Search

Mycobacterium tuberculosis (Mtb) early secreted protein antigen 6 (ESAT-6) and culture filtrate protein 10 (CFP-10) are among candidate vaccines against tuberculosis (TB). Results of experimental animal models show that these antigens are associated with induction of strong T cell immunity [interferon (IFN)-γ production], while others report that these proteins as virulent factors involved in pathogenicity of Mtb infection. However, the role of ESAT-6/CFP-10 during natural Mtb infections in humans has not been established. In this paper we present results of a longitudinal study from an Mtb-infected human population from an endemic setting. Whole blood assay was used to determine levels of IFN-γ, tumour necrosis factor (TNF)-α and interleukin (IL)-10 against rESAT-6/CFP-10 in TB patients, household contacts and community controls. The levels of IFN-γ, TNF-α and IL-10 against rESAT-6/CFP-10 at baseline were significantly higher in patients and community controls than in household contacts. In patients, no significant difference was observed in the level of these cytokines before and after chemotherapy whereas, in contacts, the level of these cytokines increased significantly and progressively over time. The study shows that the levels of IFN-γ, TNF-α and IL-10 against rESAT-6/CFP-10 are depressed during Mtb infection or exposure but are elevated during clinical TB. Our findings from a study of naturally infected human population suggest that IFN-γ, TNF-α and IL-10 against rESAT-6/CFP-10 are markers for clinical TB but not for protective immunity. [ABSTRACT FROM AUTHOR]

Bacille Calmette-Guérin (BCG), developed a century ago, is the only licensed tuberculosis (TB) vaccine in use to date. The protective efficacy of BCG against TB varies with no apparent protection in some population, and mechanisms of its immune protection is poorly known, and yet BCG is the most widely used vaccine, with more than 4 billion BCG-vaccinated children globally. BCG is probably the only licensed vaccine currently in use believed to mediate immune protection through the production of interferon (IFN)-γ by CD4 T cells, which in turn activates macrophages to kill Mycobacterium tuberculosis ( Mtb). Currently, a number of new TB candidate vaccines are in different phases of clinical trial. The majority of these new vaccines are either recombinant forms of BCG or prime boosters of BCG (rBCG) and their immunogenicity is tested using BCG as a benchmark by measuring specific IFN-γ produced by CD4+ T cells as a protective immune marker. However, some recent studies that examined mechanisms of immune protection of BCG in animals and humans have reported a lack of correlation between IFN-γ production by CD4 cells and BCG-induced immune protection. These studies point to the fact that there is a missing link in our understanding of TB immunology. Conversely, there is emerging evidence that other T cell subsets (gammadelta, γδ), CD8+ T cells and natural killer (NK) cells may play a vital role in immune protection against Mtb infection and BCG-induced immune protection. γδ T cells and NK cells, which were considered to be part of the innate immunity in the past, have been shown to develop immunological memory upon re-encounter with the same pathogen. In this paper, the controversy over the role of IFN-γ as a marker for protective immunity against TB, and emerging data on the role of γδ T cells, CD8+ and NK cells in TB immunology, will be presented. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system with a poorly defined and complex immunopathogenesis. Although initiated by reactive T cells, persistent inflammation is evident throughout the disease course. A contribution from complement has long been suspected, based on the results of pathological and functional studies which have demonstrated complement activation products in MS brain and biological fluids. However, the extent and nature of complement activation and its contribution to disease phenotype and long-term outcome remain unclear. Furthermore, functional polymorphisms in components and regulators of the complement system which cause dysregulation, and are known to contribute to other autoimmune inflammatory disorders, have not been investigated to date in MS in any detail. In this paper we review evidence from pathological, animal model and human functional and genetic studies, implicating activation of complement in MS. We also evaluate the potential of complement components and regulators and their polymorphic variants as biomarkers of disease, and suggest appropriate directions for future research. [ABSTRACT FROM AUTHOR]

Prolonged exposure to antigens may result in high IgG4 antibody titres as was shown in a previous paper (Aalberse et al., 1983b). In novice bee keepers, a shift in the IgGI/IgG4 ratio of the response against phospholipase-A (PLA; a major component of bee venom) occurred. This resulted in an IgG4-dominated response after approximately 2 years of bee-keeping experience. Subject of the present study was the influence of relatively high concentrations of IgG4 antibodies on the biological activity of immune complexes. In the PLA antigen model, it was demonstrated (a) that IgG4-containing immune complexes do not activate complement and (b) that lgG4 antibodies effectively inhibit immune precipitation and complement activation by IgG1 antibodies. Evidence is provided that lgG4 antibodies inhibit binding of Clq to IgG1 in mixed, IgG1- and lgG4-containing complexes. It is proposed that IgG4 antibodies protect against the biological effects of the complement-fixing IgG subclasses. For this reason, determination of the total IgG response or just determination of antibody activity in the complement-fixing isotypes is insufficient in immune-complex diseases. The modulating effect of the non-complement-fixing isotypes should be taken into account to predict the biological activity of the immune complexes. [ABSTRACT FROM AUTHOR]

The role of the spleen in humoral antibody formation and in the pathogenesis of immune thyroiditis was studied by splenectomizing four monkeys (Macaca mulatta) prior to thyroid isoimmunization. Splenectomized animals, as well as intact controls, were subjected to sequential immunizations and the course of the immune disease was followed by periodic thyroid biopsies and frequent humoral antibody measurements over a period exceeding 1 yr. Extirpation of the secondary lymphoid organ markedly inhibited agglutinating antibody response, prevented formation of complement-fixing antibodies, but had no effect on thyrocytotoxic antibodies. In animals subjected to immunization in complete adjuvant a trend towards a decrease in serum complement levels was evident at the terminal stages of the experiments. Despite the inhibitory effects on some immunological parameters, splenectomy in monkeys prior to thyroid isoimmunization did not interfere with the initiation and progression of pathological processes in the thyroid. Indeed in all splenectomized animals immunized with thyroid plus complete adjuvant, fibrotic thyroid lesions (4+) with virtual obliteration of thyroid follicles were evident, in some as early as 120 days after primary immunization; in contrast, non-fibrotic and less severe lesions were noted in the intact animal despite being repeatedly subjected to similar immunization procedures over a period of 340 days. Immunization in the absence of complete adjuvant did not induce thyroid lesions in the presence or absence of spleen. In all animals with severe thyroid lesions, thyroid function decreased as revealed by T4 and 131I-T3 resin uptake measurements. Paper electrophoresis of serum specimens from a monkey subjected to thyroid isoimmunization in complete adjuvant (and after equilibration with 125I-T4) showed a pronounced retention of 125I-T4 radioactivity at the gamma globulin region indicating formation of antibodies to thyroxine. On the other hand, in sera with a low thyroid antibody titre as in splenectomized monkeys or in those animals immunized within complete adjuvant, T4-binding antibodies were not evident. It is concluded that removal of the spleen prior to thyroid isoimmunization in monkeys, rather than inhibiting the severity of the disease may even aid and abet immunopathogenic events destructive to the thyroid. [ABSTRACT FROM AUTHOR]

