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Full-Text Articles in Medicine and Health Sciences
Immune Cd8+ T Cells Prevent Reactivation Of Toxoplasma Gondii Infection In The Immunocompromised Host, Imtiaz A. Khan, William R. Green, Lloyd H. Kasper, Kathy A. Green, Joseph D. Schwartzman
Immune Cd8+ T Cells Prevent Reactivation Of Toxoplasma Gondii Infection In The Immunocompromised Host, Imtiaz A. Khan, William R. Green, Lloyd H. Kasper, Kathy A. Green, Joseph D. Schwartzman
Dartmouth Scholarship
Toxoplasma gondii remains a serious cause of morbidity and mortality in individuals that are immunosuppressed, patients with AIDS in particular. The cellular immune response, especially by gamma interferon (IFN-γ)-producing CD8+ T cells, is an essential component of protective immunity against the parasite. In the present study the role of CD8+ T cells during the reactivation of Toxoplasma infection in an immunocompromised murine model was evaluated. Chronically infected mice were challenged with LP-BM5 virus, and the kinetics of CD8+ T-cell function was studied. At 10 weeks after viral infection, mice showed obvious signs of systemic illness and began …
Immune Responses Induced By Gene Gun Or Intramuscular Injection Of Dna Vaccines That Express Immunogenic Regions Of The Serine Repeat Antigen From Plasmodium Falciparum, Alexia A. Belperron, David Feltquate, Barbara A. Fox, Toshihiro Horii, David J. Bzik
Immune Responses Induced By Gene Gun Or Intramuscular Injection Of Dna Vaccines That Express Immunogenic Regions Of The Serine Repeat Antigen From Plasmodium Falciparum, Alexia A. Belperron, David Feltquate, Barbara A. Fox, Toshihiro Horii, David J. Bzik
Dartmouth Scholarship
The liver- and blood-stage-expressed serine repeat antigen (SERA) of Plasmodium falciparum is a candidate protein for a human malaria vaccine. We compared the immune responses induced in mice immunized with SERA-expressing plasmid DNA vaccines delivered by intramuscular (i.m.) injection or delivered intradermally by Gene Gun immunization. Mice were immunized with a pcdna3 plasmid encoding the entire 47-kDa domain of SERA (amino acids 17 to 382) or the N-terminal domain (amino acids 17 to 110) of SERA. Minimal antibody responses were detected following DNA vaccination with the N-terminal domain of SERA, suggesting that the N-terminal domain alone is not highly immunogenic …
Differential Transcription Of The Tcpph Operon Confers Biotype-Specific Control Of The Vibrio Cholerae Toxr Virulence Regulon, Yvette M. Murley, Patricia A. Carroll, Karen Skorupski, Ronald K. Taylor, Stephen B. Calderwood
Differential Transcription Of The Tcpph Operon Confers Biotype-Specific Control Of The Vibrio Cholerae Toxr Virulence Regulon, Yvette M. Murley, Patricia A. Carroll, Karen Skorupski, Ronald K. Taylor, Stephen B. Calderwood
Dartmouth Scholarship
Epidemic strains of Vibrio cholerae O1 are divided into two biotypes, classical and El Tor. In both biotypes, regulation of virulence gene expression depends on a cascade in which ToxR activates expression of ToxT, and ToxT activates expression of cholera toxin and other virulence genes. In the classical biotype, maximal expression of this ToxR regulon in vitro occurs at 30 degrees C at pH 6.5 (ToxR-inducing conditions), whereas in the El Tor biotype, production of these virulence genes only occurs under very limited conditions and not in response to temperature and pH; this difference between biotypes is mediated at the …
Interruption Of Multiple Cellular Processes In Ht-29 Epithelial Cells By Pseudomonas Aeruginosa Exoenzyme S, Joan C. Olson, Jennifer E. Fraylick, Eileen M. Mcguffie, Katherine M. Dolan, Timothy L. Yahr, Dara W. Frank, Timothy S. Vincent
Interruption Of Multiple Cellular Processes In Ht-29 Epithelial Cells By Pseudomonas Aeruginosa Exoenzyme S, Joan C. Olson, Jennifer E. Fraylick, Eileen M. Mcguffie, Katherine M. Dolan, Timothy L. Yahr, Dara W. Frank, Timothy S. Vincent
Dartmouth Scholarship
