Medical Immunology Commons^™

Ifn-Γ Receptor And Stat1 Signaling In B Cells Are Central To Spontaneous Germinal Center Formation And Autoimmunity., Phillip P. Domeier, Sathi Babu Chodisetti, Chetna Soni, Stephanie L. Schell, Melinda J. Elias, Eric B. Wong, Timothy K. Cooper, Daisuke Kitamura, Ziaur S.M. Rahman

Department of Microbiology and Immunology Faculty Papers

Spontaneously developed germinal centers (GCs [Spt-GCs]) harbor autoreactive B cells that generate somatically mutated and class-switched pathogenic autoantibodies (auto-Abs) to promote autoimmunity. However, the mechanisms that regulate Spt-GC development are not clear. In this study, we report that B cell-intrinsic IFN-γ receptor (IFN-γR) and STAT1 signaling are required for Spt-GC and follicular T helper cell (Tfh cell) development. We further demonstrate that IFN-γR and STAT1 signaling control Spt-GC and Tfh cell formation by driving T-bet expression and IFN-γ production by B cells. Global or B cell-specific IFN-γR deficiency in autoimmune B6.Sle1b mice leads to significantly reduced Spt-GC and Tfh cell …

Vaccination Of Gerbils With Bm-103 And Bm-Ral-2 Concurrently Or As A Fusion Protein Confers Consistent And Improved Protection Against Brugia Malayi Infection., Sridhar Arumugam, Junfei Wei, Zhuyun Liu, David Abraham, Aaron Bell, Maria Elena Bottazzi, Peter J Hotez, Bin Zhan, Sara Lustigman, Thomas R Klei

Department of Microbiology and Immunology Faculty Papers

BACKGROUND: The Brugia malayi Bm-103 and Bm-RAL-2 proteins are orthologous to Onchocerca volvulus Ov-103 and Ov-RAL-2, and which were selected as the best candidates for the development of an O. volvulus vaccine. The B. malayi gerbil model was used to confirm the efficacy of these Ov vaccine candidates on adult worms and to determine whether their combination is more efficacious.

METHODOLOGY AND PRINCIPLE FINDINGS: Vaccine efficacy of recombinant Bm-103 and Bm-RAL-2 administered individually, concurrently or as a fusion protein were tested in gerbils using alum as adjuvant. Vaccination with Bm-103 resulted in worm reductions of 39%, 34% and 22% on …

Murine Cmv Infection Induces The Continuous Production Of Mucosal Resident T Cells., Corinne J Smith, Sofia Caldeira-Dantas, Holly Turula, Christopher M. Snyder

Department of Microbiology and Immunology Faculty Papers

Cytomegalovirus (CMV) is a herpesvirus that persists for life and maintains extremely large numbers of T cells with select specificities in circulation. However, it is unknown how viral persistence impacts T cell populations in mucosal sites. We found that many murine (M)CMV-specific CD8s in mucosal tissues became resident memory T cells (TRM). These cells adopted an intraepithelial localization in the salivary gland that correlated with, but did not depend on, expression of the integrin CD103. MCMV-specific TRM cells formed early after infection, and spleen-localized cells had reduced capacities to become TRM at late times. Surprisingly, however, small numbers of new …

Reverse Genetics Of Mononegavirales: How They Work, New Vaccines, And New Cancer Therapeutics., Christian K Pfaller, Roberto Cattaneo, Matthias J. Schnell

Department of Microbiology and Immunology Faculty Papers

The order Mononegavirales includes five families: Bornaviridae, Filoviridae, Nyamaviridae, Paramyxoviridae, and Rhabdoviridae. The genome of these viruses is one molecule of negative-sense single strand RNA coding for five to ten genes in a conserved order. The RNA is not infectious until packaged by the nucleocapsid protein and transcribed by the polymerase and co-factors. Reverse genetics approaches have answered fundamental questions about the biology of Mononegavirales. The lack of icosahedral symmetry and modular organization in the genome of these viruses has facilitated engineering of viruses expressing fluorescent proteins, and these fluorescent proteins have provided important insights about the molecular and cellular …

The Onchocerciasis Vaccine For Africa-Tova-Initiative., Peter J Hotez, Maria Elena Bottazzi, Bin Zhan, Benjamin L Makepeace, Thomas R Klei, David Abraham, David W Taylor, Sara Lustigman

Department of Microbiology and Immunology Faculty Papers

No abstract provided.