Two liver-specific antigens are known: a water soluble protein (LP-2) and a water insoluble macromolecular low density lipoprotein (LP-1). In this paper the relative role of the two antigens in the development of experimental immune hepatitis has been investigated. Immunization of rabbits with a human preparation containing both antigens, led in all animals to lesions characteristic of an immune hepatitis. Immunization of the animals with a purified water soluble liver protein proved less efficient: only two out of six animals developed characteristic lesions which were less severe than those in the first group. It was deduced that although not a prerequisite, the liver-specific lipoprotein plays an important supportive role in the development of immune hepatitis, [ABSTRACT FROM AUTHOR]

In a previous paper it had been shown that up to 40% of human peripheral lymphocytes will make rosettes with sheep red cells. In this study the inhibitory effect of antilymphocyte serum (ALS) and of certain other preparations on this rosette phenomenon is described. ALS was prepared in horses by injection of human peripheral lymphocytes and rosette-inhibiting, cytotoxic and agglutinating titres were determined during immunization. The ALS had been tested in vivo by regional administration to vervet monkeys bearing skin allografts. It was found t h a t the peak of rosette-inhibiting titre appeared to provide a good index of immunosuppressive activity. These peaks, and the accompanying periods of immunosuppressive activity, were of short duration, in contrast to the levels of cytotoxic and agglutinathig titres. Antihuman lymphocyte sera had considerable rosette-inhibiting titres against the lymphocytes of the baboon (Papio papio) but little against those of the vervet monkey (Cercopithecus aethiops). Inhibition by ALS of the phenomenon described by us is unaffected by complement. Antihuman globulin serum and phytohaemagglutinin had no inhibitory effect. Digestion of ALS with pepsin to obtain the F (ab')2 fragment had only a slight effect on rosette-inhibiting titres, while it reduced the cytotoxic activity very considerably. The phenomenon described by us is probably different from that reported by other workers, in which only a small proportion of lymphocytes form rosettes. [ABSTRACT FROM AUTHOR]

This paper describes the course of infection and development of immunity in guinea-pigs after intradermal inoculation of Leishmania enriettii, and the use of in vivo and in vitro techniques to characterize the immunological response to infection and artificial immunization. Inoculation of 106 amastigotes into the ear produced a nodule which ulcerated in 2-3 weeks and healed in 8-16 weeks. 8% of animals developed cutaneous metastases which healed with the original lesions. Histology of the primary lesions showed epidermal necrosis overlying a mass of parasitized macrophages which, after 4-6 weeks, became surrounded and infiltrated by lymphocytes. Histological changes in the draining lymph node began after 3 days and proceeded for 6 weeks; both germinal centres and paracortical areas were hyperplastic and the medulla contained many plasma cells. Superinfection produced an 'isophasic" lesion, but reinfection after healing elicited only a delayed hypersensitivity response. Artificial immunization with soluble and insoluble antigenic extracts of L. enriettii in Freund's complete adjuvant partially protected against infection; extracts of other leishmanial species Jailed to protect. Immunological paralysis, attempted with intravenous injections of soluble antigen, increased the severity of subsequent infection. Both infection and immunization were accompanied by delayed hypersensitivity which could be transferred passively by lymphoid cells. Cell-mediated immunity was studied in vitro by the ability of soluble leishmanial antigens to transform lymphokine, to inhibit macrophage migration, and to induce the production of lymphokine factors from lymphocytes of sensitized animals. A target cell system was devised in which sensitized lymphocytes destroyed monolayers of parasitized macrophages. Cross reactivity of leishmanial with mycobacterial antigens was shown in skin tests and in target cell destruction, but not in cell transfer or in the other cell culture systems, The phagocytic activity of peritoneal macrophages from recovered animals was increased for homologous but not for heterologous species of Leislumania; the growth of ingested organisms was not however reduced. Circulating antibodies were not demonstrated by passive cutaneous anaphylaxis, or by agglutination of antigen coated sheep erythrocytes, in the sera of infected or convalescent animals, although some convalescent animals showed active cutaneous anaphylaxis. However, antibodies were demonstrated by both these techniques in immunized animals, which also showed anaphylactic and Arthus hypersensitivity when skin tested with. the soluble antigens. The results are taken to indicate that cellular mechanisms are prominent in the development of immunity of the guinea-pig against L. enriettii, and ways in which the host may eliminate the parasite are discussed. It is concluded that this model provides an experimental counterpart of human cutaneous leishmaniasis and that it is suitable for the analysis of the role of cell-mediated specific immunity in resistance to intracellular infection. [ABSTRACT FROM AUTHOR]

The article informs that the there are no reliable quantitative indices of the "functional capacity" of the immunological system in man. The occurrence of infections, the levels of immunoglobulins, the elicitation of coetaneous delayed hypersensitivity reactions, and the antibody response to various vaccine antigens have all been used, but standard routine methods have not been developed. This paper describes an attempt lo use antibody production to flagellin as one index of the functional capacity of the immune system, and describes the response in subjects considered to have a normal antibody-producing system.

STAT1 dysfunction causes a wide range of immune dysregulation phenotypes, which have been classified into four disease types, namely, (i) autosomal recessive (AR) complete STAT1 deficiency, (ii) AR partial STAT1 deficiency, (iii) autosomal dominant (AD) STAT1 deficiency, and (iv) AD STAT1 gain of function (GOF), based on their mode of inheritance and function. Disease types (i, ii, and iii) are caused by STAT1 loss-of-function (LOF) mutations, whereas disease type (iv) is caused by STAT1 GOF mutations. Therefore, the functional analysis of mutations is necessary for the precise diagnosis. Graphical Abstract [ABSTRACT FROM AUTHOR]

The high-affinity IgE receptor, FcεRI, plays a key role in the antigen-induced mast cell activation. Regulations for FcεRI are not yet well understood. TAFA4 is a molecule derived from neuron tissues, and has immune regulation functions. This study aims to clarify the role of TAFA4 in the regulation of FcεRI expression in mast cells. Nasal secretions were collected from patients with allergic rhinitis (AR) and healthy control (HC) subjects. TAFA4 levels of nasal secretions were evaluated by ELISA. A mouse model AR was developed using ovalbumin as the specific antigen. Negative correlation between TAFA4 and tryptase levels in nasal secretions was observed. TAFA4 could suppress the antigen-related mast cell activation. TAFA4 modulated the transcription of Fcer1g (FcεRI γ gene) in mast cells. Signals from the TAFA4-PTEN-PU.1 axis restricted FcεRI expression in mast cells. Administration of TAFA4 attenuated experimental AR. TAFA4 suppressed the expression of FcεRI in mast cells of airway tissues. TAFA4 can down regulate the expression of FcεRI in mast cells to suppress experimental AR. The data suggest that TAFA4 has translation potential to be developed as an anti-allergy therapy. TAFA4 suppressed the expression of FceRI in mast cells of airway tissues. Signals from the TAFA4-PTEN-PU.1 axis restricted FceRI expression in mast cells. Administration of TAFA4 attenuated experimental AR. [ABSTRACT FROM AUTHOR]