Exoenzyme S (ExoS), an ADP-ribosylating enzyme produced by the opportunistic pathogen Pseudomonas aeruginosa, is directly translocated into eukaryotic cells by bacterial contact. Within the cell, ExoS ADP-ribosylates the cell signaling protein Ras and causes inhibition of DNA synthesis and alterations in cytoskeletal structure. To further understand the interrelationship of the different cellular effects of ExoS, functional analyses were performed on HT-29 epithelial cells after exposure to ExoS-producing P. aeruginosa 388 and the non-ExoS-producing strain 388DeltaS. Two different mechanisms of morphological alteration were identified: (i) a more-transient and less-severe cell rounding caused by the non-ExoS-producing strain 388DeltaS and (ii) a more-severe, …
Attachment Ligands Of Viable Toxoplasma Gondii Induce Soluble Immunosuppressive Factors In Human Monocytes, Jacqueline Y. Channon, Edward I. Suh, Rosanne M. Seguin, Lloyd H. Kasper
Attachment Ligands Of Viable Toxoplasma Gondii Induce Soluble Immunosuppressive Factors In Human Monocytes, Jacqueline Y. Channon, Edward I. Suh, Rosanne M. Seguin, Lloyd H. Kasper
Dartmouth Scholarship
Previous studies have demonstrated that surface antigen proteins, in particular SAG-1, of Toxoplasma gondii are important to this parasite as attachment ligands for the host cell. An in vitro assay was developed to test whether these ligands and other secretory proteins are involved in the immune response of human cells to toxoplasma. Human monocytes were infected with tachyzoites in the presence of antiparasite antibodies, and their effect on mitogen-induced lymphoproliferation was examined. The presence of antibody to either parasite-excreted proteins (MIC-1 and MIC-2) or surface proteins (SAG-1 and SAG-2) during infection neutralized the marked decrease seen in mitogen-induced lymphoproliferation in …
Role Of Gamma Interferon In Cellular Immune Response Against Murine Encephalitozoon Cuniculi Infection, Imtiaz A. Khan, Magali Moretto
Role Of Gamma Interferon In Cellular Immune Response Against Murine Encephalitozoon Cuniculi Infection, Imtiaz A. Khan, Magali Moretto
Dartmouth Scholarship
Microsporidia are obligate intracellular protozoan parasites that cause a wide variety of opportunistic infection in patients with AIDS. Because it is able to grow in vitro, Encephalitozoon cuniculi is currently the best-studied microsporidian. T cells mediate protective immunity against this parasite. Splenocytes obtained from infected mice proliferate in vitro in response to irradiated parasites. A transient state of hyporesponsiveness to parasite antigen and mitogen was observed at day 17 postinfection. This downregulatory response could be partially reversed by addition of nitric oxide (NO) antagonist to the culture. Mice infected withE. cuniculi secrete significant levels of gamma interferon (IFN-γ). Treatment …
Fas-Fasl Interaction Involved In Pathogenesis Of Ocular Toxoplasmosis In Mice, Mark S. Hu, Joseph D. Schwartzman, Grant R. Yeaman, Jane Collins, Rosanne Seguin, Imtiaz A. Khan, Lloyd H. Kasper
Fas-Fasl Interaction Involved In Pathogenesis Of Ocular Toxoplasmosis In Mice, Mark S. Hu, Joseph D. Schwartzman, Grant R. Yeaman, Jane Collins, Rosanne Seguin, Imtiaz A. Khan, Lloyd H. Kasper
Dartmouth Scholarship
Ocular toxoplasmosis is a potentially blinding intraocular inflammation. The intent of this study was to investigate the role of Fas-FasL interaction in a murine model of acquired ocular toxoplasmosis induced by intracameral inoculation of Toxoplasma gondii. Intraocular inflammation, Fas and FasL expression on lymphocytes and on ocular tissues, the occurrence of apoptosis, and the frequency of CD8+ and CD4+ T cells in the infected eyes were analyzed in C57BL/6 (B6) mice. Susceptibility to parasite-induced intraocular inflammation was observed in Fas-deficient (B6-lpr) and FasL-deficient (B6-gld) mice. Inoculation of 5,000 T. gondii tachyzoites induced significant …