Molecular characterization of virus-induced autoantibody responses

Profiling the specificity of clonally expanded plasma cells during chronic viral infection by single-cell analysis

Plasma cells and their secreted antibodies play a central role in the long-term protection against chronic viral infection. However, due to experimental limitations, a comprehensive description of linked genotypic, phenotypic, and antibody repertoire features of plasma cells (gene expression, clonal frequency, virus specificity, and affinity) has been challenging to obtain. To address this, we performed single-cell transcriptome and antibody repertoire sequencing of the murine BM plasma cell population following chronic lymphocytic choriomeningitis virus infection. Our single-cell sequencing approach recovered full-length and paired heavy- and light-chain sequence information for thousands of plasma cells and enabled us to perform recombinant antibody expression and specificity screening. Antibody repertoire analysis revealed that, relative to protein immunization, chronic infection led to increased levels of clonal expansion, class-switching, and somatic variants. Furthermore, antibodies from the highly expanded and class-switched (IgG) plasma cells were found to be specific for multiple viral antigens and a subset of clones exhibited cross-reactivity to nonviral and autoantigens. Integrating single-cell transcriptome data with antibody specificity suggested that plasma cell transcriptional phenotype was correlated to viral antigen specificity. Our findings demonstrate that chronic viral infection can induce and sustain plasma cell clonal expansion, combined with significant somatic hypermutation, and can generate cross-reactive antibodies.

Impact of SARS-CoV-2 infection on the recovery of peripheral blood mononuclear cells by density gradient

SARS-CoV-2 virus infection is responsible for coronavirus disease (COVID-19), which is characterised by a hyperinflammatory response that plays a major role in determining the respiratory and immune-mediated complications of this condition. While isolating peripheral blood mononuclear cells (PBMCs) from whole blood of COVID-19 patients by density gradient centrifugation, we noticed some changes in the floating properties and in the sedimentation of the cells on density medium. Investigating this further, we found that in early phase COVID-19 patients, characterised by reduced circulating lymphocytes and monocytes, the PBMC fraction contained surprisingly high levels of neutrophils. Furthermore, the neutrophil population exhibited alterations in the cell size and in the internal complexity, consistent with the presence of low density neutrophils (LDNs) and immature forms, which may explain the shift seen in the floating abilities and that may be predictive of the severity of the disease. The percentage of this subset of neutrophils found in the PBMC band was rather spread (35.4 ± 27.2%, with a median 28.8% and IQR 11.6-56.1, Welch's t-test early phase COVID-19 versus blood donor healthy controls P < 0.0001). Results confirm the presence of an increased number of LDNs in patients with early stage COVID-19, which correlates with disease severity and may be recovered by centrifugation on a density gradient together with PBMCs.

Using bioinformatic protein sequence similarity to investigate if SARS CoV-2 infection could cause an ocular autoimmune inflammatory reactions?

Although severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) infection have emerged globally, findings related to ocular involvement and reported cases are quite limited. Immune reactions against viral infections are closely related to viral and host proteins sequence similarity. Molecular Mimicry has been described for many different viruses; sequence similarities of viral and human tissue proteins may trigger autoimmune reactions after viral infections due to similarities between viral and human structures. With this study, we aimed to investigate the protein sequence similarity of SARS CoV-2 with retinal proteins and retinal pigment epithelium (RPE) surface proteins. Retinal proteins involved in autoimmune retinopathy and retinal pigment epithelium surface transport proteins were analyzed in order to infer their structural similarity to surface glycoprotein (S), nucleocapsid phosphoprotein (N), membrane glycoprotein (M), envelope protein (E), ORF1ab polyprotein (orf1ab) proteins of SARS CoV-2. Protein similarity comparisons, 3D protein structure prediction, T cell epitopes-MHC binding prediction, B cell epitopes-MHC binding prediction and the evaluation of the antigenicity of peptides assessments were performed. The protein sequence analysis was made using the Pairwise Sequence Alignment and the LALIGN program. 3D protein structure estimates were made using Swiss Model with default settings and analyzed with TM-align web server. T-cell epitope identification was performed using the Immune Epitope Database and Analysis (IEDB) resource Tepitool. B cell epitopes based on sequence characteristics of the antigen was performed using amino acid scales and HMMs with the BepiPred 2.0 web server. The predicted peptides/epitopes in terms of antigenicity were examined using the default settings with the VaxiJen v2.0 server. Analyses showed that, there is a meaningful similarities between 6 retinal pigment epithelium surface transport proteins (MRP-4, MRP-5, RFC1, SNAT7, TAUT and MATE) and the SARS CoV-2 E protein. Immunoreactive epitopic sites of these proteins which are similar to protein E epitope can create an immune stimulation on T cytotoxic and T helper cells and 6 of these 9 epitopic sites are also vaxiJen. These result imply that autoimmune cross-reaction is likely between the studied RPE proteins and SARS CoV-2 E protein. The structure of SARS CoV-2, its proteins and immunologic reactions against these proteins remain largely unknown. Understanding the structure of SARS CoV-2 proteins and demonstration of similarity with human proteins are crucial to predict an autoimmune response associated with immunity against host proteins and its clinical manifestations as well as possible adverse effects of vaccination.