Immune Check-Point Inhibitors (ICIs) have shown remarkable promise in treating tumors, including non-small cell lung cancer (NSCLC). Nevertheless, the treatment response rate is low. Studies have found that the high expression of exosomal PD-L1 is one of the reasons for the low treatment response. Therefore, this study focused on the relationship between the exosomal PD-L1 and the clinical response to immunotherapy in NSCLC patients to evaluate whether it could be used as a biomarker to predict the efficacy of ICIs. In this study, clinical information and blood samples of 149 NSCLC patients receiving ICIs were collected. The expression level of exosomal PD-L1 was detected by enzyme-linked immunosorbent assay method, and the relationship between exosomal PD-L1 and the efficacy of ICIs was explored. Overall, our study found that the expression level of exosomal PD-L1 was lower at pre-treatment, or the max fold increasing change higher at 3–6 weeks had a higher disease control rate and longer progression-free survival. It revealed that the exosomal PD-L1 was associated with the treatment response of patients using ICIs and provided a new tool for the evaluation of clinical efficacy of lung cancer immunotherapy. This study revealed that exosomal PD-L1 was associated with the treatment response of patients using ICIs. The level of pre-treatment and the maximum fold increasing change of exosomal PD-L1 stratified clinical responders and non-responders. [ABSTRACT FROM AUTHOR]

Summary Death rules our lives. In this short paper, we summarize new insights into molecular mechanisms of neurodegeneration. Here we review the most important processes of cell death: apoptosis and oncosis. We focus on autophagy, which is pivotal for neuronal homeostasis, in the context of neurodegeneration, infection and immunity. Its dysfunction has been linked to several neurodegenerative diseases such as Parkinson's, Huntington's and Alzheimer's diseases. Our understanding is still incomplete, but may highlight attractive new avenues for the development of treatment strategies to combat neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Pulmonary complications are common in patients with primary immune deficiency (PID). The aim of this study was to assess the usefulness of lung function tests (LFTs) in the management of these patients, and in particular to see if carbon monoxide transfer factor (TLCO) is needed in addition to spirometry. We studied 20 patients (11 female) with PID in a tertiary referral clinic, with a mean age of 47·6 years. Serial LFTs, spanning a mean of 101 months, were correlated with immunoglobulin levels and antibiotic usage. Seven patients showed a decline in forced expiratory volume in 1 second over the period of the study. An additional five patients showed a decline in TLCO. Of these 12 patients, two had no radiographic evidence of lung disease. Higher levels of immunoglobulin were associated with slower decline in LFTs ( P < 0·05). The analysis of antibiotic usage and LFTs failed to show a statistically significant effect, although there was a trend towards a slower rate of decline with greater use of antibiotics. LFTs decline slowly in patients with PID. Annual testing (both spirometry and transfer factor) is useful in the assessment of these patients, and should not be confined to those with radiological evidence of lung disease. [ABSTRACT FROM AUTHOR]

Tuberculosis and leprosy remain two ofthe world's most significant diseases. Immunity involves the activate of macrophage's by lymphokines but the details are unknown because there has been no objective assay for the relevant effector function using human pathogens. We previously reported the use of trotted-uracil uptake by surviving mycobacteria as a measure of the antimycobacterial effect of human monocytes. We describe here the use of a modification of this assay to measure control of the proliferation Mycobacterium tuberculosis in murine peritoneal macrophage's. A bacteriostatic effect can be induced in macrophage's infected with M. tuberculosis, by adding small numbers of Lye 1 T cells from in vitro lines derived from immunized mice. The phenomenon is dependent on compatibility at the I-A locus of the major histocompatibility complex (MHC) and mediated by soluble factors. Such T cells also recognise and activate macrophage's infected with other mycobacteria pathogens. Thus. T cells recognising shared mycobacteria antigens are active. The findings have implications for MHC linked susceptibility to mycobacterioses and the hypothesized ability of cross-reactive environmental mycobacteria to abrogate or preempt the protective efficacy of subsequent BCG vaccination. [ABSTRACT FROM AUTHOR]

The article informs that it is well established that hypogammaglobulinacmia is often found in Cushing's disease and after long-term steroid therapy. It has not been documented, however, whether or not all the-classes of immunoglobulins are reduced. Experiments on germ-free animals have clearly shown that exposure to antigens constitutes the major stimulus for normal immunoglobulin formation. The factors responsible for the remarkably constant immunoglobulin levels in healthy individuals are not yet understood, but a homeostatic mechanism can be postulated.

This article focuses on the specific activity of several enzymes of nucleotide metabolism in mouse spleen after immunization. After the injection of antigen into the mammalian host. a complex series of events begins which culminates in the synthesis of antibody. These events include the activation of latent information stored in the genomic of the organism for new RNA synthesis as well as an increase in the rate of DNA synthesis. To learn more of the early events alter exposure of the precursor cells to antigen, researchers determined the specific activities of several enzymes involved in nucleotide metabolism found after immunization in the spleens of mice.

Summary: Tuberculosis (TB) kills more people than any other single infectious disease globally. Despite decades of research, there is no vaccine to prevent TB transmission. Bacille Calmette–Guérin (BCG) vaccine, developed a century ago, is effective against childhood (disseminated and miliary) TB. However, its protective efficacy against pulmonary TB varies from 0 to 80% in different populations. One of the main reasons for the lack of an effective vaccine against TB is the lack of complete understanding about correlates of protective immunity on which to base vaccine design and development. However, some household contacts who are extensively exposed to Mtb infection remain persistently negative to tuberculin skin test and interferon‐gamma assay. These individuals, called 'resisters', clear Mtb infection early before the development of acquired immunity. The immunological basis of early Mtb clearance is yet to be established; however, innate lymphocytes such as monocytes/macrophages, dendritic cells, neutrophils and natural killer cells, and innate‐like T cells such as mucosal‐associated invariant T cells, invariant natural killer (NK) T cells and gamma‐delta (γδ) T cells, have been implicated in this early protection. In recent years, NK cells have attracted increasing attention because of their role in controlling Mtb infection. Emerging data from animal and epidemiological studies indicate that NK cells play a significant role in the fight against Mtb. NK cells express various surface markers to recognize and kill both Mtb and Mtb‐infected cells. This review presents recent advances in our understanding of NK cells in the fight against Mtb early during infection, with emphasis on cohort studies. [ABSTRACT FROM AUTHOR]

