Medical Immunology Commons^™

Inhibition Of Histone Methyltransferase Ezh2 For Immune Interception Of Colorectal Cancer In Lynch Syndrome, Charles M Bowen, Fahriye Duzagac, Abel Martel-Martel, Laura Reyes-Uribe, Mahira Zaheer, Jacklyn Thompson, Nan Deng, Ria Sinha, Soham Mazumdar, Melissa W Taggart, Abhinav K Jain, Elena Tosti, Winfried Edelmann, Krishna M Sinha, Eduardo Vilar

Faculty, Staff and Student Publications

Colorectal precancers in Lynch syndrome (LS) exhibit a distinct immune profile, presenting unique opportunities for developing immune-interception strategies to prevent carcinogenesis. Epigenetic modulation by EZH2 of immune-related genes is implicated in the carcinogenesis of different cancer types, including colorectal cancer. This study utilizes a mouse model of LS and ex vivo colonic organoids to assess the effects of the EZH2 inhibitor GSK503 on immune regulatory pathways, tumorigenesis, and epigenetic reprogramming. Our findings revealed that GSK503 significantly increased CD4+ and CD8+ T cells in both splenocytes and colonic mucosa of treated mice compared with controls. Additionally, a preventive dose of GSK503 …

Stat3 Inhibition In Combination With Cd47 Blockade Inhibits Osteosarcoma Lung Metastasis, Pradeep Shrestha, Rejeena Shrestha, You Zhou, Rafal Zielinski, Waldemar Priebe, Eugenie S Kleinerman

Faculty, Staff and Student Publications

Background: New therapies are urgently needed for patients with osteosarcoma (OS). STAT3 and CD47 are potential therapeutic target in OS. Here we investigated the therapeutic activity of the orally bioavailable STAT3 inhibitor, WP1066, and anti-CD47 antibody using OS mouse models.

Methods: Cytotoxic effect of WP1066 against OS cell lines and its immunomodulatory effects were evaluated in vitro. Experimental metastasis and orthotopic syngeneic mouse models were used to investigate the therapeutic efficacy of WP1066 and anti-CD47 antibody. Further flow cytometric analysis was performed.

Results: STAT3 was constitutively activated in multiple human and mouse OS cell lines. WP1066 suppressed STAT3 activation …

Administration Of Anti-Gfap Antibodies Increases Cgrp Expression And Increases Pain Hypersensitivity In Spinal Cord Injured Animals, Georgene W Hergenroeder, Samuel T Molina, Juan J Herrera

Faculty, Staff and Student Publications

Background: Spinal cord injury (SCI) results in a multitude of cellular and pathological changes including neuronal loss, axonal damage, gliosis, and loss of motor and sensory function. In 40%-70% of patients, SCI can also trigger the development of neuropathic pain. Our previous study demonstrated that SCI patients who developed autoantibodies to glial fibrillary acidic protein (GFAP) were at increased risk for the subsequent development of neuropathic pain. However, whether GFAP autoantibodies (GFAPab) contribute to the development of neuropathic pain after SCI had yet to be examined.

Objective: Using a mid-thoracic contusion model of SCI in male Sprague-Dawley rats, we examined …

Immune Responses Drive Chorioretinitis And Retinal Pathology After Neonatal Cmv Infection, Jessica L. Mccord, John Y.S. Han, Ross E. Staudt, Nancy J. Philp Phd, Christopher M. Snyder

Department of Microbiology and Immunology Faculty Papers

Human cytomegalovirus (CMV) causes a common congenital infection leading to long-term neurological impairments including brain, cochlear, and ocular pathology. Infection of newborn mice with murine (M)CMV is an established model of neuropathology caused by congenital CMV infection, with recent work suggesting that brain pathology may be driven by immune responses. In the eye, however, CMV retinitis is thought to result from virus-driven necrosis in the absence of T cell responses. We found that MCMV infection of newborn mice recapitulates human eye disease after congenital CMV infection, including focal chorioretinitis, inflamed vasculature, and disrupted blood-retinal barriers. Moreover, infection drove extensive T …