CXCR5+PD-1+ follicular helper CD8 T cells control B cell tolerance

Many autoimmune diseases are characterized by the production of autoantibodies. The current view is that CD4⁺ T follicular helper (Tfh) cells are the main subset regulating autoreactive B cells. Here we report a CXCR5⁺PD1⁺ Tfh subset of CD8⁺ T cells whose development and function are negatively modulated by Stat5. These CD8⁺ Tfh cells regulate the germinal center B cell response and control autoantibody production, as deficiency of Stat5 in CD8 T cells leads to an increase of CD8⁺ Tfh cells, resulting in the breakdown of B cell tolerance and concomitant autoantibody production. CD8⁺ Tfh cells share similar gene signatures with CD4⁺ Tfh, and require CD40L/CD40 and TCR/MHCI interactions to deliver help to B cells. Our study thus highlights the diversity of follicular T cell subsets that contribute to the breakdown of B-cell tolerance.

B cell response and antibody production are generally facilitated by CD4⁺ follicular helper (Tfh) cells. Here the authors identify a subset of CXCR5⁺PD1⁺CD8⁺ Tfh cells that is normally suppressed by STAT5 signaling, so that STAT5 deficiency in mice increases the number of these CD8⁺ Tfh cells and induces concomitant production of autoantibodies.

Attaining threshold antibody cytotoxicity for selective tumor cell destruction: an opinion article

We propose a novel immunotherapeutic paradigm that justifies application of several antibodies to various membrane-associated antigens to achieve a critical threshold density of immune complexes on the surface of cancer cells sufficient for triggering downstream cytolytic pathways. Indeed, some cancer-associated antigens (such as cancer/testis antigens) were found to be expressed on many cancer (but not normal) cells, with their baseline membrane expression levels being originally quite low for some of them, or even further down-regulated due to immune-driven cell selection. To achieve the mandatory threshold density of membrane-associated immune complexes on malignant cells, the concept stipulates combined application of antibodies specific for a cancer-associated antigen along with antibodies against an antigen expressed not only on tumor, but also on normal cells. In the proposed scenario it is of vital importance that the latter antibodies should be applied in suboptimal dosage to exclude the destruction of normal cells devoid of a cancer-associated antigen. Malignant cells often co-express antigens not present concurrently on normal cells at high levels. In such cases, suboptimal dosages of antibodies specific for those antigens could also be applied to achieve cumulative effect leading to selective destruction of tumour cells. Hence, the described immunotherapeutic technology could be used metaphorically speaking as a kind of ‘immunological knife’, which is capable of highly selective destruction of cancer cells without destroying normal cells.

