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The aim of the work is to study the indicators of cellular and humoral immune response and FAN of patients with tonsillitis in children infected with HHV-6 type. Materials and methods of research. In 72 children aged 3--15 years (mean age 8.42 ± 1.44 years), patients with streptococcal tonsillitis of moderate severity, the levels of the main subpopulations of blood lymphocytes were determined using monoclonal antibodies by solid-phase enzyme-linked immunosorbent assay, phagocytic activity of neutrophils (FAN) using the nitrosine tetrazolium reduction test (HCT test) and serum Ig A, Ig M, Ig G levels by radial immunodiffusion. The studies were carried out in the acute period and in the period of convalescence. Mathematical and statistical processing of the data obtained was carried out using Microsoft Excel 2003 and Statistica 6.0 programs. The significance of differences between the mean values was determined using the Student's test (t). Results. Different mechanisms of formation of pathological process at streptococcal tonsillitis at children depending on the concomitant HHV-6 type infection are revealed. In patients with mixed infection in the acute period of tonsillitis determine the signs of deficiency of the cellular immune system with the maximum deviation of CD-lymphocytes (t = 3.13 vs. t = 2.16 in mono-infection), the tension in the humoral link of the immune response Ig deviation (t = 1.63 against t = 0.91 in mono-infection) on the background of phagocytosis violation in terms of FAN deviation (t = 3.22 against t = 2.01 in mono-infection). By the period of convalescence, the restoration of the imbalance of specific and non-specific protection factors does not occur. Increased Ig G content in the acute period is one of the features of streptococcal tonsillitis in children on the background of HHV-6t infection. Conclusions. Concomitant VGL-6 type infection in children with streptococcal tonsillitis affects the mechanisms of formation of the inflammatory process and the reactivity of patients, forming the preconditions for adverse outcomes of the disease. The obtained results can be the basis for early detection of herpes virus infection in patients with tonsillitis, will help to optimize the management of patients in different periods of the disease. [ABSTRACT FROM AUTHOR]

Marchuk's model of a general immune reaction is presented in the paper. The results of investigation of the model are summarized. The qualitative behaviour of solutions to the model and its simplification is described. Many illustrations of recovery process, oscillations or lethal outcomes of a disease are shown. The model with time-dependent immune reactivity is also considered. Periodic dynamics caused by different reasons are compared. In the last section adaptation of the model to tumour-immune interactions is proposed. The role of interleukins in immune processes is taken into account to adapt Marchuk's model to tumour growth dynamics. Possible immunotherapy is also considered in the proposed model. Some preliminary analysis of the model is presented. [ABSTRACT FROM AUTHOR]

Monocytes represent a class of immune cells that play a key role in the innate and adaptive immune response against infections. One mechanism employed by monocytes for sensing foreign antigens is via toll-like receptors (TLRs)--transmembrane proteins that distinguish classes of foreign pathogens, for example, bacteria (TLR4, 5, and 9) vs. fungi (TLR2) vs. viruses (TLR3, 7, and 8). Binding of antigens activates a signaling cascade through TLR receptors that culminate in secretion of inflammatory cytokines. Detection of these cytokines can provide valuable clinical data for drug developers and disease investigations, but this usually requires a large sample volume and can be technically inefficient with traditional techniques such as flow cytometry, enzyme-linked immunosorbent assay, or luminex. This paper describes an approach whereby antibody arrays for capturing cells and secreted cytokines are encapsulated within a microfluidic device that can be reconfigured to operate in serial or parallel mode. In serial mode, the device represents one long channel that may be perfused with a small volume of minimally processed blood. Once monocytes are captured onto antibody spots imprinted into the floor of the device, the straight channel is reconfigured to form nine individually perfusable chambers. To prove this concept, the microfluidic platform was used to capture monocytes from minimally processed human blood in serial mode and then to stimulate monocytes with different TLR agonists in parallel mode. Three cytokines, tumor necrosis factor-a, interleukin (IL)-6, and IL-10, were detected using anti-cytokine antibody arrays integrated into each of the six chambers. We foresee further use of this device in applications such as pediatric immunology or drug/vaccine testing where it is important to balance small sample volume with the need for high information content. [ABSTRACT FROM AUTHOR]

The overall success of worldwide mass vaccination in limiting the negative effect of the COVID-19 pandemics is inevitable, however, recent SARS-CoV-2 variants of concern, especially Omicron and its sub-lineages, efficiently evade humoral immunity mounted upon vaccination or previous infection. Thus, it is an important question whether these variants, or vaccines against them, induce anti-viral cellular immunity. Here we show that the mRNA vaccine BNT162b2 induces robust protective immunity in K18-hACE2 transgenic B-cell deficient (μMT) mice. We further demonstrate that the protection is attributed to cellular immunity depending on robust IFN-γ production. Viral challenge with SARS-CoV-2 Omicron BA.1 and BA.5.2 sub-variants induce boosted cellular responses in vaccinated μMT mice, which highlights the significance of cellular immunity against the ever-emerging SARS-CoV-2 variants evading antibody-mediated immunity. Our work, by providing evidence that BNT162b2 can induce significant protective immunity in mice that are unable to produce antibodies, thus highlights the importance of cellular immunity in the protection against SARS-CoV-2. Protective immunity against SARS-CoV-2 relies on both antibodies and a T cell dependent response, however, direct experimental evidence for the contribution of cellular immunity is limited. Here authors present a mouse model that is susceptible to SARS-CoV-2 and lacks B cells to demonstrate the emergence of efficient cellular immune response against SARS-CoV-2 upon vaccination or viral challenge. [ABSTRACT FROM AUTHOR]