Five sera raised in rabbits against three strains of Streptococcus pyogenes (grown in semi-synthetic media) were shown by immunofluorescence to have antibodies reacting with both myocardial and conducting fibres. The pattern of staining on the conducting fibres was different to that on myocardial fibres and suggested the presence of larger amounts of cross-reacting antigen. Most work was done on ox heart, but the results were confirmed on human heart and rabbit heart. Absorption studies, carried out with three sera on ox heart only, showed that absorption with the homologous organism abolished in parallel the staining of both types of fibre. Absorption with heterologous organisms was less effective indicating the existence of more than one cardiac cross-reacting antigen. Absorption with myocardium, suggested that the conducting fibres contained streptococcal cross-reacting antigens additional to those found in the contractile [ABSTRACT FROM AUTHOR]

This article presents information on research papers related to immunology. In the paper "Modulatory Effects of Oestrogen on Immunological Responsiveness. Suppression of Tumour-Associated Immunity in Patients With Prostatic Cancer," the authors wish to point out that retrospective evaluation of the patients in this study has disclosed an effect of hormonal therapy, i.e. orchiectomy and or oestrogen on tumour-associated immunity independent of the effect of in vitro preincubation of patients' leucocytes with DES-P. While in "Migration of Sensitized Mouse Spleen Cells by Cell-Associated Transplantation Antigens: Effect of Method of Antigen Presentation," the authors wish to point out that they have been unable to repeat the MIF assay technique.

Summary: Natural killer (NK) cells play a major role in host immunity against leukaemia and lymphoma. However, clinical trials applying NK cells have not been as efficient as hoped for. Patients treated with rapidly accelerated fibrosarcoma (RAF) inhibitors exhibit increased tumour infiltration by immune cells, suggesting that a combination of RAF inhibitors with immunotherapy might be beneficial. As mitogen‐activated protein kinases (MAPKs) such as raf‐1 proto‐oncogene, serine/threonine kinase (CRAF) regulate NK cell functions, we performed an in‐vitro investigation on the potential of clinically relevant short‐acting tyrosine kinase inhibitors (TKIs) as potential adjuvants for NK cell therapy: NK cells from healthy human blood donors were thus treated with sorafenib, sunitinib or the pan‐RAF inhibitor ZM336372 during ex‐vivo expansion. Functional outcomes assessed after washout of the drugs included cytokine production, degranulation, cytotoxicity, apoptosis induction and signal transduction with/without target cell contact. Paradoxically, sorafenib enhanced NK cell effector functions in a time‐ and dose‐dependent manner by raising the steady‐state activation level. Of note, this did not lead to NK cell exhaustion, but enhanced activity against target cells such as K562 or Daudis mediated via the RAS/RAF/extracellular‐regulated kinase (ERK) pathway, but not via protein kinase B (AKT). Our data will pave the path to develop a rationale for the considered use of RAF inhibitors such as sorafenib for pre‐activation in NK cell‐based adoptive immune therapy. [ABSTRACT FROM AUTHOR]

Persistent inflammatory response in cystic fibrosis (CF) airways is believed to play a central role in the progression of lung damage. Anti-inflammatory treatment may slow lung disease progression, but adverse side effects have limited its use. Vitamin D has immunoregulatory properties. We randomized 16 CF patients to receive vitamin D2, vitamin D3 or to serve as controls, and investigated the effect of vitamin D supplementation on soluble immunological parameters, myeloid dendritic cells (mDCs) and T cell activation. Three months of vitamin D treatment were followed by two washout months. Vitamin D status at baseline was correlated negatively with haptoglobin, erythrocyte sedimentation rate and immunoglobulin A concentration. Total vitamin D dose per kg bodyweight correlated with the down-modulation of the co-stimulatory receptor CD86 on mDCs. Vitamin D treatment was associated with reduced CD279 (PD-1) expression on CD4+ and CD8+ T cells, as well as decreased frequency of CD8+ T cells co-expressing the activation markers CD38 and human leucocyte antigen D-related (HLA-DR) in a dose-dependent manner. There was a trend towards decreased mucosal-associated invariant T cells (MAIT) cell frequency in patients receiving vitamin D and free serum 25-hydroxyvitamin D (free-s25OHD) correlated positively with CD38 expression by these cells. At the end of intervention, the change in free-s25OHD was correlated negatively with the change in CD279 (PD-1) expression on MAIT cells. Collectively, these data indicate that vitamin D has robust pleiotropic immunomodulatory effects in CF. Larger studies are needed to explore the immunomodulatory treatment potential of vitamin D in CF in more detail. [ABSTRACT FROM AUTHOR]

Antiretroviral therapy (ART) only partially restores HIV-induced alterations in lymphocyte populations. We assessed B and T cell phenotypes in a cohort of children from a single centre in the United Kingdom with perinatally acquired HIV compared to healthy controls. The majority of HIV infected children (44 of 56) were on fully suppressive combination ART. Children with perinatally acquired HIV had significantly lower memory B and CD4+CD45RO+CXCR5+ [follicular T helper cell (Tfh)-like] T cell percentages. Detectable viraemia was associated with higher CD21- (activated and exhausted/tissue-like memory) B cells. A greater proportion of life spent on suppressive ART was associated with higher memory B cell percentages. These results suggest that early and sustained suppressive ART may preserve B and T cell phenotypes in perinatally acquired HIV and limit deficits in humoral immunity. A lower proportion of circulating Tfh-like cells in HIV infected children appears to be independent of HIV treatment history and ongoing HIV viraemia and warrants further investigation. [ABSTRACT FROM AUTHOR]

Toll-like receptors ( TLRs) are the best-studied family of pattern-recognition receptors ( PRRs), whose task is to rapidly recognize evolutionarily conserved structures on the invading microorganisms. Through binding to these patterns, TLRs trigger a number of proinflammatory and anti-microbial responses, playing a key role in the first line of defence against the pathogens also promoting adaptive immunity responses. Growing amounts of data suggest that single nucleotide polymorphisms ( SNPs) on the various human TLR proteins are associated with altered susceptibility to infection. This review summarizes the role of TLRs in innate immunity, their ligands and signalling and focuses on the TLR SNPs which have been linked to infectious disease susceptibility. [ABSTRACT FROM AUTHOR]

Numerous studies have suggested the importance of leptin against autoimmune diseases such as systemic lupus erythematosus ( SLE), multiple sclerosis ( MS) and psoriasis. To summarize our current understanding of the role of leptin in inflammatory responses and rheumatoid arthritis ( RA), a systematic review was conducted to assess the discrepancy of leptin in RA and its effect on immunity according to different studies. Recently, emerging data have indicated that leptin is involved in the pathological function of RA, which is common in autoimmune disorders. This review discusses the possible consequences of leptin levels in RA. Blocking the key signal pathways of leptin and inhibiting the leptin activity-like leptin antagonist may be a promising way for potential therapeutic treatment of RA at risk of detrimental effects. However, leptin was increased in patients with RA and may also regulate joint damage. Thus, more understanding of the mechanism of leptin in RA would be advantageous in the future. [ABSTRACT FROM AUTHOR]