ANA testing in the presence of acute and chronic infections

Autoantibody testing is performed to help diagnose patients who have clinical symptoms suggestive of possible autoimmune diseases. Antinuclear antibodies (ANA) are present in many systemic autoimmune conditions such as systemic lupus erythematosus (SLE). However, a positive ANA test may also be seen with non-autoimmune inflammatory diseases, including both acute and chronic infections. When the ANA test is used as an initial screen in patients with non-specific clinical symptoms, such as fever, joint pain, myalgias, fatigue, rash, or anemia, the likelihood of a positive result due to infection will increase, especially in children. This article identifies acute and chronic infectious diseases that are likely to produce a positive ANA result and summarizes recent literature addressing both the causes and consequences of these findings.

Emerging blood-based biomarkers for detection of gastric cancer

Early detection and efficient monitoring of tumor dynamics are prerequisites for reducing disease burden and mortality, and for improving the management of patients with gastric cancer (GC). Blood-based biomarker assays for the detection of early-stage GC could be of great relevance both for population-wide or risk group-based screening programs, while circulating biomarkers that reflect the genetic make-up and dynamics of the tumor would allow monitoring of treatment efficacy, predict recurrences and assess the genetic heterogeneity of the tumor. Recent research to identify blood-based biomarkers of GC has resulted in the identification of a wide variety of cancer-associated molecules, including various proteins, autoantibodies against tumor associated antigens, cell-free DNA fragments, mRNAs and various non-coding RNAs, circulating tumor cells and cancer-derived extracellular vesicles. Each type of these biomarkers provides different information on the disease status, has different advantages and disadvantages, and distinct clinical usefulness. In the current review, we summarize the recent developments in blood-based GC biomarker discovery, discuss the origin of various types of biomarkers and their clinical usefulness and the technological challenges in the development of biomarker assays for clinical use.

Evolution of the Humoral Response during HCV Infection: Theories on the Origin of Broadly Neutralizing Antibodies and Implications for Vaccine Design

Similar to human immunodeficiency virus (HIV)-1, vaccine-induced elicitation of broadly neutralizing (bNt) antibodies (Abs) is gaining traction as a key goal toward the eradication of the hepatitis C virus (HCV) pandemic. Previously, the significance of the Ab response against HCV was underappreciated given the prevailing evidence advancing the role of the cellular immune response in clearance and overall control of the infection. However, recent findings have driven growing interest in the humoral arm of the immune response and in particular the role of bNt responses due to their ability to confer protective immunity upon passive transfer in animal models. Nevertheless, the origin and development of bNt Abs is poorly understood and their occurrence is rare as well as delayed with emergence only observed in the chronic phase of infection. In this review, we characterize the interplay between the host immune response and HCV as it progresses from the acute to chronic phase of infection. In addition, we place these events in the context of current hypotheses on the origin of bNt Abs against the HIV-1, whose humoral immune response is better characterized. Based on the increasing significance of the humoral immune response against HCV, characterization of these events may be critical in understanding the development of the bNt responses and, thus, provide strategies toward effective vaccine design.

Serological markers of autoimmunity in children with hepatitis A: relation to acute and fulminant presentation

OBJECTIVES

Hepatitis A virus (HAV) infection tends to be a self-limiting disease without serious sequelae, but fulminant hepatitis, with a high mortality, develops in 0.1-0.2% of the cases. Sometimes, HAV infection precipitates autoimmune hepatitis (AIH). We aimed to assess the frequency and clinical significance of serologic markers of autoimmunity during hepatitis A infection with an acute or fulminant presentation compared with those in AIH.

METHODS

The study included 126 children: 46 with HAV infection (33 with acute and 13 with fulminant presentation), 53 with AIH, and 27 healthy controls. In all, we measured autoantibodies titer (antinuclear antibody, antismooth muscle antibody, and liver kidney microsomal antibody-1) and serum gammaglobulins.

RESULTS

Autoantibodies were detected in the majority of HAV (63.1%) and AIH (79.2%) groups, but in none of the controls. Gammaglobulins were significantly higher in the HAV group (1.93±0.57 g/dl) than in the controls (1.32±0.29 g/dl), but lower than that in the AIH group (2.93±1.2 g/dl) (P<0.0001 for all). In the HAV group, gammaglobulins were significantly higher in those with fulminant (2.21±0.46 g/dl) than in those with acute presentation (1.82±0.57 g/dl) (P=0.019), but comparable with that in AIH (P=0.095). Gammaglobulins correlated significantly with disease severity in both HAV and AIH groups.