Porcine deltacoronavirus (PDCoV) causes diarrhea and vomiting in neonatal piglets worldwide and has the potential for cross-species transmission. Therefore, virus-like particles (VLPs) are promising vaccine candidates because of their safety and strong immunogenicity. To the best of our knowledge, the present study reported for the first time the generation of PDCoV VLPs using a baculovirus expression vector system, and electron micrograph analyses revealed that PDCoV VLPs appeared as spherical particles with a diameter similar to that of the native virions. Furthermore, PDCoV VLPs effectively induced mice to produce PDCoV-specific IgG and neutralizing antibodies. In addition, VLPs could stimulate mouse splenocytes to produce high levels of cytokines IL-4 and IFN-γ. Moreover, the combination of PDCoV VLPs and Freund's adjuvant could improve the level of the immune response. Together, these data showed that PDCoV VLPs could effectively elicit humoral and cellular immunity in mice, laying a solid foundation for developing VLP-based vaccines to prevent PDCoV infections. [ABSTRACT FROM AUTHOR]

Objectives To analyse humoral and cellular immune response to mRNA COVID-19 vaccines in patients with GCA. Methods Consecutive patients with a diagnosis of GCA receiving two doses of BNT162b2 vaccine were assessed at baseline and 3 weeks from the second vaccine dose. Healthy subjects (n  = 51) were included as controls (HC). Humoral response was assessed with Spike-specific IgG antibody response (S-IgG) and neutralizing antibodies (NtAb). Specific T cell response was assessed by enzyme linked immunosorbent spot (ELISpot). Results Of 56 included patients with GCA, 44 were eligible after exclusion of previous evidence of COVID-19 and incomplete follow-up. A significant proportion of patients with GCA (91%) demonstrated antibody (S-IgG) response, but this was significantly lower than HCs (100%); P  < 0.0001. Neutralizing activity was not detected in 16% of patients with GCA. Antibody titres (S-IgG and NtAb) were significantly lower compared with HCs. Humoral response (S-IgG and NtAb) was significantly hampered by treatment with MTX. Cellular response was lacking in 30% of patients with GCA (vs 0% in HCs; P  < 0.0001). Cellular response was significantly influenced by the levels of baseline peripheral T-lymphocytes and by glucocorticoid treatment. Treatment with tocilizumab did not affect any level of the immune response elicited by vaccination. Conclusions Although patients with GCA apparently achieve a robust antibody seroconversion, there is a significant impairment of the neutralizing activity. MTX significantly reduced all levels of the humoral response. Up to one-third of patients do not develop a cellular immune protection in response to COVID-19 vaccination. [ABSTRACT FROM AUTHOR]

To better understand the development of SARS-CoV-2-specific immunity over time, a detailed evaluation of humoral and cellular responses is required. Here, we characterize anti-Spike (S) IgA and IgG in a representative population-based cohort of 431 SARS-CoV-2-infected individuals up to 217 days after diagnosis, demonstrating that 85% develop and maintain anti-S responses. In a subsample of 64 participants, we further assess anti-Nucleocapsid (N) IgG, neutralizing antibody activity, and T cell responses to Membrane (M), N, and S proteins. In contrast to S-specific antibody responses, anti-N IgG levels decline substantially over time and neutralizing activity toward Delta and Omicron variants is low to non-existent within just weeks of Wildtype SARS-CoV-2 infection. Virus-specific T cells are detectable in most participants, albeit more variable than antibody responses. Cluster analyses of the co-evolution of antibody and T cell responses within individuals identify five distinct trajectories characterized by specific immune patterns and clinical factors. These findings demonstrate the relevant heterogeneity in humoral and cellular immunity to SARS-CoV-2 while also identifying consistent patterns where antibody and T cell responses may work in a compensatory manner to provide protection. The persistence of the immune response to SARS-CoV-2 after recovery from infection is an indicator for subsequent protection against infection. Here the authors follow recovered patients and measure antibody and T cell responses and find that these two parts of the immune response may have different longevity. [ABSTRACT FROM AUTHOR]

The study of fundamental mechanisms of autoimmunity has been instrumental to clinical progress in the diagnosis and treatment of a range of immune-mediated inflammatory disorders. Dutch immunology has made major contributions to these developments, ranging from fundamental studies on immune cells, antibodies and cytokines to translational and clinical studies with targeted therapies in patients. In this paper we illustrate the progress made in our understanding of autoimmunity and the translational implications for human disease management by focusing on three areas: the autoantibody response in rheumatoid arthritis (RA), T-B cell interactions in Sjögren's syndrome (SS), and cytokine targeting in spondylarthritis (SpA). [ABSTRACT FROM AUTHOR]

Avian metapneumovirus (aMPV) causes respiratory disease and drops in egg production in chickens, and is routinely controlled by vaccination. However, the host's immune response to virulent challenge in vaccinated or unvaccinated broiler chickens is poorly characterized. We show that subtype B vaccination offers heterologous (subtype A challenge) and homologous (subtype B challenge) protection. Subtype B challenge caused significantly greater humoral antibody titres in vaccinated and unvaccinated chickens. In turbinate and lung tissues of unvaccinated-challenged chickens, IgA and IgY mRNA transcription was significantly up-regulated after subtype B challenge compared to subtype A. Cellular immunity (CD8-α and CD8-β) gene transcripts were significantly up-regulated during early and later stages of infection from subtype B or subtype A, respectively. Immune gene transcriptional responses (IL-1β, IL-6 and IL-18) were significantly up-regulated after challenge. Gene transcription results showed that mRNA expression levels of CD8-α, CD8-β, TLR3 and IL-6, particularly in turbinate and trachea tissues, are useful parameters to include in future aMPV vaccination-challenge studies. [ABSTRACT FROM AUTHOR]

