Establishment of a panel of in-house polyclonal antibodies for the diagnosis of enterovirus infections

The aim of this study was to establish a reliable method of virus detection for the diagnosis of critical enterovirus infections such as acute infective encephalitis, encephalomyelitis and myocarditis. Because histopathological and immunohistochemical analyses of paraffin-embedded tissues play an important role in recognizing infectious agents in tissue samples, six in-house polyclonal antibodies raised against three representative enteroviruses using an indirect immunofluorescence assay and immunohistochemistry were examined. This panel of polyclonal antibodies recognized three serotypes of enterovirus. Two of the polyclonal antibodies were raised against denatured virus particles from enterovirus A71, one was raised against the recombinant VP1 protein of coxsackievirus B3, and the other for poliovirus type 1 were raised against denatured virus particles, the recombinant VP1 protein and peptide 2C. Western blot analysis revealed that each of these antibodies recognized the corresponding viral antigen and none cross-reacted with non-enteroviruses within the family Picornaviridae. However, all cross-reacted to some extent with the antigens derived from other serotypes of enterovirus. Indirect immunofluorescence assay and immunohistochemistry revealed that the virus capsid and non-structural proteins were localized in the cytoplasm of affected culture cells, and skeletal muscles and neurons in neonatal mice experimentally-infected with human enterovirus. The antibodies also recognized antigens derived from recent clinical isolates of enterovirus A71, coxsackievirus B3 and poliovirus. In addition, immunohistochemistry revealed that representative antibodies tested showed the same recognition pattern according to each serotype. Thus, the panel of in-house anti-enterovirus polyclonal antibodies described herein will be an important tool for the screening and pathological diagnosis for enterovirus infections, and may be useful for the classification of different enterovirus serotypes, including coxsackieviruses A and B, echoviruses, enterovirus A71 and poliovirus.

Enterovirus-infected β-cells induce distinct response patterns in BDCA1+ and BDCA3+ human dendritic cells

Enteroviruses often cause mild disease, yet are also linked to development of autoimmune diabetes. Dendritic cells (DCs) shape both innate and adaptive immune responses, including anti-viral responses. How different human DC subsets shape anti-viral responses, whether they have complementary or overlapping functions and how this relates to autoimmune responses is largely unknown. We used enterovirus-infected β-cells and freshly isolated human myeloid DC (mDC) subsets as a model for autoimmune type 1 diabetes. Our data show that both the BDCA1⁺ and BDCA3⁺ mDC subsets engulf mock- as well as virus-infected β-cells, albeit BDCA1⁺ mDCs are more efficient. Uptake of enterovirus-infected, but not mock-infected cells, activated both DC subsets as indicated by the induction of co-stimulatory molecules and secretion of type I and type III interferons. Both subsets produced similar amounts of interferon-α, yet the BDCA3⁺ DC were superior in IFN-λ production. The BDCA1⁺ mDCs more strongly upregulated PD-L1, and were superior in IL-12 and IL-10 production as compared to the BDCA3⁺ DC. Despite lack of IL-12 production by the BDCA3+ DC, both BDCA1⁺ and BDCA3⁺ DCs activated T cells in allogeneic mixed lymphocyte reaction towards a Th1-type reactivity while suppressing Th2-associated cytokines.

The stress granule protein G3BP1 recruits protein kinase R to promote multiple innate immune antiviral responses

Stress granules (SGs) are cytoplasmic storage sites containing translationally silenced mRNPs that can be released to resume translation after stress subsides. We previously showed that poliovirus 3C proteinase cleaves the SG-nucleating protein G3BP1, blocking the ability of cells to form SGs late in infection. Many other viruses also target G3BP1 and inhibit SG formation, but the reasons why these functions evolved are unclear. Previously, we also showed a link between G3BP1-induced SGs and protein kinase R (PKR)-mediated translational control, but the mechanism of PKR interplay with SG and the antiviral consequences are unknown. Here, we show that G3BP1 exhibits antiviral activity against several enteroviruses, whereas truncated G3BP1 that cannot form SGs does not. G3BP1-induced SGs are linked to activation of innate immune transcriptional responses through NF-κB and JNK. The G3BP1-induced SGs also recruit PKR and other antiviral proteins. We show that the PXXP domain within G3BP1 is essential for the recruitment of PKR to SGs, for eIF2α phosphorylation driven by PKR, and for nucleating SGs of normal composition. We also show that deletion of the PXXP domain in G3BP1 compromises its antiviral activity. These findings tie PKR activation to its recruitment to SGs by G3BP1 and indicate that G3BP1 promotes innate immune responses at both the transcriptional and translational levels and integrates cellular stress responses and innate immunity.

IMPORTANCE

Stress granules appear during virus infection, and their importance is not well understood. Previously, it was assumed that they were nonfunctional artifacts associated with cellular stress. PKR is a well-known antiviral protein; however, its regulation in cells is not well understood. Our work links cellular stress granules with activation of PKR and other innate immune pathways through the activity of G3BP1, a critical stress granule component. The ability of stress granules and G3BP1 to activate PKR and other innate immune transcriptional responses indicates that G3BP1 is an antiviral protein. This work helps to refine a longstanding paradigm indicating stress granules are inert structures and explains why G3BP1 is subverted by many viruses to promote a productive infection.

[Production of the polyclonal enterovirus antibodies of chicken (IgY) and its evaluation as alternative to the rabbit enterovirus neutralizing sera]

Experimental data show the usefulness of the Leghorn chicken as a producer of the enterovirus neutralizing antibodies (IgY). The resulting serum is not inferior to the specific activity of the commercial rabbit enterovirus diagnostic sera (EDS) in the neutralization reaction. The IgY have lower backgrounds than mammalian IgG and do not cause toxic effect to cell culture. Compared with the conventional manufacturing method EDS IgY, preparation process is much more effective: the number of serum producers is significantly lower, whereas the yield of the product is higher. Reduction of the volume of the immunogens, immunization cycle, and number of injections is also an advantage of this manufacturing method.

Synthetic peptides for efficient discrimination of anti-enterovirus antibodies at the serotype level

Enteroviruses are important human pathogens, causing a broad spectrum of diseases from minor common colds to fatal myocarditis. However, certain disease syndromes are caused by one or few serotypes. Serotype identification is difficult due to the laborious neutralization tests that lack of sensitivity, while in commercial ELISAs homotypic antibodies' activities are largely masked by the recognition of genera-specific epitopes by heterotypic antibodies. In the present study homotypic assays were developed with the ability to discriminate different enterovirus serotypes. Seventy-three children sera, positive for IgM antibodies against enterovirus genus and 49 healthy children were examined for the presence of antibodies against 14 synthetic peptides derived from a non-conserved region of the VP1 protein of coxsackieviruses B2, B3, B4, B5, A9, A16, A24, echoviruses 6, 7, 9, 11, 30, enterovirus 71 and parechovirus 1. 50% of the anti-enterovirus IgM positive sera (>150 BU) reacted with the peptides with the majority of them to preferentially recognize one of them, supporting the homotypic nature of our assay. Inhibition studies yielded homologous inhibition rates 67-95% suggesting that specific peptide recognition actually occurred. The diagnostic value of our assay was tested in blood samples drawn over a 1.5-year period from a 5-year old patient. The anti-enterovirus reactivity was clearly attributed to echovirus serotype 11. The IgM/IgG antibody ratio was reversed 4 months later and subsequently IgM antibodies dropped below the cutoff point. In this paper we demonstrate that our assay can be used to discriminate between antibodies targeting different enterovirus serotypes.