CONCLUSION

Hypergammaglobulinemia and a high occurrence of autoantibodies are encountered in HAV infection. This may support the immunological basis of its pathogenesis. Moreover, the higher gammaglobulins in fulminant HAV, with an insignificant difference from that in AIH, suggest that a more aggressive immunological reaction is related to this presentation.

Specificity, polyspecificity, and heterospecificity of antibody-antigen recognition

The concept of antibody specificity is analyzed and shown to reside in the ability of an antibody to discriminate between two antigens. Initially, antibody specificity was attributed to sequence differences in complementarity determining regions (CDRs), but as increasing numbers of crystallographic antibody-antigen complexes were elucidated, specificity was analyzed in terms of six antigen-binding regions (ABRs) that only roughly correspond to CDRs. It was found that each ABR differs significantly in its amino acid composition and tends to bind different types of amino acids at the surface of proteins. In spite of these differences, the combined preference of the six ABRs does not allow epitopes to be distinguished from the rest of the protein surface. These findings explain the poor success of past and newly proposed methods for predicting protein epitopes. Antibody polyspecificity refers to the ability of one antibody to bind a large variety of epitopes in different antigens, and this property explains how the immune system develops an antibody repertoire that is able to recognize every antigen the system is likely to encounter. Antibody heterospecificity arises when an antibody reacts better with another antigen than with the one used to raise the antibody. As a result, an antibody may sometimes appear to have been elicited by an antigen with which it is unable to react. The implications of antibody polyspecificity and heterospecificity in vaccine development are pointed out.

Influenza virus infection elicits protective antibodies and T cells specific for host cell antigens also expressed as tumor-associated antigens: a new view of cancer immunosurveillance

Most tumor-associated antigens (TAA) are self-molecules that are abnormally expressed in cancer cells and become targets of antitumor immune responses. Antibodies and T cells specific for some TAAs have been found in healthy individuals and are associated with lowered lifetime risk for developing cancer. Lower risk for cancer has also been associated with a history of febrile viral diseases. We hypothesized that virus infections could lead to transient expression of abnormal forms of self-molecules, some of which are TAAs; facilitated by the adjuvant effects of infection and inflammation, these molecules could elicit specific antibodies, T cells, and lasting immune memory simultaneously with immunity against viral antigens. Such infection-induced immune memory for TAA would be expected to provide life-long immune surveillance of cancer. Using influenza virus infection in mice as a model system, we tested this hypothesis and demonstrated that influenza-experienced mice control 3LL mouse lung tumor challenge better than infection-naive control mice. Using 2D-difference gel electrophoresis and mass spectrometry, we identified numerous molecules, some of which are known TAAs, on the 3LL tumor cells recognized by antibodies elicited by two successive influenza infections. We studied in detail immune responses against glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone H4, HSP90, malate dehydrogenase 2, and annexin A2, all of which were overexpressed in influenza-infected lungs and in tumor cells. Finally, we show that immune responses generated through vaccination against peptides derived from these antigens correlated with improved tumor control.

Autism spectrum disorder in children born preterm-role of exposure to perinatal inflammation

Autism Spectrum Disorder (ASD) is the collective term for neurodevelopmental disorders characterized by qualitative impairments in social interaction, communication, and a restricted range of activities and interests. Many countries, including Australia, have reported a dramatic increase in the number of diagnoses over the past three decades, with current prevalence of ASD at 1 in every 110 individuals (~1%). The potential role for an immune-mediated mechanism in ASD has been implicated by several studies, and some evidence suggests a potential link between prenatal infection-driven inflammation and subsequent development of ASD. Furthermore, a modest number of contemporary studies have reported a markedly increased prevalence of ASD in children born preterm, who are at highest risk of exposure to perinatal inflammation. However, the mechanisms that underpin the susceptibility to infection-driven inflammation during pregnancy and risk of preterm birth, and how these intersect with the subsequent development of ASD in the offspring, is not understood. This review aims to summarize and discuss the potential mechanisms and evidence for the role of prenatal infection on the central nervous system, and how it may increase the susceptibility for ASD pathogenesis in children born preterm.