Multiple myeloma patients are often treated with immunomodulatory drugs, proteasome inhibitors, or monoclonal antibodies until disease progression. Continuous therapy in combination with the underlying disease frequently results in severe humoral and cellular immunodeficiency, which often manifests in recurrent infections. Here, we report on the clinical management and immunological data of three multiple-myeloma patients diagnosed with COVID-19. Despite severe hypogammaglobulinemia, deteriorated T cell counts, and neutropenia, the patients were able to combat COVID-19 by balanced response of innate immunity, strong CD8+ and CD4+ T cell activation and differentiation, development of specific T-cell memory subsets, and development of anti-SARS-CoV-2 type IgM and IgG antibodies with virus-neutralizing capacities. Even 12 months after re-introduction of lenalidomide maintenance therapy, antibody levels and virus-neutralizing antibody titers remained detectable, indicating persisting immunity against SARS-CoV-2. We conclude that in MM patients who tested positive for SARS-CoV-2 and were receiving active MM treatment, immune response assessment could be a useful tool to help guide decision-making regarding the continuation of anti-tumor therapy and supportive therapy. Key messages: Immunosuppression due to multiple myeloma might not be the crucial factor that is affecting the course of COVID-19. In this case, despite pre-existing severe deficits in CD4+ T-cell counts and IgA und IgM deficiency, we noticed a robust humoral and cellular immune response against SARS-CoV-2. Evaluation of immune response and antibody titers in MM patients that were tested positive for SARS-CoV-2 and are on active MM treatment should be performed on a larger scale; the findings might affect further treatment recommendations for COVID-19, MM treatment re-introduction, and isolation measures. [ABSTRACT FROM AUTHOR]

Two recent papers published in Immunity and Cell Host & Microbe underline the great importance of B cells and of antibodies (Abs) in orchestrating crucial T helper cell type 2 (Th2) protective immune responses to gastrointestinal nematodes. The findings in animal models now raise major questions as to how B cells and Abs carry out these functions in humans. Here we discuss recent technological advances in humanizing animal models at the level of both Abs and their Fc-receptors, that might provide some answers. [Copyright &y& Elsevier]

Two methods are described for linking chlorambucil to antibodies. At low pH an association is formed which is not stable under physiological conditions and the cytotoxicity is the result of the independent action of chlorambucil and antibody. At pH 8 a more stable linkage is formed and this complex shows specific toxicity for cells carrying the appropriate antigen. Uncombined chlorambucil and antibody are more cytotoxic than chlorambucil alone, especially if the cells are exposed first to the chlorambucil. [ABSTRACT FROM AUTHOR]

T follicular helper (Tfh) cells help B cells to generate affinity-matured antibodies. Three papers in this issue of Immunity () provide information about the reciprocal relationship between B cells and Tfh cells. [ABSTRACT FROM AUTHOR]

Trichloroethylene (TCE) has been used for a variety of industrial and consumer cleaning purposes because of its ability to dissolve organic substances. The multisystem injuries include those of skin, liver, and kidney, which are defined as TCE hypersensitivity syndrome (THS). THS is a serious occupational health issue. However, the mechanism of immune dysfunction leading to organ injury is poorly understood. Many studies reveal that skin lesions and organ injury caused by TCE are consistent with type IV hypersensitivity, also called delayed hypersensitivity, mediated by T cells. However, many researchers found T cell-mediated type IV hypersensitivity could not account for the pathogenesis of THS fully. Humoral immunity, including immunoglobulins and complement activation, may also play a possible role in THS pathogenesis. This review will describe the history, current understanding, and future research directions of the mechanism of THS. [ABSTRACT FROM AUTHOR]

Hepatitis B is a DNA virus that infects liver cells and can cause both acute and chronic disease. It is believed that both viral and host factors are responsible for determining whether the infection is cleared or becomes chronic. Here we investigate the mechanism of protection by developing a mathematical model of the antibody response following hepatitis B virus (HBV) infection. We fitted the model to data from seven infected adults identified during acute infection and determined the ability of the virus to escape neutralization through overproduction of non-infectious subviral particles, which have HBs proteins on their surface, but do not contain nucleocapsid protein and viral nucleic acids. We showed that viral clearance can be achieved for high anti-HBV antibody levels, as in vaccinated individuals, when: (1) the rate of synthesis of hepatitis B subviral particles is slow; (2) the rate of synthesis of hepatitis B subviral particles is high but either anti-HBV antibody production is fast, the antibody affinity is high, or the levels of pre-existent HBV-specific antibody at the time of infection are high, as could be attained by vaccination. We further showed that viral clearance can be achieved for low equilibrium anti-HBV antibody levels, as in unvaccinated individuals, when a strong cellular immune response controls early infection. [ABSTRACT FROM AUTHOR]

CCL17 (TARC) function can be completely abolished by mAbs that block either one of two distinct sites required for CCR4 signaling. This chemokine is elevated in sera of asthma patients and is responsible for establishing inflammatory sites through CCR4-mediated recruitment of immune cells. CCL17 shares the GPCR CCR4, with CCL22 (MDC) but these two chemokines differentially affect the immune response. To better understand chemokine mediated effects through CCR4, we have generated chimeric anti-mouse CCL17 surrogate antibodies that inhibit function of this ligand in vitro and in vivo. The affinities of the surrogate antibodies for CCL17 range from 685 pM for B225 to 4.9 nM for B202. One antibody, B202, also exhibits weak binding to CCL22 (KD∼2 µM) and no binding to CCL22 is detectable with the second antibody, B225. In vitro, both antibodies inhibit CCL17-mediated calcium mobilization, β-arrestin recruitment and chemotaxis; B202 can also partially inhibit CCL22-mediated β-arrestin recruitment. Both B202 and B225 antibodies neutralize CCL17 in vivo as demonstrated by reduction of methacholine-induced airway hyperreactivity in the A. fumigatus model of asthma. That both antibodies block CCL17 function but only B202 shows any inhibition of CCL22 function suggests that they bind CCL17 at different sites. Competition binding studies confirm that these two antibodies recognize unique epitopes that are non-overlapping despite the small size of CCL17. Taking into consideration the data from both the functional and binding studies, we propose that effective engagement of CCR4 by CCL17 involves two distinct binding domains and interaction with both is required for signaling. [ABSTRACT FROM AUTHOR]

