Use of hepatitis B core antigen produced inEscherichia coli to detect immunoglobulin M specific antibodies in an enzyme-linked immunosorbent assay

The antigenic activity of HBcAg produced inEschericha coli and HBcAg from human liver was compared in aμ-specific solid-phase antibody-capture assay for detection of anti-HBc-IgM. HBcAg from liver could be detected in dilutions up to 1∶3, HBcAg fromEscherichia coli in dilutions up to 1∶10, 000. Using HBcAg fromEschericha coli, sera from five patients with acute resolving hepatitis B and sera from four patients with actue hepatitis B who had developed chronic liver disease were tested for anti-HBc-IgM in ELISA. IgM fractions separated out of the same sera by immunoaffinity chromatography were tested for anti-HBc-IgM using a commercially available test. The results were in good agreement with those obtained by ELISA. Anti-HBc-IgM could be detected up to 900 days after onset of disease. Different groups of patients were tested for presence of anti-HBc-IgM in ELISA. Fifty-nine of 60 patients with acute hepatitis B were positive for anti-HBc-IgM at onset of illness. Ten of 16 patients with chronic aggressive hepatitis and seven of 23 HBsAg positive dialysis patients were also positive for anti-HBc-IgM, whereas only two of 12 patients with chronic persistent hepatitis and one of 15 HBsAg positive blood donors (“healthy” carriers of HBsAg) had detectable anti-HBc-IgM.     

Insulin is involved in transcriptional regulation of NKCC and the CFTR Cl− channel through PI3K activation and ERK inactivation in renal epithelial cells

It is is well known that insulin stimulates glucose transport and epithelial Na⁺ channel (ENaC)-mediated Na⁺ reabsorption; however, the action of insulin on Cl^? secretion is not fully understood. In this study, we investigated the action of insulin on Na⁺–K⁺–2Cl^? cotransporter (NKCC)-mediated Cl^? secretion in epithelial A6 cells. Interestingly, insulin treatment remarkably enhanced the forskolin-stimulated Cl^? secretion associated with an increase in apical Cl^? conductance by upregulating mRNA expression of both CFTR and NKCC, although insulin treatment alone had no effect on the basal Cl^? secretion or apical Cl^? conductance without forskolin application. We next elucidated a role of phosphoinositide 3-kinase (PI3K) in the insulin-induced enhancement of the Cl^? secretion, since insulin actually activated PI3K, resulting in activation of Akt, a downstream molecule of PI3K. LY294002 (a PI3K inhibitor) reduced the Cl^? secretion by suppressing mRNA expression of NKCC, whereas insulin still had a stimulatory action on mRNA expression of CFTR even in the presence of LY294002. On the other hand, we found that a MEK inhibitor (PD98059) further enhanced the insulin-stimulated CFTR mRNA expression and the Cl^? secretion in forskolin-stimulated A6 cells and that insulin induced slight, transient activation of ERK followed by significant inactivation of ERK. These observations suggest that: (1) insulin respectively upregulates mRNA expression of NKCC and CFTR through activation of PI3K and inactivation of ERK; (2) insulin signals on mRNA expression of NKCC and CFTR are not enough to stimulate transepithelial Cl^? secretion, but enhance the stimulatory action of cAMP on transepithelial Cl^? secretion.     

Analysis of the interferon system in African patients with acquired immunodeficiency syndrome

Serum interferon and in vitro production of alpha and gamma interferon by peripheral blood leucocytes were examined in 21 African patients with acquired immunodeficiency syndrome (AIDS) and in 15 African patients with AIDS-related complex. Interferon was detected in the serum of 44 % of the patients with AIDS-related complex and in 70 % of the patients with full-blown AIDS, and was characterized as an acid-labile alpha interferon. When compared to healthy blood donors, the interferon response of peripheral blood leucocytes to Newcastle Disease virus was impaired in 7 of 12 patients with AIDS-related complex and in 16 of 20 AIDS patients (p<0.005). Also, production of gamma interferon following stimulation with phytohaemagglutinin was diminished in 5 of 11 patients with AIDS-related complex and in 13 of 17 patients with AIDS (p<0.005). A high correlation was observed between the presence of circulating interferon and decreased in vitro production of gamma interferon, but not of alpha interferon. These results suggest that the impairment of in vitro production of gamma interferon can be used as a preclinical marker of AIDS.     