Polyreactive antibodies in adaptive immune responses to viruses

B cells express immunoglobulins on their surface where they serve as antigen receptors. When secreted as antibodies, the same molecules are key elements of the humoral immune response against pathogens such as viruses. Although most antibodies are restricted to binding a specific antigen, some are polyreactive and have the ability to bind to several different ligands, usually with low affinity. Highly polyreactive antibodies are removed from the repertoire during B-cell development by physiologic tolerance mechanisms including deletion and receptor editing. However, a low level of antibody polyreactivity is tolerated and can confer additional binding properties to pathogen-specific antibodies. For example, high-affinity human antibodies to HIV are frequently polyreactive. Here we review the evidence suggesting that in the case of some pathogens like HIV, polyreactivity may confer a selective advantage to pathogen-specific antibodies.

Control of B cells expressing naturally occurring autoantibodies

Naturally occurring autoantibodies (NAbs) are typically polyreactive, bind with low affinity to a discrete set of autoantigens and are encoded by variable region genes in germline configuration. They differ from disease-associated autoantibodies (autoAb), which are mostly monoreactive, somatically mutated and of high affinities. Structure-function studies have shown that polyreactivity of NAbs relies on the somatically generated complementarity determining region, CDR3, of the heavy chain. This finding suggested that NAb-producing B cells were positively selected from the pre-immune B-cell repertoire. The biological significance of this selection remains, however, unclear. Data originating mainly from transgenic mice have shown that mature NAb-producing B cells are frequently ignorant toward their antigen, possibly due to their low affinity, though active tolerance mechanisms are not excluded. An important issue is whether NAb-producing B cells constitute the pool from which pathologic auto Ab emerge after autoantigen-driven maturation. We summarize results obtained in mouse models, showing that some infectious agents are able to induce an autoantigen-driven activation of certain NAb-producing B cells. However direct proof that selection by autoantigen may lead to somatic hypermutation are still lacking. Other data tend to suggest that pathologic auto Abs may derive from non-autoimmune B cells that have diversified by somatic hypermutation of their variable region genes.

Evolving concepts of specificity in immune reactions

Our goal is to provide a perspective on current understanding of the origins of specificity in immune reactions, a topic that has intrigued scientists for over a century. A fundamental property of adaptive immune responses is the ability to discriminate among an immense variety of substances by means of antibodies (Abs) and Ab-like receptors on T lymphocytes [T-cell receptors (TCRs)], each able to bind a particular chemical structure [the antigen (Ag)] and not, or only weakly, similar alternatives. Evidence has long existed, however, and has grown, especially recently, that while exhibiting remarkable specificity, many individual Abs and TCRs can also bind a variety of very different ligands. How can Ag recognition by these receptors exercise the great specificity for which they are renowned and yet react with a variety of different ligands (degeneracy)? We critically consider the mechanistic bases for this specificity/degeneracy enigma and also compare and contrast Ag recognition by Abs and TCRs.

The identification of a novel Paneth cell-associated antigen in a familial adenomatous polyposis mouse model

Wnt signaling is important for the differentiation of the Paneth cell lineage in the small intestine. However, abnormal Wnt signaling predisposes to intestinal tumorigenesis in the familial adenomatous polyposis (FAP) mouse model. Vaccination with dendritic cells fused with tumor cells from FAP mice, in which Wnt signaling is constitutively activated, induced humoral immunity and suppressed intestinal tumor development. We identified the novel antigen Apa1 (Adenomatous polyposis antigen 1) recognized by antibodies in vaccinated mouse serum. Apa1 was localized in the Paneth cell-like tumor cells showing cytoplasmic β-catenin accumulation and also in normal Paneth cells at the bottom of the crypts. Phospholipase A2 (Pla2g2a), known to act as an anti-bacterial agent and a major suppressor of intestinal tumors, was also expressed in the Paneth cells. These results suggest that Apa1 might be involved in anti-microbial defense and could influence tumor development in FAP mice via modulation of commensal microbiota.