This study was undertaken to determine the effect of chronic exposure to sub-lethal concentrations of tannery effluent (TE) on the humoral antibody response and the cell-mediated immune response of the fish Cyprinous carpio. The LC value of the TE for C. carpio was determined by bioassay to be 3.8%. Sub-lethal concentrations of TE (0.6% and 0.3%) significantly suppressed the humoral and cell-mediated immune responses. Exposure of C. carpio to the TE had a significant effect on mean acceptance time (MAT) for transplanted scales. MAT was found to be 5-8 days for autografts and 4-7 days for allografts. The somatic indices of the kidney and spleen were reduced compared with controls. [ABSTRACT FROM AUTHOR]

Major histocompatibility complex class II plays a key role in the immune response, by presenting processed antigens to CD4+ lymphocytes. Major histocompatibility complex class II expression is controlled at the transcriptional level by at least four trans-acting genes: CIITA, RFXANK, RFX5 and RFXAP. Defects in these regulatory genes cause MHC class II immunodeficiency, which is frequent in North Africa. The aim of this study was to describe the immunological and molecular characteristics of ten unrelated Moroccan patients with MHC class II deficiency. Immunological examinations revealed a lack of expression of MHC class II molecules at the surface of peripheral blood mononuclear cells, low CD4+ T lymphocyte counts and variable serum immunoglobulin (IgG, IgM and IgA) levels. In addition, no MHC class II (HLA DR) expression was observed on lymphoblasts. The molecular analysis identified the same homozygous 752delG26 mutation in the RFXANK genes of all patients. This finding confirms the association between the high frequency of the combined immunodeficiency and the defect in MHC class II expression and provides strong evidence for a founder effect of the 752delG26 mutation in the North African population. These findings should facilitate the establishment of molecular diagnosis and improve genetic counselling for affected Moroccan families. [ABSTRACT FROM AUTHOR]

T-cells play a critical role in resistance to malaria, not only because they function as helper cells for an antibody response, but also because they serve as effector cells. Such cellular immunity is directly implicated in protection from sporozoites as well as from blood stage parasites. The aim of this study was to induce cell mediated immune responses to peptide antigens of Plasmodium vivax co-encapsulated with CpG oligodeoxynucleotide (ODN) in microparticles. In the present study, we have investigated the immunomodulatory effects of two CpG adjuvants, CpG 1826 and CpG 2006 to the five peptide antigens of Plasmodium vivax derived from circumsporozoite protein, merozoite surface protein-1, apical membrane antigen-1 and gametocyte surface antigen (Pvs24) in microparticle delivery. The T-cell proliferation response study of the cells collected from spleen, lamina propria and peyer's patches showed significantly high (p<0.001) stimulation index when primed with peptide antigens in microparticles co-encapsulating CpG ODN adjuvant as compared to peptide alone primed mice. The cytokine measurement profile of IFN-γ, TNF-α, IL-2, IL-4 and IL-10 in culture supernatants of cells primed with peptide antigens in microparticles co-encapsulating CpG ODN showed higher levels of IFN- γ followed by TNF-α and IL-2, with relatively low levels of IL-4 and IL-10. [ABSTRACT FROM AUTHOR]

In the present study we have evaluated the immunopotentiating activity of Rhodiola aqueous extract (RAE) in rats. The efficacy of RAE was determined by using strong antigen tetanus toxoid (TT) and weak antigen Ovalbumin (OVA). The dynamic changes in humoral and cell-mediated immune response were measured. The results indicated that the TT specific immunoglobulin levels were significantly enhanced by RAE and were at par with complete Freund’s adjuvant (CFA). The level of OVA induced antibody response was also enhanced by RAE. It was observed that TT and OVA in combination with CFA or RAE could evoke a significant delayed type hypersensitivity (DTH) response, confirming its potential to generate strong cell-mediated immunity (CMI). The anti-inflammatory or immunosuppressive effect of RAE was evaluated in adjuvant-induced arthritis model (AIA). RAE could not suppress the swelling response. Therefore, this study suggests that RAE has adjuvant/immunopotentiating activity in terms of humoral as well as cell-mediated immune response against strong antigen like TT and weak antigen like OVA. [ABSTRACT FROM AUTHOR]

The recognition of foreign antigens by T lymphocytes is essential to most adaptive immune responses. It is driven by specific T-cell antigen receptors (TCRs) binding to antigenic peptide–major histocompatibility complex (pMHC) molecules on other cells. If productive, these interactions promote the formation of an immunological synapse. Here we show that synaptic TCR–pMHC binding dynamics differ significantly from TCR–pMHC binding in solution. We used single-molecule microscopy and fluorescence resonance energy transfer (FRET) between fluorescently tagged TCRs and their cognate pMHC ligands to measure the kinetics of TCR–pMHC binding in situ. When compared with solution measurements, the dissociation of this complex was increased significantly (4–12-fold). Disruption of actin polymers reversed this effect, indicating that cytoskeletal dynamics destabilize this interaction directly or indirectly. Nevertheless, TCR affinity for pMHC was significantly elevated as the result of a large (about 100-fold) increase in the association rate, a likely consequence of complementary molecular orientation and clustering. In helper T cells, the CD4 molecule has been proposed to bind cooperatively with the TCR to the same pMHC complex. However, CD4 blockade had no effect on the synaptic TCR affinity, nor did it destabilize TCR–pMHC complexes, indicating that the TCR binds pMHC independently of CD4. [ABSTRACT FROM AUTHOR]