Infection with many encephalitic viruses is associated with the induction of the proinflammatory cytokine interleukin (IL)-6. In some situations, induction of high levels of this cytokine is associated with a protective response, but in others it can be linked to tissue damage and disease. In the studies reported here, levels of serum IL-6 and virus-specific antibodies were measured on admission to hospital and correlated with clinical outcomes. Only some patients demonstrated raised levels of serum IL-6, and there was no correlation between high levels of this cytokine and either gender or the severity of clinical disease. A statistically significant association between raised IL-6 and age was observed, with all individuals below the age of 26 showing normal levels of serum IL-6, regardless of clinical presentation. Furthermore, not all patients had detectable levels of virus-specific serum immunoglobulin G (IgG) antibodies, but an inverse and statistically significant correlation between raised IL-6 levels and IgG titre was observed. Consequently, serum levels of IL-6 cannot be used as a reliable indicator of disease outcome. [ABSTRACT FROM AUTHOR]

Natural killer cells constitute a potent, rapid part of the innate immune response to infection or transformation, and also generate a link to priming of adaptive immunity. Their function can encompass direct cytotoxicity as well as the release of cytokines and chemokines. In humans, a major component of natural killer (NK) cell target recognition depends mainly on the surveillance of human leucocyte antigen (HLA) class I molecules by killer immunoglobulin-like receptors (KIR). Different KIR can transmit inhibitory or activatory signals to the cell, and effector function is considered to result from the balance of these contributing signals. The regulation of NK cell responses depends on a number of variables: KIR genotype, HLA genotype, heterozygosity versus homozygosity for these, whether there is cognate recognition between the HLA and KIR products carried by an individual, clonal variation between individual NK cells in KIR expression, and the specific modulation of HLA expression by infection, transformation or peptide binding. Different HLA/KIR genotypes can impart different thresholds of activation to the NK cell repertoire and such genotypic variation has been found to confer altered risk in a number of diseases including human immunodeficiency virus (HIV) susceptibility and progression, hepatitis C virus clearance, idiopathic bronchiectasis, autoimmunity and cancer. [ABSTRACT FROM AUTHOR]

Epidemiological data have indicated that some infections are associated with a low risk of allergic diseases, thus supporting the idea (hygiene hypothesis) that the microbial load is an important environmental factor conferring protection against the development of allergies. We set out to test the hygiene hypothesis in a unique epidemiological setting in two socio-economically and culturally markedly different, although genetically related, populations living in geographically adjacent areas. The study cohorts included 266 schoolchildren from the Karelian Republic in Russia and 266 schoolchildren from Finland. The levels of total IgE and allergen-specific IgE for birch, cat and egg albumen were measured. Microbial antibodies were analysed against enteroviruses (coxsackievirus B4), hepatitis A virus, Helicobacter pylori and Toxoplasma gondii. Although total IgE level was higher in Russian Karelian children compared to their Finnish peers, the prevalence of allergen-specific IgE was lower among Russian Karelian children. The prevalence of microbial antibodies was, in turn, significantly more frequent in the Karelian children, reflecting the conspicuous difference in socio-economic background factors. Microbial infections were associated with lower risk of allergic sensitization in Russian Karelian children, enterovirus showing the strongest protective effect in a multivariate model. The present findings support the idea that exposure to certain infections, particularly in childhood, may protect from the development of atopy. Enterovirus infections represent a new candidate to the list of markers of such a protective environment. However, possible causal relationship needs to be confirmed in further studies. [ABSTRACT FROM AUTHOR]

Edward Jenner's discovery of vaccination must rank as one of the most important medical advances of all time and is a prominent example of the power of rational enquiry being brought to bear during the Age of Enlightenment in 18th century Europe. In the modern era many millions of lives are saved each year by vaccines that work essentially on the same principles that were established by Edward Jenner more than 200 years ago. His country home in Berkeley, Gloucestershire, is where he carried out his work and where he spent most of his life. The building is now a museum in which the life and times of Jenner are commemorated including not only the discovery of smallpox vaccination but also his other important scientific contributions to natural history and medicine. The trustees of the Edward Jenner museum are committed to promoting the museum as a real and “virtual” educational centre that is both entertaining and informative. [ABSTRACT FROM AUTHOR]

The Toll-like receptor (TLR) family provide key components of mammalian immunity and are part of the earliest surveillance mechanisms responding to infection. Their activation triggers the innate immune response, and is crucial to the successful induction of Th1/Th2-phenotyped adaptive immunity. Innate immunity was long considered to be non-specific and somewhat simple compared to adaptive immunity, mediated via the engulfment and lysis of microbial pathogens by phagocytic cells such as macrophages and neutrophils, and involving no complex protein–protein interactions. The emergence of the TLR field has contributed to a revision of our understanding, and innate immunity is now viewed as a highly complex process, in line with adaptive immunity. This review will give a brief overview of our current knowledge of TLR biology, and will focus on TLRs as key components in complex networks that activate, integrate and select the appropriate innate and adaptive immune responses in the face of immunological danger. [ABSTRACT FROM AUTHOR]

Because primary immunodeficiencies (PID) are rare diseases, transnational studies are essential to maximize the scientific outcome and lead to improved diagnosis and therapy. Immunologists in Europe have united to determine the prevalence of PID in Europe and to establish and evaluate harmonized guidelines for the diagnosis and treatment of PID as well as to improve the awareness of PID in Europe. In order to achieve this aim we have developed an internet-based database for clinical and research data on patients with PID. This database forms the platform for studies of demographics, the development of new diagnostic and therapeutic strategies and the identification of novel disease-associated genes. The database is completely secure, while providing access to researchers via a standard browser using password and encrypted log-in sessions and conforms to all European and national ethics and data protection guidelines. So far 2386 patients have been documented by 35 documenting centres in 20 countries. Common variable immunodeficiency (CVID) is the most common entity, accounting for almost 30% of all entries. First statistical analyses on the quality of life of patients show the advantages of immunoglobulin replacement therapy, at the same time revealing a mean diagnostic delay of over 4 years. First studies on specific questions on selected PID are now under way. The platform of this database can be used for any type of medical condition. [ABSTRACT FROM AUTHOR]

Toll-like receptors (TLRs) respond to pathogens to initiate the innate immune response and direct adaptive immunity, and evidence to date suggests that they have a role in the detection of viruses. Many viral macromolecules have been shown to activate anti-viral signalling pathways via TLRs, leading to the induction of cytokines and interferons, while viruses also have means of not only evading detection by TLRs, but also of subverting these receptors for their own purposes. This review discusses the role of TLRs in the context of other known viral detection systems, and examines some of the often surprising results from studies using mice deficient in TLRs and their adaptors, in an attempt to unravel the particular contribution of TLRs to anti-viral immunity. [ABSTRACT FROM AUTHOR]

