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Immunoregulatory Mechanisms (immunoregulatory + mechanism)
Selected AbstractsImmune modulation by helminthic infections: worms and viral infectionsPARASITE IMMUNOLOGY, Issue 10 2006S. M. KAMAL SUMMARY Helminthic infections occur worldwide, especially in developing countries. About one-quarter of the world's population, 1·5 billion, are infected with one or more of the major soil-transmitted helminths, including hookworms, ascarids, and whipworms. Schistosomes infect more than 200 million people worldwide with 600 million at risk in 74 countries. The interaction between helminths and the host's immune system provokes particular immunomodulatory and immunoregulatory mechanisms that ensure their survival in the host for years. However, these changes might impair the immunological response to bystander bacterial, viral, and protozoal pathogens and to vaccination. Modulation of the immune system by infection with helminthic parasites is proposed to reduce the levels of allergic responses and to protect against inflammatory bowel disease. In this review, we summarize the immunological milieu associated with helminthic infections and its impact on viral infections, mainly hepatitis B virus, hepatitis C virus, and human immunodeficiency virus in humans and experimental animals. [source] REVIEW ARTICLE: Maternal Immune Responses to Trophoblast: The Contribution of the Horse to Pregnancy ImmunologyAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 4 2010Leela E. Noronha Citation Noronha LE, Antczak DF. Maternal immune responses to trophoblast: the contribution of the horse to pregnancy immunology. Am J Reprod Immunol 2010 The horse has proven to be a distinctively informative species in the study of pregnancy immunology for several reasons. First, unique aspects of the anatomy and physiology of the equine conceptus facilitate approaches that are not possible in other model organisms, such as non-surgical recovery of early stage embryos and conceptuses and isolation of pure trophoblast cell populations. Second, pregnant mares make strong cytotoxic antibody responses to paternal major histocompatibility complex class I antigens expressed by the chorionic girdle cells, permitting detailed evaluation of the antigenicity of these invasive trophoblasts and how they affect the maternal immune system. Third, there is abundant evidence for local maternal cellular immune responses to the invading trophoblasts in the pregnant mare. The survival of the equine fetus in the face of strong maternal immune responses highlights the complex immunoregulatory mechanisms that result in materno,fetal tolerance. Finally, the parallels between human and horse trophoblast cell types, their gene expression, and function make the study of equine pregnancy highly relevant to human health. Here, we review the most pertinent aspects of equine reproductive immunology and how studies of the pregnant mare have contributed to our understanding of maternal acceptance of the allogeneic fetus. [source] History and Update on Host Defense Against Vaginal CandidiasisAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2007Paul L. Fidel Jr Vulvovaginal candidiasis (VVC), caused by Candida albicans, remains a significant problem in women of childbearing age. While cell-mediated immunity is considered the predominant host defense mechanism against mucosal candidal infections, two decades of research from animal models and clinical studies have revealed a lack of a protective role for adaptive immunity against VVC caused by putative immunoregulatory mechanisms. Moreover, natural protective mechanisms and factors associated with susceptibility to infection have remained elusive. That is until recently, when through a live challenge model in humans, it was revealed that protection against vaginitis coincides with a non-inflammatory innate presence, whereas symptomatic infection correlates with a neutrophil infiltrate in the vaginal lumen and elevated fungal burden. Thus, instead of VVC being caused by a putative deficient adaptive immune response, it is now being considered that symptomatic vaginitis is caused by an aggressive innate response. [source] Too clean, or not too clean: the Hygiene Hypothesis and home hygieneCLINICAL & EXPERIMENTAL ALLERGY, Issue 4 2006S. F. Bloomfield Summary The ,hygiene hypothesis' as originally formulated by Strachan, proposes that a cause of the recent rapid rise in atopic disorders could be a lower incidence of infection in early childhood, transmitted by unhygienic contact with older siblings. Use of the term ,hygiene hypothesis' has led to several interpretations, some of which are not supported by a broader survey of the evidence. The increase in allergic disorders does not correlate with the decrease in infection with pathogenic organisms, nor can it be explained by changes in domestic hygiene. A consensus is beginning to develop round the view that more fundamental changes in lifestyle have led to decreased exposure to certain microbial or other species, such as helminths, that are important for the development of immunoregulatory mechanisms. Although this review concludes that the relationship of the hypothesis to hygiene practice is not proven, it lends strong support to initiatives seeking to improve hygiene practice. It would however be helpful if the hypothesis were renamed, e.g. as the ,microbial exposure' hypothesis, or ,microbial deprivation' hypothesis, as proposed for instance by Bjorksten. Avoiding the term ,hygiene' would help focus attention on determining the true impact of microbes on atopic diseases, while minimizing risks of discouraging good hygiene practice. [source] Wasp venom immunotherapy induces a shift from IL-4-producing towards interferon-gamma-producing CD4+ and CD8+ T lymphocytesCLINICAL & EXPERIMENTAL ALLERGY, Issue 5 2001A. J. Schuerwegh Background Venom immunotherapy (VIT) has proven to be very effective in hymenoptera venom anaphylaxis. However, the underlying immunoregulatory mechanisms of venom immunotherapy remain poorly understood. Recent studies measured the total amount of cytokine in culture supernatans, suggesting a shift in cytokine production from Th2 to a Th1 cytokine profile during VIT. We wanted to examine the contribution of specific T lymphocyte subpopulations, which is impossible using an extracellular method to determine cytokines in supernatants. Objective The present study was designed to evaluate the effect of VIT on the percentages of type 1 (IL-2, interferon-gamma (IFN-,)) and type 2 (IL-4) CD4+ and CD8+ T lymphocytes of patients with wasp venom anaphylaxis during immunotherapy. Methods Peripheral blood mononuclear cells of 20 individuals with a history of wasp sting anaphylaxis and a positive serum wasp venom specific IgE were isolated and in vitro stimulated with phorbol-12-myristate-13-acetate and ionomycin before VIT, at the end of a 5-day semirush VIT and at 6 months during VIT. Three-colour flow cytometric analysis was used for intracellular cytokine (IL-2, IFN-,, IL-4) detection in CD4+ (CD3+CD8,) T lymphocytes and CD8+ (CD3+CD8+) T lymphocytes. Results At the end of a 5-day semirush VIT, there was a significant decrease in percentage of IL-4-producing CD4+ and CD8+ T cells, compared with cytokine-producing cells before VIT (P = 0.0002 and 0.004). After 6 months of VIT, patients showed an increased number of IL-2-producing stimulated CD4+ and CD8+ lymphocytes compared with values before VIT (P = 0.002 and P = 0.0003). A higher amount of IFN-,-producing stimulated CD4+ and CD8+ cells was found after 6 months of VIT (P = 0.001 and P = 0.0006). There was no correlation between cytokine-producing cells and specific IgE for wasp. Conclusion Venom immunotherapy induced a shift from IL-4-producing towards IFN-,-producing CD4+ as well as CD8+ T lymphocytes. [source] | ||||||||||