Background: We conducted a Phase I dose escalation trial of ADVAX, a DNA-based candidate HIV-1 vaccine expressing Clade C/B' env, gag, pol, nef, and tat genes. Sequences were derived from a prevalent circulating recombinant form in Yunnan, China, an area of high HIV-1 incidence. The objective was to evaluate the safety and immunogenicity of ADVAX in human volunteers. Methodology/Principal Findings: ADVAX or placebo was administered intramuscularly at months 0, 1 and 3 to 45 healthy volunteers not at high risk for HIV-1. Three dosage levels [0.2 mg (low), 1.0 mg (mid), and 4.0 mg (high)] were tested. Twelve volunteers in each dosage group were assigned to receive ADVAX and three to receive placebo in a double-blind design. Subjects were followed for local and systemic reactogenicity, adverse events, and clinical laboratory parameters. Study follow up was 18months. Humoral immunogenicity was evaluated by anti-gp120 binding ELISA. Cellular immunogenicity was assessed by a validated IFNc ELISpot assay and intracellular cytokine staining. ADVAX was safe and well-tolerated, with no vaccine-related serious adverse events. Local and systemic reactogenicity events were reported by 64% and 42% of vaccine recipients, respectively. The majority of events were mild. The IFNc ELISpot response rates to any HIV antigen were 0/9 (0%) in the placebo group, 3/12 (25%) in the low-dosage group, 4/12 (33%) in the mid-dosage group, and 2/12 (17%) in the high-dosage group. Overall, responses were generally transient and occurred to each gene product, although volunteers responded to single antigens only. Binding antibodies to gp120 were not detected in any volunteers, and HIV seroconversion did not occur. Conclusions/Significance: ADVAX delivered intramuscularly is safe, well-tolerated, and elicits modest but transient cellular immune responses. Trial Registration: Clinicaltrials.gov NCT00249106. [ABSTRACT FROM AUTHOR]

How B cells affect the outcome of transplants is a question of enduring interest. Initial efforts to answer that question suggested, wrongly, that B cells have no impact on transplantation. Now, however, B cells are known to influence not only the outcome of vascularized grafts through the production of anti-donor antibodies but also the competence of cellular immunity through a number of physiologic functions. In this study, we explain why the importance of B cells was overlooked in the past and consider the range of noncognate functions of B cells that may determine the outcome of transplants. [ABSTRACT FROM AUTHOR]

The interaction between immune responses and hepatitis B virus (HBV) is coordinated between innate and adaptive immunity. Anti-HBs antibodies protect the host by blocking the binding ability of HBV. Anti-HBc antibodies are detected with persistent HBV infection. The presence of anti-HBe antibodies is often associated with recovery from active diseases and is clinically used as a benchmark to assess response to treatment. Our studies have revealed that the anti-HBV immunoglobulins secreted are different in subclass patterns in different HBV infection status populations. These revelations may help to understand HBV escape and persistent infection and to develop strategies for prevention and therapeutic management of HBV infection. [ABSTRACT FROM AUTHOR]

Receptors for the Fc region of immunoglobulin G (FcγRs) are expressed on a broad range of haematopoietic cell types and are responsible for regulating antibody production and linking the humoral and effector responses. In response to a number of stimuli, such as cytokine signals or inflammation, FcγR expression at the cell surface is dynamically regulated. On B cells, we observed what appeared to be a correlation between CD22 expression and FcγRIIb expression when the latter was varied in a number of models. Further investigation revealed that this was specific to a particular anti-CD22 monoclonal antibody, which appeared to require stabilization by interaction with FcγRIIb for optimal binding to CD22. Since alterations in the regulation of FcγR expression are important in controlling immune responses and have been associated with a number of immune-mediated disease states, we suggest that it might be prudent to confirm the expression of cell surface markers by two independent methods. Furthermore, because the efficacy of therapeutic antibodies may depend upon their interaction with FcγRs, our results are relevant to their design and assessment. [ABSTRACT FROM AUTHOR]