The world is confronted with major tuberculosis (TB) outbreaks at a time when the protection of bacillus Calmette–Guérin (BCG) vaccine has become inconsistent and controversial. Major TB outbreaks are caused by a group of genetically similar strains of Mycobacterium tuberculosis ( Mtb) strains, including the Beijing family genotypes. The Beijing family genotypes exhibit important pathogenic features such high virulence, multi-drug resistance and exogenous reinfection. These family strains have developed mechanisms that modulate/suppress immune responses by the host, such as inhibition of apoptosis of infected macrophages, diminished production of interleukin (IL)-2, interferon (IFN)-γ, tumour necrosis factor (TNF)-α and elevated levels of IL-10 and IL-18. They demonstrate distinct expression of proteins, such as several species of α-crystallin (a known Mtb virulence factor), but decreased expression of some antigens such as heat shock protein of 65 kDa, phosphate transport subunit S and a 47-kDa protein. In addition, the Beijing family strains specifically produce a highly bioactive lipid (a polyketide synthase)-derived phenolic glycolipid. This altered expression of proteins/glycolipids may be important factors underlying the success of the Beijing family strains. The Beijing family strains are speculated to have originated from South-east Asia, where BCG vaccination has been used for more than 60 years. The hypothesis that mass BCG vaccination may have been a selective factor that favoured genotypic and phenotypic characteristic acquired by the Beijing family strains is discussed. [ABSTRACT FROM AUTHOR]

Vitamin A supplementation reduces child mortality in populations at risk of vitamin A deficiency and may also reduce maternal mortality. One possible explanation for this is that vitamin A deficiency is associated with altered immune function and cytokine dysregulation. Vitamin A deficiency in pregnancy may thus compound the pregnancy-associated bias of cellular immune responses towards Th-2-like responses and exacerbate susceptibility to intracellular pathogens. We assessed mitogen and antigen-induced cytokine responses during pregnancy and lactation in Ghanaian primigravidae receiving either vitamin A supplementation or placebo. This was a double-blind, randomized, placebo-controlled trial of weekly vitamin A supplementation in pregnant and lactating women. Pregnancy compared to postpartum was associated with a suppression of cytokine responses, in particular of the proinflammatory cytokines interferon (IFN)-γ and tumour necrosis factor (TNF)-α. Mitogen-induced TNF-α responses were associated with a decreased risk of peripheral parasitaemia during pregnancy. Furthermore, vitamin A supplementation was significantly associated with an increased ratio of mitogen-induced proinflammatory cytokine (IFN-γ) to anti-inflammatory cytokine (IL-10) during pregnancy and in the postpartum period. The results of this study indicate that suppression of proinflammatory type 1 immune responses and hence immunity to intracellular infections, resulting from the combined effects of pregnancy and vitamin A deficiency, might be ameliorated by vitamin A supplementation. [ABSTRACT FROM AUTHOR]

Human visceral leishmaniasis (VL), also known as kala azar (KA) in India, is a systemic progressive disease caused by Leishmania donovani. In VL, Th1 responses correlate with recovery from and resistance to disease and resolution of infection results in lifelong immunity against the disease. However, recent data suggest an important role for interleukin (IL)-10 in maintaining the resistant state. We evaluated whole cell extract (WE) and 11 antigenic fractions [F1–F11, molecular weight (MW) range of 139–24·2 kDa] from L. donovani (2001 strain, a fresh field isolate from Bihar), for their ability to induce in vitro T cell proliferation and production of interferon (IFN)-γ, interleukin (IL)-12, IL-10 and IL-4 by peripheral blood mononuclear cells (PBMCs) of exposed immune individuals (14 patients with history of VL, 10 household endemic contacts) and 20 non-endemic healthy controls. Twenty-one of 24 exposed individuals and no healthy controls showed proliferative response to WE. Whole-extract activated IFN-γ, IL-12, IL-10 levels were higher in the exposed group than in controls; IL-4 was not detectable in any of the samples. Among 21 responders to WE, frequent proliferative responses were seen to fractions F1–F4 (MW > 64·2 kDa) and none to fractions F5–F11; fractions F1–F11 stimulated comparable levels of IFN-γ and IL-12 while IL-10 levels were higher in response to F5–F11 compared to F1–F4. These data demonstrate the presence of immunostimulatory antigens in the high MW fractions of whole L. donovani antigen. However, these fractions do not stimulate a Th1 response and produce variable amounts of IFN-γ and the regulatory cytokine, IL-10. Hence, these high MW immunostimulatory fractions need to be evaluated in greater depth for their possible role as protective antigens. [ABSTRACT FROM AUTHOR]

The incidence of mycobacterial diseases is high and the efficacy of Bacillus Calmette Guérin (BCG) is low in most areas of the world where chronic worm infections are common. However, if and how concurrent worm infections could affect immunity to mycobacterial infections has not been elucidated. In this study we investigated whether infection of mice withSchistosoma mansonicould affect the ability of the animals to controlMycobacterium bovisBCG infection and the immune response to mycobacterial antigens. BALB/c mice subclinically infected withS. mansoniwere challenged withM. bovisBCG via the intravenous route. The ability of the animals to contain the replication ofM. bovisBCG in their organs, lung pathology as well as thein vitromycobacterial and worm antigen induced immune responses were evaluated. The results showed thatS. mansonicoinfected mice had significantly higher levels of BCG bacilli in their organs and sustained greater lung pathology compared to Schistosoma uninfected controls. Moreover, Schistosoma infected mice show depressed mycobacterial antigen specific Th1 type responses. This is an indication that chronic worm infection could affect resistance/susceptibility to mycobacterial infections by impairing mycobacteria antigen specific Th1 type responses. This finding is potentially important in the control of TB in helminth endemic parts of the world. [ABSTRACT FROM AUTHOR]

Editorial. Reports that nasal vaccination induces protective immunity without immunopathology. Findings of studies on the mucosal associated lymphoid tissue (MALT); Mechanisms dictating lymphocyte migration patterns through MALT; Regional specialization in the respiratory tract.