A comprehensive analysis of filamentous phage display vectors for cytoplasmic proteins: an analysis with different fluorescent proteins

Filamentous phage display has been extensively used to select proteins with binding properties of specific interest. Although many different display platforms using filamentous phage have been described, no comprehensive comparison of their abilities to display similar proteins has been conducted. This is particularly important for the display of cytoplasmic proteins, which are often poorly displayed with standard filamentous phage vectors. In this article, we have analyzed the ability of filamentous phage to display a stable form of green fluorescent protein and modified variants in nine different display vectors, a number of which have been previously proposed as being suitable for cytoplasmic protein display. Correct folding and display were assessed by phagemid particle fluorescence, and with anti-GFP antibodies. The poor correlation between phagemid particle fluorescence and recognition of GFP by antibodies, indicates that proteins may fold correctly without being accessible for display. The best vector used a twin arginine transporter leader to transport the displayed protein to the periplasm, and a coil-coil arrangement to link the displayed protein to g3p. This vector was able to display less robust forms of GFP, including ones with inserted epitopes, as well as fluorescent proteins of the Azami green series. It was also functional in mock selection experiments.

Healthy individuals have T-cell and antibody responses to the tumor antigen cyclin B1 that when elicited in mice protect from cancer

We previously identified the aberrantly expressed cell cycle regulator cyclin B1 as a tumor antigen recognized by antibodies and T cells from patients with breast, lung, and head and neck cancers. Ordinarily expressed only transiently in the G2/M stage of the cell cycle in normal cells, cyclin B1 is constitutively expressed at high levels in the cytoplasm of these and many other tumor types, leading to its recognition by the cancer patient's immune system. We report here an unexpected observation that cyclin B1-specific antibody and memory CD4 and CD8 T cells are also found in many healthy individuals who have no history of cancer. Moreover, young as well as older healthy people have these responses suggesting that events other than cancer, which occur either early in life or throughout life, may lead to aberrant cyclin B1 expression and anti-cyclin B1 immunity. The role, if any, of immunity to this tumor-associated antigen is not known. We wanted to determine specifically whether immunity to cyclin B1 might be important in the immunosurveillance of cyclin B1+ tumors. We therefore tested in mice the effectiveness of vaccine-elicited anti-cyclin B1 immunity against a cyclin B1+ mouse tumor that was chosen based on our published observation that cyclin B1 overexpression is associated with the lack of p53 function. We found that cyclin B1 DNA prime-protein boost vaccine protected mice from a challenge with a tumor cell line that was established from a tumor arising in the p53(-/-) mouse that spontaneously overexpresses cyclin B1.

Molecular mapping of autoimmune B cell responses in experimental myocarditis

Autoimmune responses directed against heart-specific antigens most likely play a key role in the pathogenesis of myocarditis. Although autoantibodies against cardiac determinants are frequently detected both in human patients and mice suffering from myocarditis, the immunological mechanisms for their induction have not yet been fully explored. We used here the SEREX approach (serological identification of recombinantly expressed proteins) to molecularly dissect heart-specific autoimmune B cell responses that develop in the course of experimentally induced myocarditis. Screening of a heart cDNA library with sera of cardiac myosin heavy chain alpha (myhcalpha) peptide-immunized BALB/c mice revealed a strong focusing of the B cell response on the myhcalpha protein. The vast majority of the myhcalpha transcripts coded for regions other than the sequence of the immunogenic myhcalpha peptide, indicating extensive intramolecular epitope spreading. Importantly, we found that the infection with cardiotropic viruses such as MCMV and Coxsackievirus B3 elicited specific autoantibody pattern with a particular skewing to the myhcalpha protein. The induction of myhcalpha peptide-specific Th cells in the course of both infections suggests that infection-associated determinant spreading on the Th cell level paves the way for a focused and dominant anti-myhcalpha B cell response.

