentration-dependently blocked the stimulatory effect of PGE1 and forskolin on PMN cAMP accumulation. The results support the existence of a purine P-site that regulates cAMP metabolism of human lymphocytes and PMNs.

Immunolocalization of intermediate filament proteins using antibodies to synthetic peptides.

Synthetic peptides corresponding to amino acid sequences of amino terminal non-alpha helical domains of human cytokeratin 18 and to low molecular weight human neurofilament subunit were used to obtain monospecific antisera. The results of our immunohistochemical investigations confirmed in general the data previously published on the distribution of cytokeratin 18 in human, rat, and calf tissues. The reactivity of the antiserum was abolished after formalin fixation of specimens. Immunolocalization of the neurofilament subunit using our monospecific antiserum was quite variable from species to species in cells of the central and peripheral nervous systems, and also varied as the result of the tissue fixation procedures. In particular, formalin fixation destroyed the immunoreactivity of the recognized epitope. We discuss the advantages and limits of the use of synthetic peptides as immunogens to produce polyclonal antibodies against intermediate filament proteins, with particular attention to the epitope masking phenomena in cytokeratin polypeptides and the phosphorylation of epitopes in neurofilament subunits.