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Innate Immune Mechanisms (innate + immune_mechanism)

Distribution by Scientific Domains

Medical Sciences	75%

Selected Abstracts

Resistance to chytridiomycosis varies among amphibian species and is correlated with skin peptide defenses

ANIMAL CONSERVATION, Issue 4 2007
D. C. Woodhams
Abstract Innate immune mechanisms of defense are especially important to ectothermic vertebrates in which adaptive immune responses may be slow to develop. One innate defense in amphibian skin is the release of abundant quantities of antimicrobial peptides. Chytridiomycosis is an emerging infectious disease of amphibians caused by the skin fungus, Batrachochytrium dendrobatidis. Susceptibility to chytridiomycosis varies among species, and mechanisms of disease resistance are not well understood. Previously, we have shown that Australian and Panamanian amphibian species that possess skin peptides that effectively inhibit the growth of B. dendrobatidis in vitro tend to survive better in the wild or are predicted to survive the first encounter with this lethal pathogen. For most species, it has been difficult to experimentally infect individuals with B. dendrobatidis and directly evaluate both survival and antimicrobial peptide defenses. Here, we demonstrate differences in susceptibility to chytridiomycosis among four Australian species (Litoria caerulea, Litoria chloris, Mixophyes fasciolatus and Limnodynastes tasmaniensis) after experimental infection with B. dendrobatidis, and show that the survival rate increases with the in vitro effectiveness of the skin peptides. We also observed that circulating granulocyte, but not lymphocyte, counts differed between infected and uninfected Lit. chloris. This suggests that innate granulocyte defenses may be activated by pathogen exposure. Taken together, our data suggest that multiple innate defense mechanisms are involved in resistance to chytridiomycosis, and the efficacy of these defenses varies by amphibian species. [source]

A review on the interactions between gut microbiota and innate immunity of fish

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2008
Geovanny D. Gómez
Abstract Although fish immunology has progressed in the last few years, the contribution of the normal endogenous microbiota to the overall health status has been so far underestimated. In this context, the establishment of a normal or protective microbiota constitutes a key component to maintain good health, through competitive exclusion mechanisms, and has implications for the development and maturation of the immune system. The normal microbiota influences the innate immune system, which is of vital importance for the disease resistance of fish and is divided into physical barriers, humoral and cellular components. Innate humoral parameters include antimicrobial peptides, lysozyme, complement components, transferrin, pentraxins, lectins, antiproteases and natural antibodies, whereas nonspecific cytotoxic cells and phagocytes (monocytes/macrophages and neutrophils) constitute innate cellular immune effectors. Cytokines are an integral component of the adaptive and innate immune response, particularly IL-1,, interferon, tumor necrosis factor-,, transforming growth factor-, and several chemokines regulate innate immunity. This review covers the innate immune mechanisms of protection against pathogens, in relation with the installation and composition of the normal endogenous microbiota in fish and its role on health. Knowledge of such interaction may offer novel and useful means designing adequate therapeutic strategies for disease prevention and treatment. [source]

REVIEW ARTICLE: HIV Infection in the Female Genital Tract: Discrete Influence of the Local Mucosal Microenvironment

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2010
Charu Kaushic
Citation Kaushic C, Ferreira VH, Kafka JK, Nazli A. HIV infection in the female genital tract: discrete influence of the local mucosal microenvironment. Am J Reprod Immunol 2010 Women acquire HIV infections predominantly at the genital mucosa through heterosexual transmission. Therefore, the immune milieu at female genital surfaces is a critical determinant of HIV susceptibility. In this review, we recapitulate the evidence suggesting that several distinctive innate immune mechanisms in the female genital tract (FGT) serve to significantly deter or facilitate HIV-1 infection. Epithelial cells lining the FGT play a key role in forming a primary barrier to HIV entry. These cells express Toll-like receptors and other receptors that recognize and respond directly to pathogens, including HIV-1. In addition, innate biological factors produced by epithelial and other cells in the FGT have anti-HIV activity. Female sex hormones, co-infection with other pathogens and components in semen may also exacerbate or down-modulate HIV transmission. A combination of innate and adaptive immune factors and their interactions with the local microenvironment determine the outcome of HIV transmission. Improving our understanding of the female genital microenvironment will be useful in developing treatments that augment and sustain protective immune responses in the genital mucosa, such as microbicides and vaccines, and will provide greater insight into viral pathogenesis in the FGT. [source]

Antigen Presentation by Human Uterine Epithelial Cells to Autologous T Cells

AMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 1 2006
John V. Fahey
Problem, Epithelial cells, as sentinels of immune protection in the endometrium, use innate immune mechanisms to protect against infection from pathogenic microbes. Our goal in this study was to assess the ability of human uterine epithelial cells to present antigen to cells of the adaptive immune system. Method of study, Highly purified preparations of uterine epithelial cells from 11 patients were assessed for their ability to present tetanus toxoid (TT) to autologous T cells. Leukocyte contamination in the epithelial cell preparations was numerically and functionally determined. Using confocal microscopy, epithelial cells were tested for the expression of CD40 and CD1d. Results, Purified preparations of endometrial epithelial cells isolated from every patient presented TT recall antigen to autologous T cells. Leukocyte contamination of epithelial cell preparations was insignificant. Uterine epithelial cells express CD40 and CD1d. Conclusion, Antigen presentation is an additional aspect of uterine epithelial cell function in maintaining women's health. [source]