Advances In Immunocompetent Mouse And Rat Models, Wen Bu, Yi Li

Center on Aging Staff Publications

Rodent models of breast cancer have played critical roles in our understanding of breast cancer development and progression as well as preclinical testing of cancer prevention and therapeutics. In this article, we first review the values and challenges of conventional genetically engineered mouse (GEM) models and newer iterations of these models, especially those with inducible or conditional regulation of oncogenes and tumor suppressors. Then, we discuss nongermline (somatic) GEM models of breast cancer with temporospatial control, made possible by intraductal injection of viral vectors to deliver oncogenes or to manipulate the genome of mammary epithelial cells. Next, we introduce the …

Intranasal Sensitization Model Of Alopecia Areata Using Pertussis Toxin As Adjuvant, Yuying Liu, Jasmin Freeborn, Beanna Okeugo, Shabba A Armbrister, Zeina M Saleh, Ana Beatriz Fadhel Alvarez, Thomas K Hoang, Evelyn S Park, John William Lindsey, Ronald P Rapini, Steven Glazer, Keith Rubin, Jon Marc Rhoads

Faculty, Staff and Student Publications

Background: Nasopharyngeal Bordetella pertussis (BP) colonization is common, with about 5% of individuals having PCR evidence of subclinical BP infection on nasal swab, even in countries with high vaccination rates. BP secretes pertussis toxin (PTx). PTx is an adjuvant commonly used to induce autoimmunity in multiple animal models of human disease. Colocalization of PTx and myelin from myelinated nerves in the nasopharynx may lead to host sensitization to myelin with subsequent autoimmune pathology.

Methods: C57BL/6J female adult mice were given varied doses and schedules of intranasal PTx, MOG35-55 antigen, or controls to test whether intranasal administration of PTx and myelin …

Targeting Pd-L2-Rgmb Overcomes Microbiome-Related Immunotherapy Resistance, Joon Seok Park, Francesca S Gazzaniga, Meng Wu, Amalia K Luthens, Jacob Gillis, Wen Zheng, Martin W Lafleur, Sarah B Johnson, Golnaz Morad, Elizabeth M Park, Yifan Zhou, Stephanie S Watowich, Jennifer A Wargo, Gordon J Freeman, Dennis L Kasper, Arlene H Sharpe

Faculty, Staff and Student Publications

The gut microbiota is a crucial regulator of anti-tumour immunity during immune checkpoint inhibitor therapy. Several bacteria that promote an anti-tumour response to immune checkpoint inhibitors have been identified in mice1-6. Moreover, transplantation of faecal specimens from responders can improve the efficacy of anti-PD-1 therapy in patients with melanoma7,8. However, the increased efficacy from faecal transplants is variable and how gut bacteria promote anti-tumour immunity remains unclear. Here we show that the gut microbiome downregulates PD-L2 expression and its binding partner repulsive guidance molecule b (RGMb) to promote anti-tumour immunity and identify bacterial species that mediate this effect. PD-L1 and …

The Lack Of Natural Igm Increases Susceptibility And Impairs Anti-Vi Polysaccharide Igg Responses In A Mouse Model Of Typhoid, Akhil S. Alugupalli, Matthew P. Cravens, Justin A. Walker, Dania Gulandijany, Gregory S. Dickinson, Genevieve Lewis, Gudrun F. Debes, Dieter M. Schifferli, Andreas J. Bäumler, Kishore R. Alugupalli

Department of Microbiology and Immunology Faculty Papers

Circulating IgM present in the body prior to any apparent Ag exposure is referred to as natural IgM. Natural IgM provides protective immunity against a variety of pathogens. Salmonella enterica serovar Typhi (S. Typhi) is the causative agent of typhoid fever in humans. Because mice are not permissive to S. Typhi infection, we employed a murine model of typhoid using S. enterica serovar Typhimurium expressing the Vi polysaccharide (ViPS) of S. Typhi (S. Typhimurium strain RC60) to evaluate the role of natural IgM in pathogenesis. We found that natural mouse IgM binds to S. Typhi and S. Typhimurium. The severity …

