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1: Curr Med Chem. 2007;14(10):1075-85.
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Early-life immune insult and developmental immunotoxicity (DIT)-associated diseases: potential of herbal- and fungal-derived medicinals.
Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853 USA. rrd1@cornell.edu
Developmental immunotoxicity (DIT) is increasingly recognized as a significant risk factor contributing to later life immune dysfunction as well chronic disease. In fact, recent increases in the incidence of asthma, allergic disease, autoimmunity and childhood infections maybe linked to problematic early life environmental exposures. The immune system of the non-adult is particularly susceptible to environmental influences whether from prenatal exposure to environmental toxins, maternally-administered drugs, infections or from postnatal exposure to toxicants, infectious agents and allergens. Additionally, adult-exposure models of immunotoxicity have been largely ineffective in predicting DIT risk. DIT-induced immune dysfunction can take many forms depending upon the environmental factor(s) involved and the precise developmental timing of exposure. If one examines the spectrum of published studies, a predominant phenotype has emerged that includes: Th balance skewing toward Th2, suppression of Th1 function, regulatory T cell function alteration, T cell repertoire abnormalities, problematic regulation of inflammatory cell function leading to hyperinflammatory responses and perturbation of cytokine networks. Early-life immune insult can also result in damage to the neurological and cardiovascular systems as well as endocrine and reproductive organs. Most therapeutic approaches to date have addressed the disease outcomes of DIT (e.g. asthma, allergy, autoimmunity, infections, and cancer) rather than focusing on the underlying immune dysfunction that creates the increased disease risk. While identification and prevention of problematic early life exposures is the best protection against DIT, this is not always possible. Therefore, identification of potential therapeutic approaches to reverse the immune dysfunction in the juvenile or adult is needed. In this review, we consider potential phytotherapeutic candidates among herbal- and fungal-derived medicinals for possible postnatal correction of the most predominant DIT-induced immune problems.
PMID: 17456021 [PubMed – indexed for MEDLINE]
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1: Folia Microbiol (Praha). 1998;43(5):545-50.
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Autoimmunity, immunodeficiency and mucosal infections: chronic intestinal inflammation as a sensitive indicator of immunoregulatory defects in response to normal luminal microflora.
Division of Immunology and Gnotobiology, Academy of Sciences of the Czech Republic, Prague.
Despite the fact that target antigens and the genetic basis of several autoimmune diseases are now better understood, the initial events leading to a loss of tolerance towards self-components remain unknown. One of the most attractive explanations for autoimmune phenomena involves various infections as possible natural events capable of initiating the process in genetically predisposed individuals. The most accepted explanation of how infection causes autoimmunity is based on the concept of "molecular mimicry" (similarity between the epitopes of an autoantigen and the epitopes in the environmental antigen). Infectious stimuli may also participate in the development of autoimmunity by inducing an increased expression of stress proteins (hsp), chaperones and transplantation antigens, which leads to abnormal processing and presentation of self antigens. Superantigens are considered to be one of the most effective bacterial components to induce inflammatory reactions and to take part in the development and course of autoimmune mechanisms. It has long been known that defects in the host defense mechanism render the individual susceptible to infections caused by certain microorganisms. Impaired exclusion of microbial antigens can lead to chronic immunological activation which can affect the tolerance to self components. Defects in certain components of the immune system are associated with a higher risk of a development of autoimmune disease. The use of animal models for the studies of human diseases with immunological pathogenesis has provided new insights into the influence of immunoregulatory factors and the lymphocyte subsets involved in the development of disease. One of the most striking conclusion arising from work with genetically engineered immunodeficient mouse models is the existence of a high level of redundancy of the components of the immune system. However, when genes encoding molecules involved in T cell immunoregulatory functions are deleted, spontaneous chronic inflammation of the gut mucosa (similar to human inflammatory bowel disease) develops. Surprisingly, when such immunocompromised animals were placed into germfree environment, intestinal inflammation did not develop. Impairment of the mucosal immune response to the normal bacterial flora has been proposed to play a crucial role in the pathogenesis of chronic intestinal inflammation. The use of immunodeficient models colonized with defined microflora for the analysis of immune reactivity will shed light on the mode of action of different immunologically important molecules responsible for the delicate balance between luminal commensals, nonspecific and specific components of the mucosal immune system.
PMID: 9821323 [PubMed – indexed for MEDLINE]