Objective: To evaluate cell-mediated immune (CMI) response in diabetic and non-diabetic tuberculosis (TB) patients and healthy subjects in response to complex, fractionated and single antigens of Mycobacteriumtuberculosis. Material and Methods: Peripheral blood mononuclear cells (PBMC) were obtained from patients suffering from pulmonary TB and type II diabetes (n = 7), pulmonary TB without diabetes (n = 10) and healthy subjects without TB and diabetes (n = 10). PBMC were assessed for CMI responses in antigen-induced proliferation assays in response to complex mycobacterial antigens (whole cells, cell walls and culture filtrate of M. tuberculosis), a battery of naturally purified or recombinant produced secreted (ESAT6, MPT59, MPT64 and MTB38) and cytosolic (MTB10, MTB70, ML10, ML28, ML36, ML65 and MB65) mycobacterial antigens and fractionated culture filtrate proteins (fractions F1–F10) of M. tuberculosis. Results:The majority (>70%) of diabetic and non-diabetic TB patients and healthy subjects responded to the complex antigens of M. tuberculosis. However, among the single antigens, ESAT6 was most frequently recognized by TB patients with and without diabetes, but least recognized by healthy subjects. The secreted antigens MPT59 and MPT64 were recognized by all the groups, whereas the cytosolic antigens were recognized best by healthy subjects. When tested with fractionated secreted proteins present in the culture filtrate of M. tuberculosis, the best responses in both diabetic and non-diabetic TB patients were obtained with fractions containing low-molecular-weight proteins. Conclusions: Diabetic and non-diabetic TB patients respond frequently to secreted low-molecular-weight ESAT6 antigen of M. tuberculosis, indicating that this antigen may be useful in the diagnosis of TB in both the groups. Copyright © 2008 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: A number of reports have demonstrated that rodents immunized with DNA vaccines can produce antibodies and cellular immune responses presenting a long-lasting protective immunity. These findings have attracted considerable interest in the field of DNA vaccination. We have previously described the prophylactic and therapeutic effects of a DNA vaccine encoding the Mycobacterium leprae 65 kDa heat shock protein (DNA-HSP65) in a murine model of tuberculosis. As DNA vaccines are often less effective in humans, we aimed to find out how the DNA-HSP65 stimulates human immune responses. Methods: To address this question, we analysed the activation of both human macrophages and dendritic cells (DCs) cultured with DNA-HSP65. Then, these cells stimulated with the DNA vaccine were evaluated regarding the expression of surface markers, cytokine production and microbicidal activity. Results: It was observed that DCs and macrophages presented different ability to uptake DNA vaccine. Under DNA stimulation, macrophages, characterized as CD11b+/CD86+/HLA-DR+, produced high levels of TNF-alpha, IL-6 (pro-inflammatory cytokines), and IL-10 (anti-inflammatory cytokine). Besides, they also presented a microbicidal activity higher than that observed in DCs after infection with M. tuberculosis. On the other hand, DCs, characterized as CD11c+/CD86+/CD123-/BDCA-4+/IFN-alpha-, produced high levels of IL-12 and low levels of TNF-alpha, IL-6 and IL-10. Finally, the DNA-HSP65 vaccine was able to induce proliferation of peripheral blood lymphocytes. Conclusion: Our data suggest that the immune response is differently activated by the DNA-HSP65 vaccine in humans. These findings provide important clues to the design of new strategies for using DNA vaccines in human immunotherapy. [ABSTRACT FROM AUTHOR]

Circulating immune complexes (IC) and levels of IC-induced cytokines have been correlated with complement activation and autoantibody profiles in systemic lupus erythematosus (SLE). SLE sera were analysed concerning levels of immune complexes (IC), classical complement function and different antinuclear and anti-C-reactive protein (CRP) autoantibodies. Blood mononuclear cells from healthy donors were stimulated with isolated IC and production of interleukin (IL)-10, IL-6 and IL-12p40 was measured. Functional experiments revealed that increased levels of IC-induced cytokines were associated with both increased classical complement activation and the occurrence of anti-Sjögren's syndrome A (SSA) and anti-SSB but not other autoantibodies. Biochemical measurement of circulating IC showed that the degree of complement activation and the occurrence of anti-SSA were synergistically associated with levels of circulating IC in SLE sera, as complement activation was a prerequisite for the enhancing effect of anti-SSA. Anti-CRP was associated with complement activation, but not with other autoantibodies. Our results indicate that anti-SSA and possibly anti-SSB antibodies influence IC formation and subsequent IC-induced cytokine induction, and that they thereby participate in the inflammatory process in active SLE. [ABSTRACT FROM AUTHOR]

Cellular immune responses have been shown to be associated with differential evolutions of E. multitocularis infection in intermediate hosts. A relationship between course of delayed-type hypersensitivity (DTH) against parasitic antigens and receptivity of murine strains has been demonstrated recently. The aim of this study was to correlate resistance and sensitivity to E. multilocutaris infection with the phenotypic patterns of cells within the peri parasitic granuloma. Evolution of the ratios. macrophages/T lymphocyte and Lyl/Ly2 T lymphocytes, was associated with the receptivity of the strains. Persistence of numerous L3T4-I-T lymphocytes and low numbers of macrophages and Ly2 + T lymphocytes were observed in the "resistant' C57BL,10 mice. Comparison of the results with course of the DTH against E. multilocularis, antigens showed that the particular phenotypic pattern observed in resistant mice was associated with a particular profile of DTH after infection. These results and similar observations in human alveolar echinococcosis suggest that cell composition of the periparasitie granuloma might be of crucial importance in controlling the spontaneous development of E. multitocularis larvae in the intermediate host. [ABSTRACT FROM AUTHOR]

Species- or strain-related differences in receptivity of intermediate hosts to E. multitocularis larvae could be related to differences in specific cellular immune response of the host. In order to test this hypothesis, we assessed the delayed-type hypersensitivity (DTH) to E. multilocutaris antigens (EmAg) in mice of three strains differing by their sensitivity (AKR and C57BL.6) or resistance (C57BL.10) to E. multilocutaris infection. DTH was determined by measuring in vivo the foot-pad response 24 h after an EmAg antigenic challenge. The level of positive response was evaluated in immunized mice; however, a typical DTH response was only observed by immunizing mice with a strong adjuvant schedule. Course of DTH in the immunized mice was shown to be somewhat different in sensitive and resistant mice. The differences were much more marked in mice infected with proliferative E. multitocularis larvae. The levels of the footpad response was significantly higher in resistant mice, although the peak of the reaction was obtained later than in sensitive mice, DTH. expressed by the foot-pad response against EmAg remained significant for the entire period of observation in sensitive as well as in resistant mice. There was no correlation between receptivity of the murine hosts and levels of specific antibodies against EmAg. These results suggest a relationship between resistance to E. multitocularis infection and intensity and/or course of DTH in mice. The resistance could be mediated by some particularities of the in situ cellular immune response in the periparasitie granuloma. [ABSTRACT FROM AUTHOR]

The possible pathogenetic role of lymphocytes sensitized to liver antigens was investigated in CBA mice in which sublethal hepatic necrosis had been induced by carbon tetrachloride (CCl4). Sensitized lymphocytes from CCl4-treated mice were administered to synergic recipients. The recipients developed sensitivity to liver antigens but showed no evidence of liver damage. The cell mediating the immune response both in the donor and the recipient was a T cell. This was demonstrated further by studies involving mice rendered T cell deficient. These mice did not develop sensitized lymphocytes when they were treated with CCl4 but the extent of liver damage was similar in both T cell-depleted and intact animals. These findings suggest that T cell sensitization to liver antigens occurs as a result of toxic liver damage and does not play a role in the pathogenesis of the hepatic necrosis. [ABSTRACT FROM AUTHOR]