Memory T Cells Specific For Murine Cytomegalovirus Re-Emerge After Multiple Challenges And Recapitulate Immunity In Various Adoptive Transfer Scenarios., Michael Quinn, Holly Turula, Mayank Tandon, Berthony Deslouches, Toktam Moghbeli, Christopher M. Snyder

Department of Microbiology and Immunology Faculty Papers

Reconstitution of CMV-specific immunity after transplant remains a primary clinical objective to prevent CMV disease, and adoptive immunotherapy of CMV-specific T cells can be an effective therapeutic approach. Because of viral persistence, most CMV-specific CD8(+) T cells become terminally differentiated effector phenotype CD8(+) T cells (TEFF). A minor subset retains a memory-like phenotype (memory phenotype CD8(+) T cells [TM]), but it is unknown whether these cells retain memory function or persist over time. Interestingly, recent studies suggest that CMV-specific CD8(+) T cells with different phenotypes have different abilities to reconstitute sustained immunity after transfer. The immunology of human CMV infections …

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 …

Vaccination With A Genetically Modified Brugia Malayi Cysteine Protease Inhibitor-2 Reduces Adult Parasite Numbers And Affects The Fertility Of Female Worms Following A Subcutaneous Challenge Of Mongolian Gerbils (Meriones Unguiculatus) With B. Malayi Infective Larvae., Sridhar Arumugam, Junfei Wei, Danielle Ward, David Abraham, Sara Lustigman, Bin Zhan, Thomas R. Klei

Department of Microbiology and Immunology Faculty Papers

Vaccination of Mongolian gerbils with Brugia malayi cysteine protease inhibitor-2 in which the amino acid Asn66 was mutated to Lys66 (Bm-CPI-2M) resulted in reduced parasite numbers of 48.6% and 48.0% at 42 and 90 days p.i. with B. malayi L3s. Fertility of female worms was also affected at 90 days p.i. In vitro killing of L3s observed in the presence of gerbil peritoneal exudate cells and anti-Bm-CPI-2M sera suggests antibody-dependent cell-mediated cytotoxicity as a putative protective mechanism. These observations suggest that Bm-CPI-2M is a promising prophylactic and anti-fecundity vaccine candidate.

Epithelial Immunization Induces Polyfunctional Cd8+ T Cells And Optimal Mousepox Protection., Adam R Hersperger, Nicholas A Siciliano, Brian C Dehaven, Adam E. Snook, Laurence C. Eisenlohr

Department of Microbiology and Immunology Faculty Papers

We assessed several routes of immunization with vaccinia virus (VACV) in protecting mice against ectromelia virus (ECTV). By a wide margin, skin scarification provided the greatest protection. Humoral immunity and resident-memory T cells notwithstanding, several approaches revealed that circulating, memory CD8(+) T cells primed via scarification were functionally superior and conferred enhanced virus control. Immunization via the epithelial route warrants further investigation, as it may also provide enhanced defense against other infectious agents.

Vaccines To Combat River Blindness: Expression, Selection And Formulation Of Vaccines Against Infection With Onchocerca Volvulus In A Mouse Model., Jessica A. Hess, Bin Zhan, Sandra Bonne-Annee, Jessica M. Deckman, Maria Elena Bottazzi, Peter J. Hotez, Thomas R R. Klei, Sara Lustigman, David Abraham

Department of Microbiology and Immunology Faculty Papers

Human onchocerciasis is a neglected tropical disease caused by Onchocerca volvulus and an important cause of blindness and chronic disability in the developing world. Although mass drug administration of ivermectin has had a profound effect on control of the disease, additional tools are critically needed including the need for a vaccine against onchocerciasis. The objectives of the present study were to: (i) select antigens with known vaccine pedigrees as components of a vaccine; (ii) produce the selected vaccine antigens under controlled conditions, using two expression systems and in one laboratory and (iii) evaluate their vaccine efficacy using a single immunisation …