Antibodies to islet cell autoantigens, rotaviruses and/or enteroviruses in cord blood and healthy mothers in relation to the 2010-2011 winter viral seasons in Israel: a pilot study

AIMS

To determine whether antivirus and/or islet cell antibodies can be detected in healthy pregnant mothers without diabetes and/or their offspring at birth in two winter viral seasons.

METHODS

Maternal and cord blood sera from 107 healthy pregnant women were tested for islet cell autoantibodies using radioligand binding assays and for anti-rotavirus and anti-CoxB3 antibody using an enzyme-linked immunosorbent assay.

RESULTS

Glutamic acid decarboxylase (GAD)65 autoantibodies and rotavirus antibodies, present in both maternal and cord blood sera, correlated with an odds ratio of 6.89 (95% CI: 1.01-46.78). For five, 22 and 17 pregnancies, antibodies to GAD65, rotavirus and CoxB3, respectively, were detected in cord blood only and not in the corresponding maternal serum. In 10 pregnancies, rotavirus antibody titres in the cord blood exceeded those in the corresponding maternal serum by 2.5-5-fold. Increased antibody titres after the 20(th) week of gestation suggested CoxB3 infection in one of the 20 pregnancies and rotavirus in another.

CONCLUSION

The concurrent presence of GAD65 antibodies in cord blood and their mothers may indicate autoimmune damage to islet cells during gestation, possibly caused by cross-placental transmission of viral infections and/or antivirus antibodies. Cord blood antibody titres that exceed those of the corresponding maternal sample by >2.5-fold, or antibody-positive cord blood samples with antibody-negative maternal samples, may imply an active in utero immune response by the fetus.

[Immunoprotective effect of inactivated coxsackievirus A16 vaccine in mice]

This study aims to construct inactivated coxsackievirus A16 (CVA16) vaccine and to investigate its protective effect in ICR mice. A clinical isolate of CVA16, 521-01T, was cultured in VERO cells, inactivated by formaldehyde, and purified by ultracentrifugation for vaccine preparation. Purity and other characteristics of the vaccine were determined by SDS-PAGE and Western blot. Female ICR mice were subcutaneously inoculated with inactivated CVA16 or Al(OH)3-absorbed CVA16, followed by booster immunization at the end of 2 and 4 weeks. CVA16-specific IgG titers in serum were determined by ELISA, and titers of neutralizing antibodies were determined by viral neutralization assay. The immunity of T lymphocytes was evaluated by IFN-gamma ELISPOT assay. The protective effect was evaluated by challenging the neonatal offspring (< 48 hours) of vaccinated female mice with 1 000 LD50 of CVA16 521-01T. The mortality rates of different groups were compared. The results showed that Al(OH)3 +CVA16 could induce high titers of specific IgG antibodies in ICR mice. After being boosted two times, the serum IgG antibody titer could reach up to 1 : 1 x 10(5) (P = 0.000), and neutralizing antibody titer was higher than 1 : 256. Additionally, more spot forming cells were induced in the immunized groups than in the negative controls. The maternal antibodies showed protective effect in 100% of the neonatal mice challenged with 1 000 LD50 of CVA16 521-01T. The inactivated CVA16 vaccine has ideal immunogenicity and immunoprotective effect. This research lays a foundation for the development and evaluation of CVA16 vaccines.

Modelling seasonal HFMD with the recessive infection in Shandong, China

Hand, foot and mouth disease (HFMD) is one of the major public-health problems in China. Based on the HFMD data of the Department of Health of Shandong Province, we propose a dynamic model with periodic transmission rates to investigate the seasonal HFMD. After evaluating the basic reproduction number, we analyze the dynamical behaviors of the model and simulate the HFMD data of Shandong Province. By carrying out the sensitivity analysis of some key parameters, we conclude that the recessive subpopulation plays an important role in the spread of HFMD, and only quarantining the infected is not an effective measure in controlling the disease.

[Monitoring of enterovirus circulation in Irkutsk region]

AIM

Monitoring of circulation of enteroviruses (EVI) in Irkutsk Region and study of regional specter of circulating enteroviruses.

MATERIALS AND METHODS

1419 samples from patients with suspected EVI, contact in foci ofenterovirus infection, acute intestine infections and 964 samples of sewage water were studied in total. In 2011 isolation of viral agents from 97 samples positive on enterovirus by RT-PCR from patients with preliminary EVI diagnosis and 5 samples of sewage water of Irkutsk city was carried out. Transplantable line of human rhabdomyosarcoma RD cell culture was used for isolation of enteroviruses. Infection of cells and 2 serial passages of the studied material were carried out. The isolates were typed in neutralization reaction (NR) with a set of 32 diagnostic type-specific immune sera against viral poliomyelitis I-III; Coxsackie B1-6; Coxsackie A2, A4, A7, A9, A10; ECHO 68 - 71; ECHO 2, 4, 7, 8, 9, 12, 16, 20, 25, 26, 27, 29, 31, 33.

RESULTS

In 2011 circulation of enterovirus serotypes that were previously absent on the territory of the region was established: ECHO 68, ECHO 70, ECHO 71. These strains were isolated from patients, circulation of ECHO 70 serotype was established also in samples of sewage water. The analysis of enterovirus landscape carried out showed the possibility of complication of epidemic situation on the territory of the region due to change of serovariants of causative agents of non-polioenterovirus infections and detection ofepidemically significant enteroviruses - ECHO 68, 70 and 71 serotypes.

CONCLUSION

Determination of specter ofenterovirus serotypes, detection of serotypes that had not previously circulated in Irkutsk Region allows to prognose epidemic situation on morbidity of enterovirus infections and timely develop and make decisions for ensuring epidemiologic welfare of the population.