Systemic Ablation Of Camkk2 Impairs Metastatic Colonization And Improves Insulin Sensitivity In Tramp Mice: Evidence For Cancer Cell-Extrinsic Camkk2 Functions In Prostate Cancer, Thomas L Pulliam, Dominik Awad, Jenny J Han, Mollianne M Murray, Jeffrey J Ackroyd, Pavithr Goli, Jonathan S Oakhill, John W Scott, Michael M Ittmann, Daniel E Frigo

Faculty, Staff and Students Publications

Despite early studies linking calcium-calmodulin protein kinase kinase 2 (CAMKK2) to prostate cancer cell migration and invasion, the role of CAMKK2 in metastasis in vivo remains unclear. Moreover, while CAMKK2 is known to regulate systemic metabolism, whether CAMKK2's effects on whole-body metabolism would impact prostate cancer progression and/or related comorbidities is not known. Here, we demonstrate that germline ablation of

Targeting Etosis By Mir-155 Inhibition Mitigates Mixed Granulocytic Asthmatic Lung Inflammation, Ji Young Kim, Patrick Stevens, Manjula Karpurapu, Hyunwook Lee, Joshua A Englert, Pearlly Yan, Tae Jin Lee, Navjot Pabla, Maciej Pietrzak, Gye Young Park, John W Christman, Sangwoon Chung

Faculty, Staff and Student Publications

Asthma is phenotypically heterogeneous with several distinctive pathological mechanistic pathways. Previous studies indicate that neutrophilic asthma has a poor response to standard asthma treatments comprising inhaled corticosteroids. Therefore, it is important to identify critical factors that contribute to increased numbers of neutrophils in asthma patients whose symptoms are poorly controlled by conventional therapy. Leukocytes release chromatin fibers, referred to as extracellular traps (ETs) consisting of double-stranded (ds) DNA, histones, and granule contents. Excessive components of ETs contribute to the pathophysiology of asthma; however, it is unclear how ETs drive asthma phenotypes and whether they could be a potential therapeutic target. …

Interleukin-10 Suppression Enhances T-Cell Antitumor Immunity And Responses To Checkpoint Blockade In Chronic Lymphocytic Leukemia., J R Rivas, Y Liu, S S Alhakeem, J M Eckenrode, F Marti, J P Collard, Y Zhang, K A Shaaban, N Muthusamy, G C Hildebrandt, L Chen, J S Thorson, M Leggas, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

T-cell dysfunction is a hallmark of B-cell Chronic Lymphocytic Leukemia (CLL), where CLL cells downregulate T-cell responses through regulatory molecules including programmed death ligand-1 (PD-L1) and Interleukin-10 (IL-10). Immune checkpoint blockade (ICB) aims to restore T-cell function by preventing the ligation of inhibitory receptors like PD-1. However, most CLL patients do not respond well to this therapy. Thus, we investigated whether IL-10 suppression could enhance antitumor T-cell activity and responses to ICB. Since CLL IL-10 expression depends on Sp1, we utilized a novel, better tolerated analogue of the Sp1 inhibitor mithramycin (MTM

Mtor-Initiated Metabolic Switch And Degeneration In The Retinal Pigment Epithelium, Young-Mi Go, Jing Zhang, Jolyn Fernandes, Christopher Litwin, Rui Chen, Theodore G Wensel, Dean P Jones, Jiyang Cai, Yan Chen

Faculty, Staff and Students Publications

The retinal pigment epithelium (RPE) is a particularly vulnerable tissue to age-dependent degeneration. Over the life span, the RPE develops an expanded endo-lysosomal compartment to maintain the high efficiency of phagocytosis and degradation of photoreceptor outer segments (POS) necessary for photoreceptor survival. As the assembly and activation of the mechanistic target of rapamycin complex 1 (mTORC1) occur on the lysosome surface, increased lysosome mass with aging leads to higher mTORC1 activity. The functional consequences of hyperactive mTORC1 in the RPE are unclear. In the current study, we used integrated high-resolution metabolomic and genomic approaches to examine mice with RPE-specific deletion …