Using cloned human T lymphocytes reactive with a 24 amino acid peptide (p20) of the carboxyl terminus of the HA-1 molecule of influenza haemagglutinin (HA), we have investigated the ability of solid-phase antigen to induce antigen-specific T-cell proliferation. The activation by nitrocellulose- bound virus and p20 was accessory-cell dependent and was not caused by immobilized antigen directly cross-linking the specific receptors. Furthermore, we report that separation of complex antigen mixtures such as influenza virus and HA by polyacrylamide gel electrophoresis under denaturing conditions (SDS-PAGE) followed by transfer to a nitrocellulose membrane can be used to allow direct screening of individual polypeptides in T-cell proliferation assays. With this immunoblotting procedure the antigenic site recognized by HA-reactive T cells was confirmed to reside in the HA-i molecule of influenza virus of only the appropriate subtype. The general application of this approach is discussed in the case of infections and autoimmune diseases in which the immune response is predominantly T-cell mediated and where antibody studies may fail to identify key antigenic determinants involved in the activation of T cells. [ABSTRACT FROM AUTHOR]

Examines the formation of antibodies to the respective idiotypes of myeloma proteins produced by MOPC plasmocytoma tumours of BALB/c origin. Description of the biological characteristics and morphology of the IR202 transplantable immunocytoma tumour in rats; Presentation of the 202M protein molecules on the macrophage surface; Development of antibodies specific to individual antigenic determinant of the monoclonal IgM.

Cell-mediated immunity and antibody production to cartilage antigens were studied in rabbits. From day 3 of immunization an inhibition of leucocyte migration was observed in animals immunized with collagen-free fractions of bovine nasal or human rib cartilage. Delayed cutaneous hypersensitivity was elicited between 5 and 6 days and the circulating antibodies were demonstrated by passive haemagglutination on day 9. No significant correlation was observed between the antibody production and the cell-mediated immtinity. Cell-mediated immune responses to cartilage antigens and to purified protein derivative were distinctly different, but the two antigens influenced one another when they were administered together. The 'species common' antigen of connective tissues may be primarily responsible for the early immune reactions. [ABSTRACT FROM AUTHOR]

The ability to identify antigens associated with an infection has generally relied on the use of serum antibodies produced by infected or previously exposed individuals. A major drawback with the use of serum is that it does not necessarily reflect the local antibody response at mucosal tissue sites. This study describes an approach that allows the use of antibodies generated close to the infection site to detect the transient expression of stage-specific antigens during infection with the gastrointestinal parasite Haemoachus contortus. This was achieved by infecting immune sheep with H. contortus larvae and removing the abomasal lymph nodes draining the infection site shortly after the challenge infection. Antibody-secreting cell (ASC) probes were generated from these lymph nodes alter short-term in vitro culture of cell suspensions, which allowed the accumulation of antibodies secreted by in vivo-induced ASC into the culture supernatant. Lymph node culture supernatants (= ASC probes) from immune sheep challenged 5 days previously were used to probe Western blots of third and fourth stage larval preparations, and revealed distinct reactivity to larval antigens. No antibody reactivity to larval antigen preparations was detected in sheep that were not challenged. The number of antigens identified using ASC probes was significantly restricted compared to either pre- or post-challenge sera. In contrast to the variability of the serum response, the specificity of ASC probes was highly repeatable between different sheep. ASC probes were also used to purify a H. contortus larval antigen by affinity chromatography, which allowed limited biochemical studies to be undertaken. The antigen(s) recognized by the ASC probes were shown to be expressed on the surface of the larvae. These studies illustrate the use of a novel means of studying the local antibody response close to a mucosal infection site in order to identify and isolate stage-specific antigens expressed during infection. [ABSTRACT FROM AUTHOR]

The heavy chain variable region (VH) and the κ light chain of the anti-progesterone monoclonal antibody (mAb) DB3, have been expressed as a single-chain three-domain polypeptide, designated VH/K, and secreted into the periplasmic space of Escherichia coli (E. coli). The linker sequence was derived from the VH-CH1 elbow region. The Cκ domain provides a sensitive detection tail for Western blotting and enzyme-linked immunosorbent assay (ELISA). Periplasmic extracts of transformed E. coli contained material that bound progesterone and related steroids with similar specificity and affinity to DB3, and displayed the DB3 idiotype and κ chain epitopes. Reference to the crystal structure of DB3 suggests that all the characteristics of the combining site interaction with steroids are retained in the bacterially expressed material. Western blotting demonstrated material with a molecular weight equivalent to three domains after reduction, but six domains in the unreduced state, suggesting that the VH/K polypeptide is assembled in the periplasm as a disulphide-bridged dimer. The VH/K construct provides a novel route to expression of antibody combining sites in E. coli for antibody engineering. [ABSTRACT FROM AUTHOR]