Differential susceptibility and response of primary human myeloid BDCA1(+) dendritic cells to infection with different Enteroviruses

Coxsackie B viruses (CVBs) and echoviruses (EVs) form the Human Enterovirus-B (HEV-B) species within the family Picornaviridae. HEV-B infections are widespread and generally cause mild disease; however, severe infections occur and HEV-B are associated with various chronic diseases such as cardiomyopathy and type 1 diabetes. Dendritic cells (DCs) are the professional antigen-presenting cells of our immune system and initiate and control immune responses to invading pathogens, yet also maintain tolerance to self-antigens. We previously reported that EVs, but not CVBs, can productively infect in vitro generated monocyte-derived DCs. The interactions between HEV-B and human myeloid DCs (mDCs) freshly isolated from blood, however, remain unknown. Here, we studied the susceptibility and responses of BDCA1(+) mDC to HEV-B species and found that these mDC are susceptible to EV, but not CVB infection. Productive EV7 infection resulted in massive, rapid cell death without DC activation. Contrary, EV1 infection, which resulted in lower virus input at the same MOI, resulted in DC activation as observed by production of type I interferon-stimulated genes (ISGs), upregulation of co-stimulatory and co-inhibitory molecules (CD80, CD86, PDL1) and production of IL-6 and TNF-α, with a relative moderate decrease in cell viability. EV1-induced ISG expression depended on virus replication. CVB infection did not affect DC viability and resulted in poor induction of ISGs and CD80 induction in part of the donors. These data show for the first time the interaction between HEV-B species and BDCA1(+) mDCs isolated freshly from blood. Our data indicate that different HEV-B species can influence DC homeostasis in various ways, possibly contributing to HEV-B associated pathology.

Antibody cross-reactivity and the viral aetiology of type 1 diabetes

Type 1 diabetes (T1D) is caused by the destruction of insulin-producing pancreatic β cells by the patient's immune system. While the underlying genetics and immunopathology are fairly well characterized, the environmental trigger remains unidentified. Numerous studies have centred on the role of enteroviruses as aetiological factors that could initiate or accelerate T1D development. The most convincing evidence to date consists of an array of reports documenting the presence of enteroviral nucleic acids in peripheral blood at diagnosis. A prominent hypothesis is that enteroviruses may infect the pancreatic islets and thus be responsible for the islet-specific up-regulation of MHC class I that is commonly observed, possibly enabling T cell recognition and cytotoxicity. Past immunohistochemical studies have indeed shown that antibodies binding the enteroviral capsid protein VP1 preferentially stain the pancreatic β cells from diabetic individuals. New data now indicate that the VP1 antibody used in these studies cross-reacts with mitochondrial proteins.

[Comparison of three detection methods for neutralizing antibodies induced by Coxsackievirus A16 vaccine]

OBJECTIVE

To develop a comprehensive detection platform for immunoprotection of inactivated coxsackievirus A16(CA16) vaccine based on the neutralizing antibodies tested through competitive inhibition ELISA, micro-cytopathic effect neutralization test and neonatal mice challenge protection test.

METHODS

The female BALB/c mice, SD rats and Hartley guinea pigs were inoculated intraperitoneally at 0, 4, 6, 8 weeks with the three vaccine candidates which were made from 3726, 4430 and 4432 virus absorbed on aluminium adjuvant. Immune sera were taken at 0, 4, 6, 8, 10 weeks and serum neutralizing antibodies were evaluated by competitive inhibition-ELISA, micro-cytopathic effect neutralization test and neonatal mice challenge protection test, respectively. The relationships of the three methods were analyzed by SPSS16.0 statistical software.

RESULTS

The level of neutralizing antibodies reached the peak after the second booster. The correlation coefficient was 0.861 between competitive inhibition-ELISA and micro-cytopathic effect neutralization test, 0.8 between competitive inhibition-ELISA and neonatal mice challenge protection test and 0.89 between micro-cytopathic effect neutralization test and neonatal mice challenge protection test.

CONCLUSION

A comprehensive detection system through competitive inhibition ELISA, micro-cytopathic effect neutralization test and neonatal mice challenge protection test measuring the neutralizing antibodies in immune sera has been constructed. The competitive inhibition-ELISA is superior to "golden standards" in speed, sensitivity, throughput and price, which may have great application prospect.

Human SCARB2 transgenic mice as an infectious animal model for enterovirus 71

Enterovirus 71 (EV71) and coxsackievirus (CVA) are the most common causative factors for hand, foot, and mouth disease (HFMD) and neurological disorders in children. Lack of a reliable animal model is an issue in investigating EV71-induced disease manifestation in humans, and the current clinical therapies are symptomatic. We generated a novel EV71-infectious model with hSCARB2-transgenic mice expressing the discovered receptor human SCARB2 (hSCARB2). The challenge of hSCARB2-transgenic mice with clinical isolates of EV71 and CVA16 resulted in HFMD-like and neurological syndromes caused by E59 (B4) and N2838 (B5) strains, and lethal paralysis caused by 5746 (C2), N3340 (C4), and CVA16. EV71 viral loads were evident in the tissues and CNS accompanied the upregulated pro-inflammatory mediators (CXCL10, CCL3, TNF-α, and IL-6), correlating to recruitment of the infiltrated T lymphocytes that result in severe diseases. Transgenic mice pre-immunized with live E59 or the FI-E59 vaccine was able to resist the subsequent lethal challenge with EV71. These results indicate that hSCARB2-transgenic mice are a useful model for assessing anti-EV71 medications and for studying the pathogenesis induced by EV71.

Study of the integrated immune response induced by an inactivated EV71 vaccine

Enterovirus 71 (EV71), a major causative agent of hand-foot-and-mouth disease (HFMD), causes outbreaks among children in the Asia-Pacific region. A vaccine is urgently needed. Based on successful pre-clinical work, phase I and II clinical trials of an inactivated EV71 vaccine, which included the participants of 288 and 660 respectively, have been conducted. In the present study, the immune response and the correlated modulation of gene expression in the peripheral blood mononuclear cells (PBMCs) of 30 infants (6 to 11 months) immunized with this vaccine or placebo and consented to join this study in the phase II clinical trial were analyzed. The results showed significantly greater neutralizing antibody and specific T cell responses in vaccine group after two inoculations on days 0 and 28. Additionally, more than 600 functional genes that were up- or down-regulated in PBMCs were identified by the microarray assay, and these genes included 68 genes associated with the immune response in vaccine group. These results emphasize the gene expression profile of the immune system in response to an inactivated EV71 vaccine in humans and confirmed that such an immune response was generated as the result of the positive mobilization of the immune system. Furthermore, the immune response was not accompanied by the development of a remarkable inflammatory response.

Clinical Trial Registration: NCT01391494 and NCT01512706.

Autoimmune myocarditis, valvulitis, and cardiomyopathy

Myocarditis and valvulitis are inflammatory diseases affecting myocardium and valve. Myocarditis, a viral-induced disease of myocardium, may lead to dilated cardiomyopathy and loss of heart function. Valvulitis leads to deformed heart valves and altered blood flow in rheumatic heart disease. Animal models recapitulating these diseases are important in understanding the human condition. Cardiac myosin is a major autoantigen in heart, and antibodies and T cells to cardiac myosin are evident in inflammatory heart diseases. This unit is a practical guide to induction and evaluation of experimental autoimmune myocarditis (EAM) in several mouse strains and the Lewis rat. Purification protocols for cardiac myosin and protocols for induction of EAM by cardiac myosin and its myocarditis-producing peptides, and coxsackievirus CVB3, are defined. Protocols for assessment of myocarditis and valvulitis in humans and animal models provide methods to define functional autoantibodies targeting cardiac myosin, β-adrenergic, and muscarinic receptors, and their deposition in tissues.