The Big Five default brain: functional evidence

Recent neuroimaging studies have provided evidence that different dimensions of human personality may be associated with specific structural neuroanatomic correlates. Identifying brain correlates of a situation-independent personality structure would require evidence of a stable default mode of brain functioning. In this study, we investigated the correlates of the Big Five personality dimensions (Extraversion, Neuroticism, Openness/Intellect, Agreeableness, and Conscientiousness) and the default mode network (DMN). Forty-nine healthy adults completed the NEO-Five Factor. The results showed that the Extraversion (E) and Agreeableness (A) were positively correlated with activity in the midline core of the DMN, whereas Neuroticism (N), Openness (O), and Conscientiousness (C) were correlated with the parietal cortex system. Activity of the anterior cingulate cortex was positively associated with A and negatively with C. Regions of the parietal lobe were differentially associated with each personality dimension. The present study not only confirms previous functional correlates regarding the Big Five personality dimensions, but it also expands our knowledge showing the association between different personality dimensions and specific patterns of brain activation at rest.     

Some immunochemical properties of natural antiglobulin factors (homoreactants)

A naturally occurring antiglobulin factor against the Fab-fragment of homologous IgG, contained in the rabbit and human blood serum and γ-globulin preparations, was shown by gelfiltration on Sephadex G-200 to have a molecular weight of about 250,000 daltons. In man this factor does not pass through the placenta in normal pregnancy. Despite differences in the physicochemical and effector properties of 7S IgG and protein with homoreactant activity, the latter has the specific antigenic determinants of IgG. These observations suggest that a complex of IgG with another protein or nonprotein compound possesses homoreactant properties.     

Wogonoside Ameliorates Lipopolysaccharide-Induced Acute Lung Injury in Mice

Wogonoside has been reported to have anti-inflammatory properties. In this study, we evaluated the effect of wogonoside on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Male BALB/c mice with ALI, induced by intranasal instillation of LPS, were treated with wogonoside 1 h prior to LPS exposure. Mice treated with LPS alone showed significantly increased TNF-α, IL-6, and IL-1β levels in the bronchoalveolar lavage fluid (BALF). When pretreated with wogonoside, the TNF-α, IL-6, and IL-1β levels were significantly decreased. Meanwhile, wogonoside significantly inhibited LPS-induced increases in the macrophage and neutrophil infiltration of lung tissues and markedly attenuated myeloperoxidase activity. Furthermore, wogonoside inhibited the TLR4 expression and the phosphorylation of NF-κB p65, and IκB induced by LPS. In conclusion, our results indicate that wogonoside exhibits a protective effect on LPS-induced ALI via suppression of TLR4-mediated NF-κB signaling pathways.     

Impact of socioeconomic risk factors on the seroprevalence of cytomegalovirus infections in a cohort of pregnant Polish women between 2010 and 2011

The purpose of this investigation was to perform an evaluation of the prevalence and socioeconomic risk factors for human cytomegalovirus (HCMV) infections in a cohort of Polish pregnant women between 2010 and 2011. HCMV-specific IgG and IgM antibody levels were assayed with enzyme-linked immunosorbent assay (ELISA) tests in serum samples collected from 1,250 pregnant women attending outpatient obstetric clinics and hospitalized at two hospitals in Lodz. The seroprevalence of anti-HCMV IgG and IgM antibodies was 62.4 and 2.2 %, respectively, and differed significantly between age-stratified groups (p?≤?0.05). The highest IgG prevalence was observed in women above 36 years of age (76.2 %) and IgM in adolescent women aged 16–20 years (6.0 %). Of the various socioeconomic factors, age above 36 years, basic and professional education, and offspring were significantly associated with HCMV IgG prevalence rates (PRs; 1.89, 1.80, and 1.56, respectively). Financial status, occupational risk related to contact with children, and transfusions were not related to the prevalence of IgG antibodies. The IgM prevalence was not associated with any of the analyzed risk factors. A slightly higher prevalence was observed in women who were transfused in the past, but the relationship was not significant. The current data have revealed a decrease in HCMV IgG seroprevalence in our region during recent years (62.4 vs. 76.7 %). Basic and professional education, as well as bringing up offspring, were determined as significant risk factors for HCMV infections in Polish pregnant women [risk ratio (RR) 1.20 and 1.17, respectively], suggesting that the primary and secondary prophylaxis of cytomegaly is necessary during pregnancy, even if screening is not mandatory.     