Expression of the erythrocyte complement receptor (C3bR = CR1 = CD35) and its genomic polymorphism (HindIII RFLP) was studied in a group of 80 patients with IDDM, 31 healthy siblings and 101 healthy blood donors. Defective CR1 expression was found in 26% of the patients with IDDM compared with 9% of the controls (P<0.05) and 0% of the siblings. The CR1 gene polymorphism of the IDDM patients did not significantly differ from that of the controls. The presence of a 6.9 kb (L) CR1 gene fragment was associated with a low CR1 expression in the patients (P<0.05) and especially in the controls (P<0.001). No significant association was found between the presence or absence of the HLA risk antigens for IDDM and CR1 expression. The results confirm that erythrocyte CR1 expression is genetically determined, but the CR1 deficiency associated with IDDM seems to be an acquired rather than a genetic phenomenon. [ABSTRACT FROM AUTHOR]

In order to define the optimal conditions for detection of microbial antigens in urine, urinary HBsAg excreted during hepatitis B was chosen as a model. Using commercial kits, which mainly involve anti- discontinuous epitopes, we found urinary HBsAg in only 50% of patients with HBsAg in their sera. In contrast, with an inhibition method involving a monoclonal antibody recognizing a continuous epitope, urinary HBsAg was found in 100% of these patients. Structural analysis of HBsAg showed that urinary HBsAg is denatured; it can escape detection by commercial kits well fitted for detection of native serum HBsAg. General implications for the revelation of urinary microbial antigens are discussed. [ABSTRACT FROM AUTHOR]

The NOD mouse is a model of human juvenile type I diabetes mellitus. As in humans and in the BB rat model, the development of diabetes in NOD mice is accompanied by evident manifestations of cell-mediated and humoral autoimmunity. Beside autoantibodies directed at putative islet cell antigens, NOD sera contain antibodies with specificity for lymphocyte cell-surface determinants. Here we demonstrate that these anti-lymphocyte antibodies have the same characteristics of target cell specificity, of isotype. and of temperature reactivity, as do natural thymocytotoxic autoantibodies (NTA) from lupic NZB mice, or from mice undergoing polyclonal B cell activation. We also demonstrate that the thymocytotoxic activity of NOD sera is not due to cross-reactive anti-insulin antibodies. Biochemical characterization of the determinants recognized by these anti-lymphocyte antibodies reveals two membrane-associated proteins of 28 and 33 kD, partially similar to the two peptides recognized by NTA from NZB mice (30 and 33 kD), Altogether, these results suggest that NOD mice develop manifestations of polyclonal B cell activation similar to those observed in lupus-prone mice. The relationship of these anomalies with the organ-specific pancreatic disease remains to be properly evaluated. [ABSTRACT FROM AUTHOR]

Recently we reported on the participation of dietary antigens in the pathogenesis of IgA nephropathy. Particularly, the glomerular deposition of dietary antigens (casein, soybean protein, rice protein) was observed in some cases with IgA nephropathy. It is known that human urinary pepsin (HUP) prepared from the urine of a healthy adult acts as an immune complexase at neutral pH. In this study, the effects of incubation with HUP on the glomerular deposition of dietary antigens was investigated by an immunofluorescence technique In 48 patients with IgA nephropathy, four patients with Henoch Schöntein purpura nephritis and 69 with other glomcrulonephrltides. In 33 cases (68.8%) soybean protein and in 12 (25.0%) casein was found in biopsies of patients with IgA nephropathy. After a 3-day incubation with HUP there was no change in the deposition of IgA in 12 cases, a decrease in 22 and complete elimination in 14 cases. The deposits of soybean protein increased in 12 cases, did not change in 20, decreased or was abolished in five and was positively converted in 11. Exceptionally, in five patients treated with HUP, the deposition of soybean protein appeared concomitantly with the disappearance of IgA deposits. Such a concomitance did not occur either in other glomerulonephritides or in studies of other dietary antigens. Thus it appears that soybean protein may be deposited in the glomerular mesangium as an antigen in some patients with IgA nephropathy. [ABSTRACT FROM AUTHOR]

The cytolytic capacity of mycobacterial antigen-stimulated peripheral blood mononuclear cells. from healthy Mantoux-positive volunteers and from patients with tuberculosis was investigated. Polyclonal T cell lines induced by 7 days of stimulation in vitro with PPI) or a sonicate of Mycobacteriurn tuberculosis lysed both autologous macrophages and Epstein-Barr virus (9W) transformed B cell lines which had been pulsed with mycobacterial antigens. to a greater extent than unpulsed target cells or target cells pulsed with an irrelevant antigen (streptokinase/streptodornase). The killing of mycobacterial antigen-pulsed macrophages and NV-transformed B cell line targets was inhibited by monoclonal antibodies to MHC class II antigens hut not by antibodies directed against MHC class I antigens. PPI)-pulsed EBV-transformed lympboblastoid cell lines (IX'L) competitively inhibited the killing of mycobacterial antigen-pulsed macrophages. whereas natural killer (NK) sensitive K562 cells (with or without antigen pulsing) did not inhibit mycobacterial antigen-dependent cytolysis of macrophages. Patients with tuberculosis showed a spectrum of mycobacterial antigen-induced cytolytic capacity. Those with extensive tissue necrosis (e.g. cavitatory pulmonary tuberculosis or caseous. extrathoracic tuberculosis) had high levels while patients with disseminated (miliary) tuberculosis or disease refractory to treatment showed little evidence of mycobacterial antigen induced cytotoxicity. Th ability of mycobacterial antigen- stimulated lymphoblasts to kill specific antigen-pulsed autologous macrophages was not significantly different between healthy donors and patients with tuberculosis. However, the `mycobacterial antigen-specific' component of this cytolysis was significantly deficient (P<0.01) in patients. We conclude that mycobacterial antigen-specific cytotoxic 1' cell responses may play a significant part in the immune response to mycobacterial infection. [ABSTRACT FROM AUTHOR]

The cellular control of antibody affinity maturation has been studied in mice genetically selected for their failure to demonstrate an increase in affinity following immunization (low-affinity N/M mice). Depletion of CD8+ cells In low N/M mice by thymectomy and/or anti-CD8 antibody treatment resulted in these animals acquiring the ability to mount an anti-DNP response of progressively increasing affinity. This indicates that CD8+ cells play an important regulatory role in the cellular interactions underlying the process of affinity maturation. In addition, evidence is presented which suggests that the route of immunization may also be critical in determining the affinity of antibody produced. [ABSTRACT FROM AUTHOR]

To identify antigens that could be specifically associated with tuberculosis infection, the antibody response to Mycobacterium tuberculosis antigens of patients with pulmonary tuberculosis and of healthy individuals were compared by immunoblot. In healthy individuals, scrum antibodies were found in the majority of cases. Bands of 60 and 32-31 kilodaltons (kD) were the antigens more frequently recognized by antibodies of normal sera (55.8 and 64.7%, respectively). In patients with pulmonary tuberculosis, the number and intensity of the developed antigen bands were much higher than in normal individuals. Antigens reacting preferentially with tuberculosis sera were also identified. Furthermore, a unique disease-associated protein antigen or 38 kD was found to react with 57% of patients' sera but with none of the controls. This antigen was isolated by elution from nitrocellulose membranes and tested as an ELISA reagent in the serodiagnosis of pulmonary tuberculosis. A specificity of 0.96 and sensitivity of 0.68 were obtained. [ABSTRACT FROM AUTHOR]