Expression of the enteroviral capsid protein VP1 in the islet cells of patients with type 1 diabetes is associated with induction of protein kinase R and downregulation of Mcl-1

AIMS/HYPOTHESIS

Immunohistochemical staining reveals that the enteroviral capsid protein VP1 is present at higher frequency in the insulin-containing islets of patients with recent-onset type 1 diabetes than in controls. This is consistent with epidemiological evidence suggesting that enteroviral infection may contribute to the autoimmune response in type 1 diabetes. However, immunostaining of VP1 is not definitive since the antibody widely used to detect the protein (Clone 5D8/1) might also cross-react with additional proteins under some conditions. Therefore, we sought to verify that VP1 immunopositivity correlates with additional markers of viral infection.

METHODS

Antigen immunoreactivity was examined in formalin-fixed, paraffin-embedded, pancreases from two different collections of type 1 diabetes and control cases: a historical collection from the UK and the nPOD (network of Pancreatic Organ donors with Diabetes) cohort from the USA.

RESULTS

VP1 immunoreactivity was present in ~20% of insulin-containing islets of both cohorts under stringent conditions but was absent from insulin-deficient islets. The presence of VP1 was restricted to beta cells but only a minority of these contained the antigen. The innate viral sensor, protein kinase R (PKR) was upregulated selectively in beta cells that were immunopositive for VP1. The anti-apoptotic protein myeloid cell leukaemia sequence-1 (Mcl-1) was abundant in beta cells that were immunonegative for VP1 but Mcl-1 was depleted in cells containing VP1.

CONCLUSIONS/INTERPRETATION

The presence of immunoreactive VP1 within beta cells in type 1 diabetes is associated with a cellular phenotype consistent with the activation of antiviral response pathways and enhanced sensitivity to apoptosis. However, definitive studies confirming whether viral infections are causal to beta cell loss in human diabetes are still awaited.

[Oncolytic enteroviruses]

Increasing information concerning molecular biology of viruses and virus-cell interactions makes it possible to use viruses as a tool in effort to treat cancer diseases. As a rule, tumor cells are highly sensitive to viruses that may be used in cancer therapy. Therewith, applications of viral oncolysis in treatment of cancer diseases assume maximum possible safety of used viruses for patient and environment. Human enteroviruses are one of the most convenient sources to generate oncolytic viruses. Many of enteroviruses are non-pathogenic for humans or cause mild disease. Progress in genetic engineering permits to develop attenuated enterovirus variants with high safety and selectivity. This review focuses on the main members of Enterovirus genus, such as Coxsackieviruses, and vaccine strains as promising source for development of oncolytic agents, applicable for cancer therapy. It reviews data concerning recently developed and tested oncolytic variants of enteroviruses and discusses perspectives of their application in cancer therapy and problems, concerning their improvement and practical use.

Challenges to licensure of enterovirus 71 vaccines

Human enteroviruses usually cause self-limited infections except polioviruses and enterovirus 71 (EV71), which frequently involve neurological complications. EV71 vaccines are being evaluated in humans. However, several challenges to licensure of EV71 vaccines need to be addressed. Firstly, EV71 and coxsackievirus A (CA) are frequently found to co-circulate and cause hand-foot-mouth disease (HFMD). A polyvalent vaccine that can provide protection against EV71 and prevalent CA are desirable. Secondly, infants are the target population of HFMD vaccines and it would need multi-national efficacy trials to prove clinical protection and speed up the licensure and usage of HFMD vaccines in children. An international network for enterovirus surveillance and clinical trials is urgently needed. Thirdly, EV71 is found to evolve quickly in the past 15 years. Prospective cohort studies are warranted to clarify clinical and epidemiological significances of the antigenic and genetic variations between different EV71 genogroups, which is critical for vaccine design.

The microbiology of human hygiene and its impact on type 1 diabetes

The incidence of type 1 diabetes (T1D), as with several other autoimmune diseases and conditions, began to notably rise in the latter half of the last century. Most cases of T1D are not solely attributable to genetics and therefore, environmental influences are proposed to account for the difference. Humans live today in general under much more hygienic conditions than their ancestors. Although human enteroviruses (HEV) have been strongly implicated as causative environmental agents of T1D, recent work has shown that the bacterial genera in the gut of diabetics compared with non-diabetics, can vary significantly. Here, we consider these data in light of our non-hygienic human past in order to discuss a possible relationship between the resident bacterial biome and acute infectious events by HEV, suggesting how this may have influenced T1D incidences in the past and the risk for developing T1D today.

[Possible method of eradication of poliomyelitis as an infection]

Problem of poliomyelitis eradication is examined in the review. After the eradication of wild poliovirus, vaccine poliomyelitis virus continues to circulate in the human population. In rare cases it can cause the development of the disease. The authors describe disadvantages of the use of oral and inactivated poliomyelitis vaccines and note that by using oral poliomyelitis vaccine and eradication only of wild poliovirus, eradication of poliomyelitis as an infection will not succeed. As one of the approaches to reach this goal the authors propose the use of various enterovirus interference. Use of live enterovirus vaccine is described and its advantages and disadvantages are examined.

[Use of the cultural variants of Coxsackie A viruses in virological practice]

Coxsackie A viruses belong to the enteroviruses, the isolation of which from infectious materials and further cultivation are possible only when laboratory animals are infected. The authors could adapt the strains of 17 of 23 serotypes of these viruses to RD cell culture. The strains of 8 serotypes were additionally adapted to Vero cell culture. The cultural variants of Coxsackle A viruses were used to prepare immune sera. The Bacterial and Viral Agents Enterprise, M. P. Chumakov Institute of Poliomyelitis and Virus Encephalitides, Russian Academy of Medical Sciences, has set up the production of bacterial and viral drugs based on the cultural variants of 5 Coxsackie A virus serotypes. The cultural variants of 14 Coxsackie A virus serotypes were used to carry out a virus neutralization test. Examination of more than 600 children from Moscow and the Moscow Region showed the wide circulation of individual Coxsackie A virus serotypes. It also demonstrated a drastic reduction in Coxsackie A-7 virus circulation in the past 50 years.

Immunogenicity of a truncated enterovirus 71 VP1 protein fused to a Newcastle disease virus nucleocapsid protein fragment in mice

Enterovirus 71 (EV71) is one of the viruses that cause hand, foot and mouth disease. Its viral capsid protein 1 (VP1), which contains many neutralization epitopes, is an ideal target for vaccine development. Recently, we reported the induction of a strong immune response in rabbits to a truncated VP1 fragment (Nt-VP1t) displayed on a recombinant Newcastle disease virus (NDV) capsid protein. Protective efficacy of this vaccine, however, can only be tested in mice, since all EV71 animal models thus far were developed in mouse systems. In this study, we evaluated the type of immune responses against the protein developed by adult BALB/c mice. Nt-VP1t protein induced high levels of VP1 IgG antibody production in mice. Purified VP1 antigen stimulated activation, proliferation and differentiation of splenocytes harvested from these mice. They also produced significant levels of IFN-γ, a Th1-related cytokine. Taken together, Nt-VP1t protein is a potent immunogen in adult mice and our findings provide the data needed for testing of its protective efficacy in mouse models of EV71 infections.