Chronic Lymphocytic Leukemia-Derived Il-10 Suppresses Antitumor Immunity., Sara S Alhakeem, Mary K Mckenna, Karine Z Oben, Sunil K Noothi, Jacqueline R Rivas, Gerhard C Hildebrandt, Roger A Fleischman, Vivek M Rangnekar, Natarajan Muthusamy, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Chronic lymphocytic leukemia (CLL) patients progressively develop an immunosuppressive state. CLL patients have more plasma IL-10, an anti-inflammatory cytokine, than healthy controls. In vitro human CLL cells produce IL-10 in response to BCR cross-linking. We used the transgenic Eμ-T cell leukemia oncogene-1 (

Herpes Simplex Virus And Interferon Signaling Induce Novel Autophagic Clusters In Sensory Neurons, Sarah Katzenell, David A. Leib

Dartmouth Scholarship

Herpes simplex virus 1 (HSV-1) establishes lifelong infection in the neurons of trigeminal ganglia (TG), cycling between productive infection and latency. Neuronal antiviral responses are driven by type I interferon (IFN) and are crucial to controlling HSV-1 virulence. Autophagy also plays a role in this neuronal antiviral response, but the mechanism remains obscure. In this study, HSV-1 infection of murine TG neurons triggered unusual clusters of autophagosomes, predominantly in neurons lacking detectable HSV-1 antigen. Treatment of neurons with IFN-β induced a similar response, and cluster formation by infection or IFN treatment was dependent upon an intact IFN-signaling pathway. The autophagic …

Borrelia Burgdorferi Reva Significantly Affects Pathogenicity And Host Response In The Mouse Model Of Lyme Disease, Rebecca Byram, Robert A. Gaultney, Angela M. Floden, Christopher Hellekson, Brandee L. Stone, Amy Bowman, Brian Stevenson, Barbara J. B. Johnson, Catherine A. Brissette

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Lyme disease spirochete, Borrelia burgdorferi, expresses RevA and numerous outer surface lipoproteins during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA is poised to interact with the extracellular matrix of the host. To further define the role(s) of RevA during mammalian infection, we created a mutant that is unable to produce RevA. The mutant was still infectious to mice, although it was significantly less well able to infect cardiac tissues. Complementation of the mutant with a wild-type revA gene restored heart infectivity to wild-type levels. Additionally, revA mutants led to increased evidence of arthritis, …

Early Inflammatory Mediator Gene Expression In Two Models Of Traumatic Brain Injury: Ex Vivo Cortical Slice In Mice And In Vivo Cortical Impact In Piglets, David J. Graber, Beth A. Costine, William F. Hickey

Dartmouth Scholarship

Background: The immunological response during the first 24 hours after traumatic brain injury (TBI) may be a critical therapeutic interval for limiting the secondary neuronal damage that is influenced by enhanced inflammatory mediator expression.

Methods: To gain further insight of the early injury response, we examined the expression of several inflammatory genes by real-time qPCR as a function of time or distance from injury in two distinct mammalian models: an ex vivo mouse cortical slice injury system and an in vivo piglet model of brain injury.

Apparent Role For Borrelia Burgdorferi Luxs During Mammalian Infection, William K. Arnold, Christina R. Savage, Alyssa D. Antonicello, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Lyme disease spirochete, Borrelia burgdorferi, controls protein expression patterns during its tick-mammal infection cycle. Earlier studies demonstrated that B. burgdorferi synthesizes 4,5-dihydroxy-2,3-pentanedione (autoinducer-2 [AI-2]) and responds to AI-2 by measurably changing production of several infection-associated proteins. luxS mutants, which are unable to produce AI-2, exhibit altered production of several proteins. B. burgdorferi cannot utilize the other product of LuxS, homocysteine, indicating that phenotypes of luxS mutants are not due to the absence of that molecule. Although a previous study found that a luxS mutant was capable of infecting mice, a critical caveat to those results is that bacterial …

