Lesional T cells and dermal dendrocytes in psoriasis plaque express increased levels of granulysin
ABSTRACT Granulysin is a broad-spectrum potent antimicrobial peptide produced by the immunocytes. We determined granulysin levels in certain cutaneous inflammatory diseases and correlated expression of granulysin with the relative risks of secondary infections in these conditions. In immunohistochemistry stains a monoclonal antigranulysin antibody was used at 1:150 dilutions. Compared with atopic dermatitis and nummular eczema lesions where secondary infection with Staphylococcus aureus is very common, we found that a significantly increased number of granulysin-positive T cells (P < .01) were present in psoriatic plaques. Psoriasis plaques are heavily colonized with S aureus . It is a well-known observation that despite open cracks and fissures these plaques do not get infected. Increased levels of granulysin provide an explanation for relative immunity of psoriatic plaques against both gram-positive and gram-negative bacterial infections.
Conference Paper: The effects of packet reordering in a wireless multimedia environment[Show abstract] [Hide abstract]
ABSTRACT: Packet reordering has been shown to be an ever-increasing phenomenon on the Internet and must be taken into account when considering performance analysis of both fixed, wireless and mixed media networks. Previous work (J. Bennet et al., 1999) has demonstrated that TCP suffers degraded performance in situations of high packet reordering. This paper will consider why video traffic over UDP also performs badly in situations of high packet reordering, due to the temporal inter-packet dependencies introduced by the MPEG video encoding structure. Wireless networks are especially prone to problems due to the higher levels of link layer retransmissions found in noisy wireless environments. An experimental investigation into the effects of video packet reordering using the Windows Media streaming system is presented. A method for invoking packet reordering is introduced, and a tool for client-side measurements of video quality is presented. Typical measurements of video performance undergoing reordering are shown, with a study of buffering occupancy at the client, and the potential impact this could have on video packet reordering demonstrated.Wireless Communication Systems, 2004, 1st International Symposium on; 10/2004
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ABSTRACT: The recent global increase in cases of tuberculosis and the emergence of multidrug-resistant strains of tuberculosis have focused attention on the molecular mechanisms of human antimycobacterial immunity. The macrophage is not only the primary site for Mycobacterium tuberculosis growth but also ordinarily provides the primary lines of host defense against invading pathogens in its role as an effector of innate immunity. The ability of M. tuberculosis to survive and replicate in the host macrophage is critical to its pathogenesis, emphasizing a need for a clearer understanding of its interactions with the host macrophage. Macrophages use varied strategies to kill and destroy invading organisms, including production of reactive nitrogen and oxygen intermediates, phagosome maturation and acidification, fusion with lysosomes, exposure to defensins and host cell apoptosis. In human, granulysin is a recently identified antimicrobial protein expressed on cytotoxic T cells, natural killer (NK) cells and NKT cells. It has been shown that granulysin contributes to the defense mechanisms against mycobacterial infection. We hypothesized that human macrophages may possess antimicrobial substances, such as granulysin, and play a role in the defense mechanism.Pathologie Biologie 10/2005; 53(8):516-521. DOI:10.1016/j.patbio.2005.07.003 · 1.07 Impact Factor
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ABSTRACT: The ability of CD8+ T cells to kill intracellular pathogens depends upon their capacity to attract infected cells as well as their secretion of cytolytic and antimicrobial effector molecules. We examined the Ag-induced expression of three immune effector molecules contained within cytoplasmic granules of human CD8+ T cells: the chemokine CCL5, the cytolytic molecule perforin, and the antimicrobial protein granulysin. Macrophages infected with virulent Mycobacterium tuberculosis triggered the expression of CCL5 in CD8+ T cells only in donors with previous exposure to the tuberculosis bacteria, not in naive donors. Functionally, CCL5 efficiently attracted M. tuberculosis-infected macrophages, but failed to exert direct antibacterial activity. Infected macrophages also triggered the expression of granulysin in CD8+ T cells, and granulysin was found to be highly active against drug-susceptible and drug-resistant M. tuberculosis clinical isolates. The vast majority of CCL5-positive cells coexpressed granulysin and perforin. Taken together, this report provides evidence that a subset of CD8+ T cells coordinately expresses CCL5, perforin and granulysin, thereby providing a host mechanism to attract M. tuberculosis-infected macrophages and kill the intracellular pathogen.The Journal of Immunology 01/2006; 175(11):7474-83. DOI:10.4049/jimmunol.175.11.7474 · 5.36 Impact Factor