Human enterovirus infections in children at increased risk for type 1 diabetes: the Babydiet study

AIMS/HYPOTHESIS

The aim of this study was to examine human enteroviruses (HEVs) and other intestinal viruses derived from children who participated in the Babydiet intervention study and to analyse the findings according to the appearance of islet autoantibodies, dietary intervention, maternal type 1 diabetes and clinical symptoms.

METHODS

In the Babydiet study the influence of first gluten exposure (6 or 12 months) on the development of islet autoimmunity was investigated in 150 children with increased genetic and familial risk for type 1 diabetes. Blood and stool samples were collected at 3 monthly intervals until the age of 3 years and yearly thereafter. Infections and clinical symptoms were recorded daily for the first year. In the present study, 339 stool samples collected from 104 children during the first year of life were analysed for HEVs and a certain proportion of the samples were analysed for other intestinal viruses.

RESULTS

HEV was detected in 32 (9.4%) samples from 24 (23.1%) children. Altogether 13 serotypes were identified, with HEV-A species being the most common. Children with gastrointestinal symptoms had norovirus (3/11) and sapovirus (1/11) infections in addition to HEV (1/11). Of the 104 children, 22 developed islet autoantibodies. HEV infections were detected in 18% (4/22) and 24% (20/82) of islet-autoantibody-positive and -negative children, respectively (p = 0.5). The prevalence of HEV was similar in the gluten-exposed groups and in children from mothers with type 1 diabetes or from affected fathers and/or siblings (p = 1.0 and 0.6, respectively).

CONCLUSIONS/INTERPRETATION

No correlation was found between the presence of HEV in the first year of life and the development of islet autoantibodies. There was no association between HEV infections and dietary intervention, maternal diabetes or clinical symptoms.

Detection of enteroviruses in clinical samples of patients with aseptic meningitis by rapid antigen detection assay

INTRODUCTION

Human enteroviruses represent the most common etiological agents of aseptic meningitis. Rapid diagnosis of aseptic meningitis affects the management of patients.

OBJECTIVE

The aim of this work was to assess the efficacy of rapid antigen detection (RAD) assay for the confirmation of human enteroviruses in comparison to that of the conventional cell culture (CCC), and to identify the serotypes associated with aseptic meningitis cases in the Autonomous Province of Vojvodina.

METHODS

RAD assay was carried out using centrifugation of inoculated Vero, RD and HEp-2 cell cultures and indirect immunofluorescence with Pan-Enterovirus 2E11 reagent (Millipore-Chemicon). CCC was performed using the same type of cells and the same immunofluorescence reagent for enterovirus confirmation.

RESULTS

Out of 70 analyzed samples (29 cerebrospinal fluid specimens, 27 stool specimens, 9 rectal and 5 throat swabs), 36 (51.4%) were positive by immunofluorescence after CCC and 34 (48.6%) by the RAD assay. The sensitivity of RAD assay was 94.4% and specificity 100%. Detection time of enteroviruses by the RAD assay was 3 days, and by CCC varied from 3 to 13 days (mean time 6.1 days). Within 72 h from inoculation, a cytopathic effect (CPE) occurred in only 19 (47.5%) of 40 CPE positive samples. Serotyping revealed 11 types of enteroviruses: coxsackievirus A16, B3, B4, B5, and echovirus 2, 4, 6, 11, 13, 16 and 30.

CONCLUSION

The RAD assay was slightly less sensitive than CCC and significantly shortened the detection time of enteroviruses, so it may be useful in rapid diagnosis of enteroviral meningitis.

Pharmacological and biological antiviral therapeutics for cardiac coxsackievirus infections

Subtype B coxsackieviruses (CVB) represent the most commonly identified infectious agents associated with acute and chronic myocarditis, with CVB3 being the most common variant. Damage to the heart is induced both directly by virally mediated cell destruction and indirectly due to the immune and autoimmune processes reacting to virus infection. This review addresses antiviral therapeutics for cardiac coxsackievirus infections discovered over the last 25 years. One group represents pharmacologically active low molecular weight substances that inhibit virus uptake by binding to the virus capsid (e.g., pleconaril) or inactivate viral proteins (e.g., NO-metoprolol and ribavirin) or inhibit cellular proteins which are essential for viral replication (e.g., ubiquitination inhibitors). A second important group of substances are interferons. They have antiviral but also immunomodulating activities. The third and most recently discovered group includes biological and cellular therapeutics. Soluble receptor analogues (e.g., sCAR-Fc) bind to the virus capsid and block virus uptake. Small interfering RNAs, short hairpin RNAs and antisense oligonucleotides bind to and led to degradation of the viral RNA genome or cellular RNAs, thereby preventing their translation and viral replication. Most recently mesenchymal stem cell transplantation has been shown to possess antiviral activity in CVB3 infections. Taken together, a number of antiviral therapeutics has been developed for the treatment of myocardial CVB infection in recent years. In addition to low molecular weight inhibitors, biological therapeutics have become promising anti-viral agents.

[Generation of recombinant human antibodies for EV71 virus]

OBJECTIVE

To obtain recombinant human anti-EV71 antibodies from a EV71-associated hand-foot-and-mouth disease patient-derived antibody phage library.

METHODS

A combinatorial human scFv library to enterovirus 71 (EV71) virus was constructed using antibody genes harvested from the blood of EV71 virus patients. The library was panned and selected by using purified VP1 protein of EV71 virus with phage display. After that the specific antibody was converted to full human IgG antibody with recombinant baculovirus/insect cell system.

RESULTS

One unique human scFv antibody specific for EV71 virus VP1 protein was obtained by ELISA, IFA and analysis of the antibody DNA sequence. The specific anti-VP1 human scFv antibody was converted to full human IgG antibody with recombinant baculovirus/insect cell system. The full human IgG antibody was tested in vitro for EV71 virus neutralization, resulting in no neutralizing activity with EV71 A type and EV71 C4 subtype.

CONCLUSION

The obtained human anti-EV71 antibodies without neutralizing activity laid the foundation for diagnosis of human EV71-associated hand-foot-and-mouth disease.

[Expression of VP0 protein of enterovirus 71 in Escherichia coli and generation of the corresponding polyclonal antibodies in guinea pigs]

AIM

To obtain recombinant VP0 protein of enterovirus 71, and generate the corresponding VP0-specific polyclonal antibodies, for molecular detection and characterization of EV71.