Dynamics and magnitude of virus-induced polyclonal B cell activation mediated by BCR-independent presentation of viral antigen

Hypergammaglobulinemia and production of autoantibodies occur during many viral infections, and studies have suggested that viral antigen-presenting B cells may become polyclonally activated by CD4 T cells in vivo in the absence of viral engagement of the BCR. However, we have reported that CD4 cells in lymphocytic choriomengitis virus (LCMV)-infected mice kill adoptively transferred B cells coated with LCMV class II peptides. We report here that most of the surviving naïve B cells presenting class II MHC peptides undergo an extensive differentiation process involving both proliferation and secretion of antibodies. Both events require CD4 cells and CD40/CD40L interactions but not MyD88-dependent signaling within the B cells. B cells taken from immunologically tolerant donor LCMV-carrier mice with high LCMV antigen load became activated following adoptive transfer into LCMV-infected hosts, suggesting that B cells present sufficient antigen for this process during a viral infection. No division or activation of B cells was detected at all in virus-infected hosts in the absence of cognate CD4 T cells and class II antigen. This approach, therefore, formally demonstrates and quantifies a virus-induced polyclonal proliferation and differentiation of B cells, which, due to their high proportion, would mostly have BCR not specific for the virus.

Cancer immunotherapy and preclinical studies: why we are not wasting our time with animal experiments

Experimental research on the immune response to transplanted tumors has led to pioneering discoveries that laid many of the foundations for the current field of immunology. Experimental research in oncology has proven that murine and human tumors have antigens that are truly cancer specific. This article discusses research investigating how can antigens on cancer cells be used to help eradicate cancer.

Rapid molecular dissection of viral and bacterial immunomes

The development of preventive or therapeutic recombinant vaccines and the generation of serodiagnostic assays for infectious diseases depend essentially on the availability of molecularly defined antigens. A major bottleneck for the identification of suitable target antigens for many pathogens is the isolation of sufficient amounts of material for subsequent genomic or proteomic screening. Applying a highly efficient expression cloning strategy to the human pathogens vaccinia virus (VV) and Chlamydia pneumoniae (CP), we demonstrate that sub-nanogram amounts of isolated nucleic acids can be utilized to determine comprehensive sets of immunodominant antigens. Remarkably, the approach not only confirmed the immunogenicity of previously reported antigens but also disclosed novel vaccine candidates conserved in orthopoxviruses, including antigenic envelope proteins and immunodominant CTL epitopes. Moreover, as illustrated for CP infection, we show that a panel of novel antigens can be readily selected from the initially discovered pool to build up pathogen-specific seroassays. The established approach is rapid, making it an attractive procedure for the comprehensive dissection of immunomes of known human pathogens and newly emerging infectious agents.

Consequence or coincidence? The occurrence, pathogenesis and significance of autoimmune manifestations after viral vaccines

BACKGROUND

Viruses and virus-induced lymphokines may have an important role in the pathogenesis of autoimmunity (Schattner A. Clin Immunol Immunopathol; 1994). The occurrence and significance of autoimmune manifestations after the administration of viral vaccines remain controversial.

METHODS

Medline search of all relevant publications from 1966 through June 2004 with special emphasis on search of each individual autoimmune manifestation and vaccination, as well as specifically searching each viral vaccine for all potential autoimmune syndromes reported. All relevant publications were retrieved and critically analyzed.

RESULTS

The most frequently reported autoimmune manifestations for the various vaccinations, were: hepatitis A virus (HAV)--none; hepatitis B virus (HBV)--rheumatoid arthritis, reactive arthritis, vasculitis, encephalitis, neuropathy, thrombocytopenia; measles, mumps and rubella vaccine (MMR)--acute arthritis or arthralgia, chronic arthritis, thrombocytopenia; influenza--Guillain-Barre syndrome (GBS), vasculitis; polio--GBS; varicella--mainly neurological syndromes. Even these 'frequent' associations relate to a relatively small number of patients. Whenever controlled studies of autoimmunity following viral vaccines were undertaken, no evidence of an association was found.

CONCLUSIONS

Very few patients may develop some autoimmune diseases following viral vaccination (in particular - arthropathy, vasculitis, neurological dysfunction and thrombocytopenia). For the overwhelming majority of people, vaccines are safe and no evidence linking viral vaccines with type 1 diabetes, multiple sclerosis (MS) or inflammatory bowel disease can be found.