Mice genetically selected for the production of either high- or low-affinity antibody were led on diets sufficient or deficient in zinc. Thc effect of zinc deficiency on immune responses in these animals was analysed in terms of cell-mediated responses and the levels and affinity of antibody produced in response to immunization with T-dependent and T-independent antigens. In comparison with animals fed zinc-containing diets, mice fed zinc-deficient diets had reduced numbers of T cells and T- cell subsets, reduced proliferation to mitogens and specific antigen, and a decreased production of interleukin 2 (IL-2). but the number and affinity of IL-2 receptors were not affected. Furthermore, zinc-deficient animals produced reduced levels of antibody to the T-dependent antigen DNP-human serum albumin, but the affinity of this antibody was significantly elevated compared with that produced by zinc-sufficient animals, However, zinc deficiency had no effect on the levels and affinity of antibody produced to the T-independent antigen DNP-ficoll. [ABSTRACT FROM AUTHOR]

The effect of interleukin 2 (IL-2) on cord blood mononuclear cells (CBMC) was studied, with special reference to B cell function. The study shows that CBMCs proliferate in response to recombinant interleukin 2 (rIL-2) without in-vitro preactivation. The response was also detected when whole blood cultures were used. CBMCs not preactivated in vitro proliferated in response to rIL-2 even after T cell and monocyte depletion. Thus, rIL-2 affects both non-T cells and T cells of newborns without preactivation in vitro. IL-2 receptors on unstimulated CBMCs appear to be distinct from Tac antigen, as the mean number of Tac antigen-positive cells among CBMCs was only 0.8%. Furthermore, rIL-2 inhibited PWM-induced proliferation and the response was more prominent in newborns than in adults. Thus, rIL-2 seems to cause a higher increase of suppressor cell function in CBMCs than in adult peripheral blood mononuclear cells. Neither rIL-2 nor Staphylococcus aureus Cowan 1 (SAC) stimulated any IgM synthesis, but a dose-dependent IgM synthesis was obtained by combining SAC and rIL-2. Alone, however, rIL-2 appears to be an insufficient factor to induce differentiation of SAC-activated cord blood B cells, as no IgM production in response to rIL-2 occurred in T cell and monocyte-depleted cell populations. The results of this study suggest both increased suppressor cell function and intrinsic B cell deficiency as causes of a weak humoral immune response in newborns. [ABSTRACT FROM AUTHOR]

Sera from 23 children with autoimmune chronic active hepatitis and positive for anti-liver-kidney-microsome antibody (LKMA), as defined by immunofluorescence, were analysed by Western blot (WB) and two-dimensional gel electrophoresis using rat liver microsomes as antigen, and by WB and dot-blot analysis with rat liver microsomal subfractions. Western blot analysis showed three patterns of reactivity: 13 sera recognized a 50 kD polypeptide, six sera a 66 kD polypeptide and four sera both of them. Two-dimensional gel electrophoresis, WB, and dot-blot analysis showed the 66 kD antigen to have a pI of 5.4 and to be located in the smooth domain of the endoplasmic reticulum. Western blot analysis using monospecific antisera against human IgG subclasses showed the LKMA directed against the 66 kD antigen to be mainly of the IgG1 subclass. These results indicate that LKMA associated with a subgroup of autoimmune hepatitis of children react with at least two different microsomal antigens in rat liver: (1) the 50 kD polypeptide, recently shown to be a cytochrome P-450 of the IID subfamily, and (2) a new antigen of 66 kD, the location of which suggests it may also be part of the mono-oxygenase complex. [ABSTRACT FROM AUTHOR]

The potential of a panel of synthetic HBsAg peptides as components of a synthetic hepatitis B vaccine was assessed. Each was used in turn as probes lo analyse human immune responses to a licensed plasma-derived HBV vaccine. Both humoral and cellular responses were analysed with synthetic peptides representing residues 124-147 of the surface antigen of the virus (HBsAg) and residues 126- 140 of the pre-S2 region. Antibody levels and affinities were assessed In radioimmunoassays with synthetic linear and cyclical forms of surface antigen peptides 124-137 and 139-147, with the gp30p25 polypeptide complex of HBsAg and with the linear pre-S2 peptide 126-140. Levels and affinities of antibodies lo the antigens increased with time during immunization. However, antibodies binding the cyclical peptide representing amino acids 139 to 147 (C139) were present at higher levels and had higher affinities than were antibodies binding the other peptides, indicating that C139 more closely approximates a domain on the native antigen than do the other peptides. No humoral responses were measured with the pre-S2 peptide. Cellular responses were assessed by in vitro stimulation of peripheral blood lymphocytes by HBsAg and by the synthetic peptides. All vaccine recipients had demonstrable lymphocyte responsiveness to HBsAg after both second and third doses of the vaccine. Of the S and pre-S peptides used, only L124 failed lo induce lymphocyte stimulation in all recipients. However, there were individual variations in both the lime of initial responsiveness to peptides and in the level and time of maximal stimulation. Stimulation by native HBsAg particles, which corresponded to the appearance of anti-HBs antibody, preceded that observed using synthetic peptides. In all recipients, maximum stimulation indices with HBsAg were significantly higher than those observed with the peptides. In contrast to the absence of pre-S2 antibody, the lymphocytes from all recipients showed positive stimulation in response to the peptide representing residues 126-140 of the pre-S2 region. None of these individuals had antibodies to pre-S or an HB core peptide sequence nor did their lymphocytes respond to a synthetic peptide representing an HB core sequence. [ABSTRACT FROM AUTHOR]

The regional lymph nodes of mice show increased IL-2 activated killer (LAK) activity following immunization with the contact sensitizing agents, 'oxazolone' and picryl chloride. This is best elicited with 500 u/ml human recombinant lL-2 and can be demonstrated with both YAC-1 and K562 targets. There is also a lesser increase in NK, activity. [ABSTRACT FROM AUTHOR]

Three monoclonal antibodies (MoAb), named 8A. 8F6 and 62B1. reacting with plasma cell-associated antigens. were characterized. 8A was found to he positive throughout the B cell lineage maturation steps from the immature B-committed CD10+ cell to the plasma cells. 8F6 and 62B1 reactivity is restricted to more mature cells and related lymphoid malignancies. In particular 62B1 appears to be limited to hairy cells and plasma cells. The results show that it is possible to obtain reagents reacting with plasma cells by immunizing mice with cells derived from human multiple myclomas. Furthermore, the obtained results suggest that it is possible to elicit antibodies against antigens which are present throughout all the differentiation steps of the B cell lineage. These new MoAb could help in elucidating the phenotype of the plasma cells and the relationships of multiple myclomas with other B cell proliferative disorders. [ABSTRACT FROM AUTHOR]