METHODS

The VP0 gene was amplified by PCR and cloned into vector pET26b to make pET-VP0 for the prokaryotic expression of VP0. The recombinant VP0 protein was expressed in E.coli BL21 harboring pET-VP0, purified from inclusion bodies, renatured, and subsequently used to immunize guinea pigs. The resultant antisera were evaluated for anti-VP0 titer, binding capacity and specificity by ELISA, immunofluorescence staining and Western blot assays.

RESULTS

Recombinant protein VP0 was efficiently produced in E.coli. Immunization of guinea pigs with recombinant VP0 elicited high-titer (1:10(6)) VP0-specific antibodies. Western blot analysis showed the resultant anti-VP0 sera reacted with E.coli-expressed VP0 as well as EV71 propagated in Vero cells. Moreover, the antisera positively recognized EV71 infected cells by immunofluorescence staining.

CONCLUSION

The recombinant VP0 and the corresponding polyclonal antibodies can be used to identify and characterize EV71, and therefore represent useful agents and tools for the development of new diagnostic methods and vaccines for EV71.

[Evaluation of the efficiency and reactogenicity of emulsion-based adjuvant systems in the manufacture of polyclonal enteroviral diagnostic sera]

Whether various adjuvants might be used in the manufacture of commercial enteroviral diagnostic sera (EDS) was studied. The following adjuvants: Ribi, SAF-1, and TiterMax were compared; vaseline-lanoline emulsion used to prepare EDSs, as well as modified Freund's complete adjuvant served as controls. Chinchilla rabbits were intramuscularly injected enterovirus antigens (enterovirus 70 and ECHO 2) together with the adjuvant emulsions. TiterMax showed the highest efficiency comparable with the activity of Freund's adjuvant. The activities of Ribi, SAF-1, and vaseline-lanoline emulsion were 3-4 times lower. The neutralizing activity of the sera obtained after 2-3 (TiterMax) or 4-5 (Ribi, SAF-1) immunizations was maximal. Further immunizations resulted in a reduction in the titers of neutralizing antibodies. TiterMax and vaseline-lanoline emulsion caused minimal complications at the site of inoculation whereas SAF-1 and Ribi gave rise to severer inflammatory responses.

Etiology of measles suspect cases reported in 2006-2007 in Poland

To achieve measles elimination, an efficient surveillance system for rash illnesses is necessary. The aim of the present study was to ascertain which viruses, other than measles, are causing measles-like illnesses (MLIs) in Poland. Serum samples (n=278) collected from MLI cases and submitted to the National Reference Laboratory during 2006-2007 were investigated for anti-measles (MeV), rubella (RUBV), parvovirus B19 (B19V), Epstein-Barr (EBV) and herpesvirus type-6 (HHV-6) IgM presence. Age was strongly associated with MLIs etiology. In the youngest age group, 0-4 years, MeV and HHV-6 infection were prevailing, while in group of 5-9 years--RUBV and B 19V. Measles was confirmed more often in patients with high fever (p < 0.001) and with rash lasting longer than 5 days (p < 0.001). The type of rash was not significantly associated with MeV infection. Our results strongly suggest that according to WHO EURO strategic plan, Poland is close to elimination phase. High number of MLIs were caused by pathogens other than measles. Addition of anti-B 19V IgM testing to routine MLIs screening protocol may improve system performance in the more advanced stages of measles elimination.

[Enterovirus infection as a risk factor of acute coronary syndrome and its complications]

Antigens of enteroviruses were detected quantitatively in the modified complement-binding reaction in blood samples from 102 of the 208 (49%) patients with ACS, in coronary artery tissues from 23 of 24 and heart from 51 of 94 (54.3%) patients with MI who died from cardiogenic shock and/or cardiac rupture. The relative level of enterovirus antigen (RLEVA) in the blood of patients with MI complicated and uncomplicated by cardiogenic shock and/or cardiac rupture was 0.42 +/- 0.04 and 0.29 +/- 0.02 arbitrary units respectively (p = 0.032) compared with 0.21 +/- 0.07 in patients with unstable angina (UA) (p = 0.0001). RLEVA in patients with UA was significantly lower than in those with uncomplicated MI (p < 0.011). RLEVA in necrotized myocardial areas after death from cardiogenic shock (0.54 +/- 0.18) and/or cardiac rupture (0.46 +/- 0.15) was higher than outside MI zones (0.30 +/- 0.14 and 0.26 +/- 0.10 respectively) (p < 0.01). RLEVA in coronary vessels feeding the necrotic zones of patients with MI complicated by cardiogenic shock (0.44 +/- 0.18) was higher (p = 0.03) than in the vessel feeding tissues outside the MI zone (0.29 +/- 0.19). It is concluded that enterovirus infection is a factor of ACS; it is directly involved in its pathogenesis and promotes the development of cardiogenic shock and/or cardiac rupture.

Development of an IgM-capture ELISA for Coxsackievirus A16 infection

Diagnosis of Coxsackievirus A16 (CA16) infection in China relies mainly on reverse transcription-polymerase chain reaction (RT-PCR) that require expensive equipment and special trained personnel, thus making its wide application in health care settings unlikely. In this study, a novel IgM anti-CA16 assay was developed for the detection of IgM antibodies to CA16 in serum. The responses and diagnostic value of IgM for the CA16 infection were assessed by testing 1970 serum samples. The results showed that sensitivity of IgM test was 84.6% (259/306, 95% CI: 80.1-88.5), and specificity in control subjects and patients with CA16 HFMD was 99.2% (1508/1520, 95% CI: 98.6-99.6) and 90.3% (14/144, 95% CI: 84.2-94.6), respectively. The IgM positive rate reached 56.3% in the sera collected within the first day after onset, increased continuously to 95.3% at day 5 to day 7 after onset, and then reached 100% after more than 8 days. The cross-reaction rate in patients infected with other non-CA16 enteroviruses was 9.7% (14/144). These results suggest that the IgM anti-CA16 assay offers a rapid, convenient, and reliable method to detect acute CA16 infections.

Dynamic change of mother-source neutralizing antibodies against enterovirus 71 and coxsackievirus A16 in infants

BACKGROUND

Enterovirus 71 (EV71) and coxsackievirus A16 (Cox A16) are major causative agents for hand, foot and mouth disease (HFMD). Studies indicate that the frequent HFMD outbreaks result in a few hundreds children's death in China in recent years. The vaccine and other research for HFMD need to be developed urgently.

THE AIMS OF OUR STUDY WERE

to explore dynamic development of mother-source neutralizing antibodies against EV71 and Cox A16 in infants from Jiangsu Province, China, and to provide the fundamental data for further establishing of corresponding immunization course.

METHODS

Peripheral blood samples were collected from 133 of parturient women once immediately before delivery and their infants at two and seven months of age. Method of micro-dose cytopathogenic effect was used to measure neutralizing antibodies against EV71 and Cox A16, respectively.