An evaluation of the specificity of antigen binding receptors possessed by cells involved in cellular immune responses and by cells in the antibody synthesizing line was made in order to determine to what extent each cell type could distinguish between closely related mono-ε-DNP-oligo-L-lysines. The antigen binding receptors of cells involved in cellular immune responses were studied by the elicitation of delayed hypersensitivity reactions in vivo and by the stimulation of DNA synthesis by lymph node cells in vitro using 1-ε-DNP-nona-L-lysine and 9-ε-DNP-nona-L-lysine. These experiments demonstrated that closely related compounds could be distinguished by this cell population. On the other hand, serum antibody from animals immunized with 1-ε-DNP-nona-L-lysine did not regularly distinguish between various mono-ε-DNP-oligo-L-lysines of differing immunogenicity or between 1-ε-DNP-nona-L-lysine and 9-ε-DNP-nona-L-lysine. Serum antibody specificity is assumed to reflect the specificity of the receptors possessed by the precursors of antibody producing cells. Thus, it appears likely that the cells involved in cellular immune responses or functioning as 'helper' cells in the stimulation of antibody synthesis by other cells are capable of determining the immunogenicity of a compound. On the other hand, precursors of antibody producing cells, at least in primed animals and in the mono-ε-DNP-oligo-L-lysine response, do not appear to make distinctions between peptides of differing immunogenicity. [ABSTRACT FROM AUTHOR]

The technique of equilibrium density gradient centrifugation has been used to study the antibody forming cells (AFC) produced in the Lewis rat and the toad Bufo marinus in response to polymerized flagellin protein antigen. In both animals the AFC at the peak of the response were heterogeneous in density, and formed many separate peaks, as has been observed previously with sheep erythrocyte antigen. Two lines of evidence suggested the various peaks were of biological significance. The earliest AFC found in the rat spleen were simpler in density profile than the AFC at the peak, although a complex 'steady-state' situation developed soon after. In the toad, a definite sequence of density peaks appeared progressively during the whole response. In the rat, the AFC making different classes of antibody gave different density profiles, and could be partially separated from each other. The density separation technique may be useful for studying the differentiation and maturation of antibody forming cells. [ABSTRACT FROM AUTHOR]

We observed that the volume of any anti-HSA serum needed to bind 50 per cent of the antigen is a linear function of the amount of antigen present in the reaction mixture over three log units. The slope is characteristic of each anti- serum and reflects the ‘avidity’ of the antibodies. By using this quantitative index we found that the avidity of antibodies produced during the secondary adoptive response depends on the number of the cells transferred : few cells will produce antibodies of lower avidity than many cells. The dose of antigen given as a booster also influences the quality of the antibody produced; in the extreme case where some primed cells were rendered ‘tolerant’ by supra-optimal doses of challenging antigen, substantial amounts of low avidity antibodies were synthesized. The results can be explained by competition for antigen among competent cells, favouring those cells which carry antibody sites with high affinity for the corresponding antigenic determinant. [ABSTRACT FROM AUTHOR]

The intravenous transfer of mesenteric lymph node cells from intragastrically immunized donors led to the appearance of agglutinins in the sera of recipients. Other lymph node cells from these donors did not impart such a response in the recipients. The serum agglutinin titres in recipients were dependent on the immune state of the donor where the better immunization of the donor gave a high and prolonged response in the recipients. The antibody synthesizing property could be conveyed to the recipients by the intravenous transfer of any of the lymph node cells and spleen tissue using intravenously immunized donors. However, in intragastrically immunized donors, it was only the mesenteric lymph node cells that could effectively transfer this factor. Thus, the sensitization of the regional lymph nodes is important in cell transfer mechanism. The antibody that appeared in recipients after the cell transfer was not due to the transfer of preformed antibody but was due to the active participation of the recipient in the antibody synthesis. The lymph node cells tested in vitro were negative for Vibrio cholerae agglutinins. [ABSTRACT FROM AUTHOR]

The article analyses the cooperation between different cells in the immune response. It has long been recognized that the immune response to foreign substances is of two basic kinds, immediate hypersensitivity, associated with and transferable by serum antibody, and delayed hypersensitivity, only transferable by, and therefore presumably mediated by, living cells from the lymphoid organs, notably spleen and lymph nodes. The study of skin graft rejection in mice added a third kind of reaction, but since this type of immunity, too, could be easily transferred from immune to normal animals by lymphoid cells, it was eventually put in the same category as the delayed response, under the general title of cell mediated immunity.

Background: In a recent study we had evidence that sulphite oxidase (SO) may be a relevant autoantigen in primary sclerosing cholangitis (PSC). Aim of the present study was, therefore, to analyse humoral and cellular immune-reactivity towards SO in these patients in more detail.Methods: Sera from 53 patients with PSC (30 untreated and 23 treated with ursodeoxycholic acid [UDCA] at time of analysis), from 422 patients with different hepatic and non-hepatic disorders, and from 50 healthy individuals were tested by ELISA for antibodies against full-length-SO (SO-fl) and its three major domains expressed in E.coli (SO-I, SO-II, SO-III). For epitope-mapping, 29 overlapping peptides were used. Peripheral blood mononuclear cells (PBMC) were obtained from 33 PSC-patients and analysed for SO-induced proliferation, production of cytokines, and expression of the activation marker cluster of differentiation (CD) 69.Results: 43% of the 30 untreated and 26% of the 23 treated PSC-patients had IgG anti-SO-antibodies predominantly reacting with SO-fl, SO-I and SO-II. Antibody-reactivity decreased after UDCA-treatment. Prevalence and reactivity of anti-SO-antibodies were significantly higher in PSC than in patients with other hepatic and non-hepatic disorders. Epitope mapping revealed no distinct immuno-dominant regions within SO. Incubation of PBMC from PSC-patients (but not from controls) with SO-antigens revealed an activation of B-cells and a T-helper cell type-2 reaction pattern (production of interleukin [IL]-13, IL-10).Conclusions: PSC-patients show humoral and cellular immune response towards SO. Antibodies may be predominantly directed against conformational epitopes. SO enhances in vitro especially T-helper cell type-2 immune-reactions, which may be pro-fibrotic. SO is a detoxifying enzyme present also in bacteria; further studies analysing its role in the aetiology and pathogenesis in PSC may, therefore, be important. [ABSTRACT FROM AUTHOR]