Rapid separation of immunoglobulin M by immunoaffinity chromatography for detection of specific antibodies to rubella andTreponema pallidum

A rapid and easy method for isolating IgM from serum specimens in order to detect specific antibodies againstTreponema pallidum and rubella virus by routine serologic procedures is described. Serum IgM was isolated by immunoaffinity chromatography using anti-human IgM antibodies covalently bound to controlled-pore glass beads in a microcolumn. The final concentration of the IgM in the samples tested amounted to at least 16 % (average 32 %) of the original concentration (corresponding to a serum dilution of 1∶<8). IgG contamination did not exceed 0.38 % of the original serum concentration. The capacity of the column was stable for at least 50 absorption/ elution cycles. The new technique enables rapid and reliable detection of specific IgM by the rubella hemagglutination inhibition andTreponema pallidum hemagglutination tests.     

New insights into the molecular phylogeny of Balantidium (Ciliophora,Vetibuliferida) based on the analysis of new sequences of species from fish hosts

We obtained sequences of the small subunit ribosomal RNA (rRNA) for two new isolates of Balantidium from fishes, Balantidium polyvacuolum and Balantidium ctenopharingodoni. This is the first introduction of molecular data of Balantidium species from fish hosts in the phylogenetic analyses of the ciliate subclass Trichostomatia. Despite the fact that these species share morphological characteristics common to other species of Balantidium, the phylogenetic analysis of their sequences has shown that they are to be placed in a different branch closely related to the so-called Australian clade. Thus, our results indicate that the genus Balantidium is polyphyletic and possibly should be represented by two different genera; however, the analysis of more species from other poikilothermic hosts (amphibians, reptiles) should be made before a revised taxonomical proposal could be made.     

Evaluation of the sensitivity of IgG and IgM ELISA in detecting Schistosoma mansoni infections in a low endemicity setting

Schistosomiasis is a major public health concern, with 200 million people infected worldwide. In Brazil, this disease has been reported in 19 states, and its prevalence in the city of Barra Mansa in Rio de Janeiro State is 1 %. The parasitological diagnostic methods currently available in these areas lack sensitivity; however, enzyme-linked immunosorbent assays (ELISAs) have been employed successfully for the diagnosis of schistosomiasis by using antibodies against antigens of Schistosoma mansoni adult worms and eggs, and for the detection of circulating antigens. The objective of this study was to determine systematically the prevalence of S. mansoni infection in the peripheral areas of Barra Mansa. A cross-sectional study was conducted from April to December 2011 by using probabilistic sampling that collected 610 fecal samples and 612 serum samples. ELISA-IgG with total extracts and ELISA-IgM with trichloroacetic acid-soluble fractions were employed to detect antibodies against S. mansoni and were compared with the Kato–Katz and Hoffman parasitological techniques. Among the individuals studied, anti-S. mansoni antibodies were detected in 11.16 % (n?=?71) by ELISA-IgG and in 20.75 % (n?=?132) by ELISA-IgM, while the parasitological techniques showed 0.82 % (n?=?5) positivity. The agreement between the two ELISA tests was 85.38 % (n?=?543), and 8.65 % (n?=?55) of the serum samples showed positive results in both tests. The higher positivity of the ELISA-IgM test corroborates the results of previous reports and indicates that the test may be a useful tool in epidemiological studies, particularly in areas of low endemicity for S. mansoni.     