RESULTS

Seropositive rates of anti-EV71 and anti-Cox A16 in prenatal women were 79.7% (106/133) and 92.5% (123/133), respectively; geometric mean titers (GMTs) were 29.0 and 61.9; 75.9% (101/133) prenatal women were both positive in anti-EV71 and anti-Cox A16; seropositive rates of anti-EV71 and anti-Cox A16 were 25.6% (34/133) and 38.3% (51/133) in infants at two months of age; GMTs were 12.3 and 18.0, respectively. GMTs of anti-EV71 were significantly higher for infants at seven months (82.6) compared with that at two months (P < 0.05), showing infants had inapparently infected by EV71 during two to seven months. Although only one offspring (0.75%) at seven months was found having anti-Cox A16 transfered from maternal, this observation suggested no maternal antibody may remain in infants at seven months.

CONCLUSIONS

The prevalence of EV71 and Cox A16 were relatively high in Jiangsu Province. Bivalent vaccine against both EV71 and Cox A16 should be developed, and the ideal time point for prime immunization for infants is around 2-5 months of age.

Broad reactive monoclonal antibodies for rapid identification of enteroviruses show cross-reactivity with chikungunya virus infected cells

In the past decade, enterovirus 71 (EV71) and chikungunya (CHIK) virus have re-emerged periodically causing serious public health problems in Malaysia, since their first emergence in 1997 and 1998 respectively. This study demonstrates that CHIK virus causes similar patterns of cytopathic effect in cultured Vero cells as some enteroviruses. They also show positive cross-reaction on direct immunofluorescence staining using monoclonal antibodies meant for typing enteroviruses. Without adequate clinical and epidemiological information for correlation, CHIK virus isolated from patients with acute febrile rash can be wrongly reported as untypeable enterovirus due to its cross-reactivity with commercial pan-enterovirus monoclonal antibodies. This is due to the diagnostic laboratory being unaware of such cross-reactions as it has not been reported previously. Final identification of the virus could be determined with specific antibodies or molecular typing using specific oligonucleotide primers for the CHIK virus.

[Analyze the antibody level of enterovirus 71 about children cases of hand-foot-mouse disease outbreak]

OBJECTIVE

To analyze the Enterovirus 71 infectious status about probably cases of hand-foot-mouse disease (HFMD).

METHODS

Collect the blood samples of HFDM children probably cases and test the IgG, IgM antibody by ELISA, analyzed the age and gender distribution.

RESULTS

We collected 159 blood samples of children probably cases who are 1 to 5 years old. The average EV71 IgG positive rate is 63.5%, which of IgM is 12.0%. The positive rate of EV71 IgG is decrease by aged. Male's EV71 IgM positive rate is higher than female's significantly.

CONCLUSION

The pathogen of this case of HFMD outbreak is EV71. Male's EV7l infectious and incidence are higher than female's. The result of this investigation could provide information to HFMD disease control.

Etiology and clinico-epidemiological profile of acute viral encephalitis in children of western Uttar Pradesh, India

OBJECTIVES

To study the etiology of viral encephalitis (VE) in the children of western Uttar Pradesh, India and to assess the clinico-epidemiological profile of these children in relation to VE.

METHODS

Both cerebrospinal fluid and serum samples were collected from pediatric patients suffering from encephalitis hospitalized at Jawaharlal Nehru Medical College, Aligarh from July 2004 to November 2006. Viral isolation was done on RD cells, HEp-2 cells, and Vero cells from the cerebrospinal fluid samples of children with suspected VE. A microneutralization test was performed for enterovirus 71. An enzyme immunoassay for IgM antibodies was performed for measles virus, mumps virus, varicella zoster virus, herpes simplex virus 1, and Japanese encephalitis virus.

RESULTS

Eighty-seven patients were enrolled in the study. The most common etiology of VE was enterovirus 71 (42.1%), followed by measles (21.1%), varicella zoster virus (15.8%), herpes simplex virus (10.5%), and mumps (10.5%). Japanese encephalitis virus was not found in any case. Enterovirus 71 infection caused significant morbidity in children; mortality occurred in 50%. A preponderance of cases occurred in December. In our study generalized convulsions along with altered sensorium were the significant findings in patients with VE.

CONCLUSIONS

Enterovirus 71, the major etiology of VE in our study, was associated with significant mortality and morbidity. Such studies should be conducted frequently to assess the role of emerging VE in different regions.

[Development a method of quantitative assay for enterovirus 71]

OBJECTIVE

To establish a quantitative assay for enterovirus 71, this can be used in detecting the virus content during vaccine development and production.

METHODS

We established the method of quantitative assay for EV71 by using double antibody sandwich ELISA. The sensitivity, accuracy,precision and specificity of the method were evaluated.

RESULTS

We developed an ELISA method to quantitative assay for EV71. The quantitation limit of the method is 0.23 microg/ml and the quantitation scope of the method is 7.32-0.23 microg/ml, the coefficient correlation is R2 = 0.9976; The method showed good accuracy, precision and specificity. The recovery is between 90%-110% and the variation coefficient is lower than 10%.

CONCLUSION

An ELISA method was developed for the quantitative assay of EV71 virus, which can be used for the rapid quantitative determination of EV71 virus during vaccine development and production.

Molecular evaluation of enteroviruses in the pathogenesis of idiopathic dilated cardiomyopathy

BACKGROUND

There is great disparity in the literature as to the presence and relevance of enterovirus in heart tissue from patients with dilated cardiomyopathy (DCM). Published estimates of enteroviral positive tissue in DCM range from 0 to 50%. Very little sequence information is so far available on those samples which are positive.

HYPOTHESIS

Re-examination of fresh biopsy material from patients previously tested, plus 13 new cases of DCM, and sequencing the products would yield information on the validity of the technique and on the type of virus being detected.

METHODS

RNA from biopsy or explant tissue was tested for the presence of enterovirus using reverse transcriptase polymerase chain reaction (PCR). The nucleotide sequences of all positive PCR products were determined by direct sequencing.

RESULTS

Positive PCR signals were found in 10% of samples from patients with DCM and in 16% of control tissues. Two DCM and 12 control samples gave the same nucleotide sequence, which was different from the CB3 used as a positive control. The other 4 DCM samples all produced multiple bands on sequencing.

CONCLUSION

The results do not support a major role for enterovirus in DCM. There is need for some caution, however, as a review of the literature shows that studies using single biopsies, such as this one, produce consistently lower estimates for enterovirus than do those wherein multiple biopsies are examined.

[Preparation and identification of the monoclonal antibodies against VP1 capsid protein of Enterovius 71]

OBJECTIVE

To prepare monoclonal antibodies (McAbs) against VP1 capsid protein of Enterovirus 71.

METHODS

Two peptides, SP55 and SP70, containing amino acid 163-177 and 208-222 of VP1, were synthesized respectively. Immunized BALB/c mice with the synthetic peptides to establish the hybridoma cell strains secreting specific McAb to VP1. After the specific McAbs were prepared, identified and analyzed the titer by indirect ELISA assay. The positive clones were selected and their neutralization titer were determined by neutralization test.