Mcl1 Enhances The Survival Of Cd8+ Memory T Cells After Viral Infection, Jingang Gui, Zhuting Hu, Ching-Yi Tsai, Tian Ma, Yan Song, Amanda Morales, Li-Hao Huang, Ethan Dmitrovsky, Ruth Craig, Edward Usherwood

Dartmouth Scholarship

Viral infection results in the generation of massive numbers of activated effector CD8+ T cells that recognize viral components. Most of these are short-lived effector T cells (SLECs) that die after clearance of the virus. However, a small proportion of this population survives and forms antigen-specific memory precursor effector cells (MPECs), which ultimately develop into memory cells. These can participate in a recall response upon reexposure to antigen even at protracted times postinfection. Here, antiapoptotic myeloid cell leukemia 1 (MCL1) was found to prolong survival upon T cell stimulation, and mice expressing human MCL1 as a transgene exhibited a skewing …

Site-Specific Mutation Of The Sensor Kinase Gras In Staphylococcus Aureus Alters The Adaptive Response To Distinct Cationic Antimicrobial Peptides, Ambrose L. Cheung, Arnold S. Bayer, Michael R. Yeaman, Yan Q. Xiong, Alan J. Waring, Guido Memmi, Niles Donegan

Dartmouth Scholarship

The Staphylococcus aureus two-component regulatory system, GraRS, is involved in resistance to killing by distinct host defense cationic antimicrobial peptides (HD-CAPs). It is believed to regulate downstream target genes such as mprF and dltABCD to modify the S. aureus surface charge. However, the detailed mechanism(s) by which the histidine kinase, GraS, senses specific HD-CAPs is not well defined. Here, we studied a well-characterized clinical methicillin-resistant S. aureus (MRSA) strain (MW2), its isogenic graS deletion mutant (ΔgraS strain), a nonameric extracellular loop mutant (ΔEL strain), and four residue-specific ΔEL mutants (D37A, P39A, P39S, and D35G D37G D41G strains). The ΔgraS and …

Caspase-3 Mediates The Pathogenic Effect Of Yersinia Pestis Yopm In Liver Of C57bl/6 Mice And Contributes To Yopm's Function In Spleen, Zhan Ye, Amanda A. Gorman, Annette M. Uittenbogaard, Tanya Myers-Morales, Alan M. Kaplan, Donald A. Cohen, Susan C. Straley

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The virulence protein YopM of the plague bacterium Yersinia pestis has different dominant effects in liver and spleen. Previous studies focused on spleen, where YopM inhibits accumulation of inflammatory dendritic cells. In the present study we focused on liver, where PMN function may be directly undermined by YopM without changes in inflammatory cell numbers in the initial days of infection, and foci of inflammation are easily identified. Mice were infected with parent and ΔyopM-1 Y. pestis KIM5, and effects of YopM were assessed by immunohistochemistry and determinations of bacterial viable numbers in organs. The bacteria were found …

Impact Of Distinct Poxvirus Infections On The Specificities And Functionalities Of Cd4+ T Cell Responses., Nicholas A Siciliano, Adam R Hersperger, Aimee M Lacuanan, Ren-Huan Xu, John Sidney, Alessandro Sette, Luis J Sigal, Laurence C. Eisenlohr

Department of Microbiology and Immunology Faculty Papers

UNLABELLED: The factors that determine CD4+ T cell (TCD4+) specificities, functional capacity, and memory persistence in response to complex pathogens remain unclear. We explored these parameters in the C57BL/6 mouse through comparison of two highly related (>92% homology) poxviruses: ectromelia virus (ECTV), a natural mouse pathogen, and vaccinia virus (VACV), a heterologous virus that nevertheless elicits potent immune responses. In addition to elucidating several previously unidentified major histocompatibility complex class II (MHC-II)-restricted epitopes, we observed many qualitative and quantitative differences between the TCD4+ repertoires, including responses not elicited by VACV despite complete sequence conservation. In addition, we observed functional …