Effect of hydrocortisone on the stages of immunogenesis

The effect of hydrocortisone was studied on the following stages of immunogenesis: migration of hematopoietic stem cells from the bone marrow; migration of B lymphocyte precursors of antibody-forming cells; cooperative interaction of T and B lymphocytes in the primary immune response to antigenic stimulation by sheep's red cells. Experiments were carried out on F₁(CBA x C57BL) mice. Hydrocortisone, in doses not inhibiting proliferation of hematopoietic cells, had a marked immunodepressive effect which was the resultant of inhibition between different stages of immunogenesis: migration of stem cells and B lymphocytes and cooperation between T and B lymphocytes.     

MCMV avoidance of recognition and control by NK cells

Natural killer (NK) cells play an important role in virus control during infection. Many viruses have developed mechanisms for subversion of NK cell responses. Murine cytomegalovirus (MCMV) is exceptionally successful in avoiding NK cell control. Here, we summarize the major MCMV evasion mechanisms targeting NK cell functions and their role in viral pathogenesis. The mechanisms by which NK cells regulate CD8⁺ T cell response, particularly with respect to the role of NK cell receptors recognizing viral antigens, are discussed. In addition, we discuss the role of NK cell receptors in generation and maintenance of memory NK cells. Final part of this review illustrates how the NK cell response and its viral regulation can be exploited in designing recombinant viral vectors able to induce robust and protective CD8⁺ T cell response.     

Use of the enzyme-linked immunosorbent assay for the early diagnosis ofMycoplasma pneumoniae infection

IgM and IgG antibodies toMycoplasma pneumoniae were measured in 147 sera from four groups of patients by means of an indirect enzyme-linked immunosorbent assay (ELISA) and the results compared with those obtained by other methods. A good correlation was demonstrated between the complement fixation test and ELISA-IgM and to a lesser extent ELISA-IgG; for the metabolic inhibition test the reverse was the case. The indirect haemagglutination test appeared to detect mainly IgM antibodies. Low levels of IgM antibodies were dectected by ELISA in 60 sera of children not suffering from pneumonia. However, if only high titres (> 800) were regarded as indicative ofMycoplasma pneumoniae infection, a presumptive diagnosis could have been made in 42 of 73 single acute phase sera from patients. Comparable results were obtained with IHA. The diagnostic level of IgM antibodies was reached during the second week of the disease. It is concluded that examination of a single serum sample by either ELISA-IgM or IHA may assist in early diagnosis ofMycoplasma pneumoniae infection.     

An anti-human immunoglobulin M monoclonal antibody for detection of antibodies toToxoplasma gondii

An anti-human μ-chain monoclonal antibody, Tibi 82, was produced and tested for specificity by radioimmunoassay. Its reliability in detecting IgM antibodies toToxoplasma gondii was tested by two reverse immunosorbent methods (IgM-ISAGA and IgM-SPIHA) and the IgM fluorescent antibody test (IgM-IFA) on 400 sera. Whereas the results obtained with Tibi 82 and with two polyclonal reagents were highly correlated, the third commercial polyclonal reagent provided many false negative results. By standardizing IgM binding, Tibi 82 allowed the comparison of IgM-ISAGA with IgM-SPIHA on 100 sera: 17 % of the sera tested showed discrepancies due to the different toxoplasma antigens used. Although Tibi 82 facilitated the reading of results and enhanced sensitivity and specificity of the double-sandwich IgM-IFA method, the latter was still less sensitive than IgM-ISAGA with Tibi 82. Tests with the monoclonal antibody were consistently superior to tests with polyclonal antibodies.     

CMV-encoded Fcγ receptors: modulators at the interface of innate and adaptive immunity

The constant region of IgG antibodies mediates antiviral activities upon engaging host Fcγ receptors (FcγRs) expressed by a variety of immune cells, such as antibody-dependent cellullar cytotoxcity (ADCC) executed by natural killer (NK)cells. Human cytomegalovirus (HCMV) is unique among viruses by encoding also an array of several Fcγ-binding glycoproteins with cell surface disposition and concomitant incorporation into the virion. Evidence is increasing that the virus-encoded Fcγ receptors differ in their Fcγ binding mode but effectively operate as adversaries of host FcγRs since they are able to prevent IgG-mediated triggering of activating host FcγRs, i.e., FcγRI, FcγRIIA, and FcγRIIIA. Here we discuss virus-encoded FcγRs as the first known HCMV inhibitors of IgG-mediated immunity which could account for the limited efficacy of HCMV hyperimmune globulin in clinical settings. A better understanding of their molecular mode of action opens up new perspectives for improving IgG therapies against HCMV disease.     