RESULTS

Two high titered anti-VP1 antibodies secreted by the hybridoma cells showed good neutralization reaction with enterovirus 71 on RD cells, and the neutralization titer were 1:8 and 1:16 respectively.

CONCLUSION

Two high titered anti-VP1 antibodies, with good neutralization activity, secreted by the hybridoma cells, which lays the foundation for further study.

[Cytotoxic properties of diagnostic rabbit sera to enteroviruses specific features and localization]

Hyperimmune rabbit enterovirus-neutralizing diagnostic sera have a pronounced cytotoxic effect on the test tissue culture RD, HEp-2, and Vero cells and primary renal cells from African green monkeys (Cercopithecus aethiops). The specific features of this developing toxic effect, such as reduced proliferative activity and partial cytolysis, were revealed. The time course of changes in the generation of serum cytotoxicity during an immune response to repeated antigenic stimulation of donor animals is described. There is experimental evidence for no association of serum toxicity with specific neutralizing antibodies and with antibodies to cell culture antigens. Affinity chromatography is one of the possible techniques for purification of cytotoxic sera.

[Expression of recombinant VP1 protein of enterovirus 71 and development of serological assay for detection of EV71 infection]

OBJECTIVE

To obtain a recombinant purified Enterovirus 71 VPI protein and establishment of an early, rapid and accurate serological ELISA (enzyme-linked immunosorbent assay) for detection of EV71 infection.

METHODS

VP1 gene was amplified by PCR and clonel into pET-21b (+) vector, the positive recombinant plasmid were transformed into E. coli BI21(DE3), and was induced with IPTG, the recombinant protein by SDS-PAGE and Western Blot assays. Finally, the recombinant purified VP1 protein was used as a coated antigen for detection of serum anti-IgM and IgG against EV71 by ELISA.

RESULTS

The purified VP1 was obtained, and it can be recognized by sera of patients with EV71 infection associated with hand-foot-mouth disease. The A values of anti-EV71 IgM and IgG were significantly elevated as compared to healthy objects and HFMD patients without EV71 infection (P < 0.05). The sensitivity and specificity of IgM to EV71 were 73% and 77% compared with the RT-PCR results, respectively;and those of IgG being 82% and 83%, respectively.

CONCLUSIONS

The recombinant protein VP1 was produced and purified, and it was proved to have a good antigenicity and could be used to develop a serological diagnosis kit for EV71 infection in the future.

Analysis of pancreas tissue in a child positive for islet cell antibodies

AIMS/HYPOTHESIS

Type 1 diabetes is caused by an immune-mediated process, reflected by the appearance of autoantibodies against pancreatic islets in the peripheral circulation. Detection of multiple autoantibodies predicts the development of diabetes, while positivity for a single autoantibody is a poor prognostic marker. The present study assesses whether positivity for a single autoantibody correlates with pathological changes in the pancreas.

METHODS

We studied post mortem pancreatic tissue of a child who repeatedly tested positive for islet cell antibodies (ICA) in serial measurements. Paraffin sections were stained with antibodies specific for insulin, glucagon, somatostatin, interferon alpha, CD3, CD68, cyclooxygenase-2 (COX-2), beta-2-microglobulin, coxsackie B and adenovirus receptor (CAR), natural killer and dendritic cells. Apoptosis was detected using Fas-specific antibody and TUNEL assay. Enterovirus was searched for using immunohistochemistry and in situ hybridisation, as well as enterovirus-specific RT-PCR from serum samples.

RESULTS

The structure of the pancreas did not differ from normal. The number of beta cells was not reduced and no signs of insulitis were observed. Beta-2-microglobulin and CAR were strongly produced in the islets, but not in the exocrine pancreas. Enterovirus protein was detected selectively in the islets by two enterovirus-specific antibodies, but viral RNA was not found.

CONCLUSIONS/INTERPRETATION

These observations suggest that positivity for ICA alone, even when lasting for more than 1 year, is not associated with inflammatory changes in the islets. However, it is most likely that the pancreatic islets were infected by an enterovirus in this child.

[Adverse immunologic effects of immunomodulators revealed in experiment and ways to their surmounting]

Immunomodulators licopid (synthetic analogue of muramylpeptide) and purified staphylococcal toxoid (PST) in some variants of experiments on mice caused adverse immunologic effects: enhancement of virus-induced immunosupression, shift from latent immunosupression (revealed only by low, but not standard, doses of test-antigen) to manifested one. Described adverse effects are not a contraindication for use of the studied drugs in practice. Their adverse effects were revealed only after single inoculation, whereas in clinical conditions PST and licopid are used by courses with duration of 5-7 and 10 days respectively. Our experiments show that inoculation of suppressive doses of the preparations repeated by 2-4 times can prevent the shift from latent to manifested immunosupression. Enhancement of immunosupression was not observed in case of combined administration of suppressive doses of PST and adjuvant dose of licopid.

Virus antibody levels in IgA deficiency

IgA-deficient blood donors and their age- and sex-matched controls were compared for the occurrence of complement-fixing antibodies in serum against several viruses. The level in the IgA-deficient persons was slightly higher against several respiratory pathogens (adenoviruses, type B influenza virus, parainfluenza virus, and respiratory syncytial virus) that give rise to localized infections, and against coxsackie B group of viruses. No corresponding difference was observed in mumps, varicella, and cytomegalovirus infections, where viraemia is a characteristic feature, or in Mycoplasma pneumoniae infection.

[Laboratory testing of specimens from patients with viral encephalitis from some regions of China]

OBJECTIVE

To understand the viral etiology of viral encephalitis in China by detecting IgM antibody and viral RNA in the clinical samples of patients from some provinces of China by enzyme-linked immunosorbent assay and polymerase chain reaction.

METHOD

Serum and cerebrospinal fluid samples of 771 patients with viral encephalitis or meningitis were collected from six provinces of China and were stored at -20 degrees C or -70 degrees C. Enzyme-linked immunosorbent assays were used for detection of IgM antibody to Japanese encephalitis virus, coxsackievirus, echovirus, herpes simplex virus, measles virus, varicella-zoster virus, mumps virus, cytomegalovirus and Epstein-Barr virus. Polymerase chain reaction was applied for the detection of viral RNA of enteroviruses and seadornavirus.

RESULTS

IgM antibody was detected in 567 of 771 (73.5%) cases. The most common pathogen was Japanese encephalitis virus (47.0%, 362/771), followed by mumps virus (10.6%, 82/771), enteroviruses (8.8%, 68/771), herpes simplex virus (5.7%, 44/771), measles virus (0.4%, 3/771), varicella-zoster virus (0.4%, 3/771), Epstein-Barr virus (0.4%, 3/771), and cytomegalovirus (0.3%, 2/771). Enterovirus was positive in 8 cases, seadornavirus was negative in all the cases by PCR.

CONCLUSION

According to the study, Japanese encephalitis was the most important encephalitis in China. Mumps virus was another important pathogen. Enteroviruses and herpes simplex virus were also important pathogens.