Cyclic Di-Gmp-Dependent Signaling Pathways In The Pathogenic Firmicute Listeria Monocytogenes, Li-Hong Chen, Volkan K. Köseoğlu, Zehra T. Güvener, Tanya Myers-Morales, Joseph M. Reed, Sarah E. F. D'Orazio, Kurt W. Miller, Mark Gomelsky

Microbiology, Immunology, and Molecular Genetics Faculty Publications

We characterized key components and major targets of the c-di-GMP signaling pathways in the foodborne pathogen Listeria monocytogenes, identified a new c-di-GMP-inducible exopolysaccharide responsible for motility inhibition, cell aggregation, and enhanced tolerance to disinfectants and desiccation, and provided first insights into the role of c-di-GMP signaling in listerial virulence. Genome-wide genetic and biochemical analyses of c-di-GMP signaling pathways revealed that L. monocytogenes has three GGDEF domain proteins, DgcA (Lmo1911), DgcB (Lmo1912) and DgcC (Lmo2174), that possess diguanylate cyclase activity, and three EAL domain proteins, PdeB (Lmo0131), PdeC (Lmo1914) and PdeD (Lmo0111), that possess c-di-GMP phosphodiesterase activity. Deletion of all …

Vcam-1/Α4Β1 Integrin Interaction Is Crucial For Prompt Recruitment Of Immune T Cells Into The Brain During The Early Stage Of Reactivation Of Chronic Infection With Toxoplasma Gondii To Prevent Toxoplasmic Encephalitis, Qila Sa, Eri Ochiai, Tomoko Sengoku, Melinda E. Wilson, Morgan Brogli, Stephen Crutcher, Sara A. Michie, Baohui Xu, Laura Payne, Xisheng Wang, Yasuhiro Suzuki

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Reactivation of chronic infection with Toxoplasma gondii can cause life-threatening toxoplasmic encephalitis in immunocompromised individuals. We examined the role of VCAM-1/α4β1 integrin interaction in T cell recruitment to prevent reactivation of the infection in the brain. SCID mice were infected and treated with sulfadiazine to establish a chronic infection. VCAM-1 and ICAM-1 were the endothelial adhesion molecules detected on cerebral vessels of the infected SCID and wild-type animals. Immune T cells from infected wild-type mice were treated with anti-α4 integrin or control antibodies and transferred into infected SCID or nude mice, and the animals received the same antibody every other …

Efficient B Cell Responses To Borrelia Hermsii Infection Depend On Baff And Baffr But Not Taci., Gregory S. Dickinson, Phd, Guizhi Sun, Richard J Bram, Kishore Alugupalli

Department of Microbiology and Immunology Faculty Papers

T cell-independent antibody responses develop rapidly, within 3 to 4 days, and are critical for preventing blood-borne pathogens from evolving into life-threatening infections. The interaction of BAFF, also known as BLyS, with its receptors BAFFR and TACI on B cells is critical for B cell homeostasis and function. Using a synthetic polysaccharide antigen, it has previously been shown that TACI is critical for T cell-independent antibody responses. To examine the role of BAFFR and TACI in T cell-independent antibody responses to an active infection, we utilized the Borrelia hermsii infection system. In this infection system, T cell-independent responses mediated by …

Use Of Irf-3 And/Or Irf-7 Knockout Mice To Study Viral Pathogenesis: Lessons From A Murine Retrovirus-Induced Aids Model, Megan A. O'Connor, William R. Green

Dartmouth Scholarship

Interferon regulatory factor (IRF) regulation of the type I interferon response has not been extensively explored in murine retroviral infections. IRF-3(-/-) and select IRF-3/7(-/-) mice were resistant to LP-BM5-induced pathogenesis. However, further analyses strongly suggested that resistance could be attributed to strain 129-specific contamination of the known retrovirus resistance gene Fv1. Therefore, caution should be taken when interpreting phenotypes observed in these knockout mice, as strain 129-derived genetic polymorphisms may explain observed differences.