Intravenous immunoglobulin-mediated immunosuppression and the development of an IVIG substitute

Immunoglobulins are glycoproteins produced by the cells of the immune system. Their primary function is to protect the body from pathogenic infection. Moreover, a concentrated polyclonal mixture of immunoglobulin G (IgG), the so-called intravenous IgG (IVIG), has been used to treat various chronic and systemic disorders of the immune system. Studies on the effects of IVIG in autoimmune disease models have revealed that IgG Fc fragments confer protection against various autoimmune diseases. The identification of this IgG Fc immunomodulatory component is important for the development of IVIG substitutes. The focus of this review is to introduce one of the Fc regulatory entities and to provide a summary of the current knowledge of the putative general mechanisms underlying IVIG activity in vivo on the basis of these Fc fragments. We also address the recent insights into several approaches for the development of IVIG substitutes.     

Enzyme-linked immunosorbent assay for detection of solubleToxoplasma gondii antigen in acute-phase toxoplasmosis

Sixty-two sera from 51 patients with lymphadenopathy presumed to be due to acute-phase toxoplasmosis were tested for specific IgM class antibodies by both the immunofluorescence antibody toToxoplasma gondii in sera were first dissociated in 3M NaSCN. Antigen attached to the solid phase was detected with enzyme-coupled IgG antibody toToxoplasma antibody toToxoplasma gondii in sera were first dissociated in 3M NaSCN. Antigen attached to the solid phase was detected with enzyme-coupled IgG antibody toToxoplasma gondii. Neither hepatitis B surface antigen nor antigen ofMycoplasma pneumoniae, rubella, cytomegalovirus or herpes simplex virus interfered with this ELISA. Soluble antigen was detected in 13(30%) of 42 IgM-positive acute-phase toxoplasmosis patients and in only one of 20 sera cleared of IgM. None of an additional 44 IgM-negative patients with low IgG titres had a positive result in the antigen ELISA. Follow-up studies in four acute-phase toxoplasmosis patients showed that the soluble antigen cleared in all cases before the specific IgM antibodies. Simultaneous detection of IgM antibodies toToxoplasma gondii and soluble antigen would thus seem to indicate an early stage of the infection.     

Local effect of single stranded polyadenylic acid on passive cutaneous anaphylaxis in mice

Single stranded polyadenylic acid (Poly A) administered locally inhibited passive cutaneous anaphylaxis in mice. In experiments performed by equilibrium dialysis Poly A was able to bind histamine. The association constant of the reaction was determined,K _α=1.3±0.2×10⁵ l/M. One Poly A molecule can bind maximally two molecules of histamine dichloride. Poly A inhibited the antigen-induced release of histamine from the peritoneal rat mast cells when it was given together with sensitizing antibodies.     

Subcellular fractions in rubella immunoassays

Rubella virus-infected cells were fractionated by differential and sucrose gradient centrifugations. Rubella virus antigens distributed into all fractions but particulate material in the 100, 000×g pellet was shown to be enriched about two-fold for rubella virus antigen. Similarly, sucrose gradient fractions for rough endoplasmic reticulum and smooth cellular membranes were enriched for rubella virus antigens. The 100, 000 ×g pellet and the isolated cellular membranes proved to be useful when different fractions were used in solid-phase immunoassays for rubella virus-specific IgG or IgM. These fractions were equal in quality of the semipurified rubella virus preparations in the IgG assays but inferior to those in the IgM assays. However, simultaneous use of 35/25 % sucrose fractions from infected and non-infected cells reveals non-specific binding of IgM to the antigens and renders the IgM tests more specific for rubella virus.