Innate And Adaptive Immunity To The Nematode Strongyloides Stercoralis In A Mouse Model., Sandra Bonne-Annee, Jessica A. Hess, David Abraham

Department of Microbiology and Immunology Faculty Papers

Mice have been used to the study the mechanisms of protective innate and adaptive immunity to larval Strongyloides stercoralis. During primary infection, neutrophils and eosinophils are attracted by parasite components and kill the larvae by release of granule products. Eosinophils also function as antigen-presenting cells for the induction of a Th2 response. B cells produce both IgM and IgG that collaborate with neutrophils to kill worms in the adaptive immune response. Vaccine studies have identified a recombinant diagnostic antigen that induced high levels of immunity to infection with S. stercoralis in mice. These studies demonstrate that there are redundancies in …

Lack Of Il-15 Results In The Suboptimal Priming Of Cd4+ T Cell Response Against An Intracellular Parasite, Crescent L. Combe, Magali M. Moretto, Joseph D. Schwartzman, Jason P. Gigley, David J. Bzik, Imtiaz A. Khan

Dartmouth Scholarship

IFN-gamma-producing CD4+ T cells, although important for protection against acute Toxoplasma gondii infection, can cause gut pathology, which may prove to be detrimental for host survival. Here we show that mice lacking IL-15 gene develop a down-regulated IFN-gamma-producing CD4+ T cell response against the parasite, which leads to a reduction in gut necrosis and increased level of survival against infection. Moreover, transfer of immune CD4+ T cells from WT to IL-15-/- mice reversed inhibition of gut pathology and caused mortality equivalent to levels of parental WT mice. Down-regulated CD4+ T cell response in the absence of IL-15, manifested as reduced …

Cd4+ T Cells In The Pathogenesis Of Murine Ocular Toxoplasmosis, Fangli Lu, Shiguang Huang, Lloyd H. Kasper

Dartmouth Scholarship

The role of CD4⁺ T cells in the pathogenesis of ocular toxoplasmosis was investigated in murine models utilizing inbred C57BL/6 mice deficient either in CD4⁺, CD8⁺, or B cells (μMT). Severe necrosis and inflammation with replicating parasites were observed in the eyes of control mice after primary ocular infection, and near-normal histology with few tachyzoites was observed in the eyes of mice immunized intraperitoneally with the avirulent ts-4 strain followed by intraocular challenge with the RH strain of Toxoplasma gondii. In contrast, mild inflammation without evidence of necrosis associated with increased parasite burdens were …

Immune Responses Of Different Mouse Strains After Challenge With Equivalent Lethal Doses Of Toxoplasma Gondii, Y. H. Lee, L. H. Kasper

Dartmouth Scholarship

Most immunological studies that utilize different strains of inbred mice following T. gondii infection fail to compensate for differences in host susceptibility to the size of the parasite innoculum. To address this concern, susceptible C57BL/6 and resistant CBA/J mice were orally infected with either an equivalent 50 % lethal dose (LD₅₀) of brain cysts of the 76K strain of T. gondii (15 cysts in C57BL/6, 400 cysts in CBA/J) or the same dose of parasites in each mouse strain. C57BL/6 mice receiving 400 cysts (LD₅₀ of CBA/J mice) died post infection, whereas CBA/J mice that received 15 …

Cd40-Associated Traf 6 Signaling Is Required For Disease Induction In A Retrovirus-Induced Murine Immunodeficiency, Kathy A. Green, Cory L. Ahonen, W. James Cook, William R. Green

Dartmouth Scholarship

LP-BM5 retrovirus-infected C57BL/6 mice develop splenomegaly, lymphadenopathy, hypergammaglobulinemia, and immunodeficiency; thus, this disease has been named mouse AIDS. In this syndrome, CD154/CD40 interactions are required for but do not mediate disease by upregulation of CD80 or CD86. We report here that there is nonetheless a necessity for CD40 signaling competence, specifically an intact tumor necrosis factor receptor-associated factor 6 (TRAF 6) binding site.