Systemic Hematogenous Maintenance Of Memory Inflation By Mcmv Infection., Corinne J Smith, Holly Turula, Christopher M. Snyder

Department of Microbiology and Immunology Faculty Papers

Several low-grade persistent viral infections induce and sustain very large numbers of virus-specific effector T cells. This was first described as a response to cytomegalovirus (CMV), a herpesvirus that establishes a life-long persistent/latent infection, and sustains the largest known effector T cell populations in healthy people. These T cells remain functional and traffic systemically, which has led to the recent exploration of CMV as a persistent vaccine vector. However, the maintenance of this remarkable response is not understood. Current models propose that reservoirs of viral antigen and/or latently infected cells in lymph nodes stimulate T cell proliferation and effector differentiation, …

Extracellular Traps Are Associated With Human And Mouse Neutrophil And Macrophage Mediated Killing Of Larval Strongyloides Stercoralis., Sandra Bonne-Annee, Laura A. Kerepesi, Jessica A. Hess, Jordan Wesolowski, Fabienne Paumet, James B. Lok, Thomas J. Nolan, David Abraham

Department of Microbiology and Immunology Faculty Papers

Neutrophils are multifaceted cells that are often the immune system's first line of defense. Human and murine cells release extracellular DNA traps (ETs) in response to several pathogens and diseases. Neutrophil extracellular trap (NET) formation is crucial to trapping and killing extracellular pathogens. Aside from neutrophils, macrophages and eosinophils also release ETs. We hypothesized that ETs serve as a mechanism of ensnaring the large and highly motile helminth parasite Strongyloides stercoralis thereby providing a static target for the immune response. We demonstrated that S. stercoralis larvae trigger the release of ETs by human neutrophils and macrophages. Analysis of NETs revealed …

Cd27high/Klrg1low Cd8+ T Cells That Persist Throughout Mcmv Infection Are Highly Expansive And Have The Ability To Reestablish Mcmv Immunity, Michael Quinn, Holly Turula, Christopher M. Snyder

Department of Microbiology and Immunology Faculty Papers

Abstract

Cytomegalovirus (CMV) is a herpesvirus that establishes life-long latency in 60-80% of Americans. Constant immune surveillance is necessary to prevent viral reactivation from latency and results in the accumulation of functional CMV-specific CD8+ T cells (CD8s) over time, a process termed memory inflation. As such, CMV reactivations remain a clinical concern for immunosuppressed patients and reconstituting CMV immunity is critical for the long-term prevention of CMV disease. Understanding the maintenance of memory inflation may reveal novel approaches to restore CMV immunity.

Previous work has shown that the majority of inflationary CD8s express a terminally-differentiated “effector” (T_EFF) phenotype, …

Characterization Of T-Bet And Eomes In Peripheral Human Immune Cells., James J. Knox, Gabriela L. Cosma, Michael R. Betts, Laura M. Mclane

Department of Microbiology and Immunology Faculty Papers

The T-box transcription factors T-bet and Eomesodermin (Eomes) have been well defined as key drivers of immune cell development and cytolytic function. While the majority of studies have defined the roles of these factors in the context of murine T-cells, recent results have revealed that T-bet, and possibly Eomes, are expressed in other immune cell subsets. To date, the expression patterns of these factors in subsets of human peripheral blood mononuclear cells beyond T-cells remain relatively uncharacterized. In this study, we used multiparametric flow cytometry to characterize T-bet and Eomes expression in major human blood cell subsets, including total CD4(+) …

Limited Brain Metabolism Changes Differentiate Between The Progression And Clearance Of Rabies Virus., Keith Schutsky, Carla Portocarrero, D Craig Hooper, Bernhard Dietzschold, Milosz Faber

Department of Microbiology and Immunology Faculty Papers

Central nervous system (CNS) metabolic profiles were examined from rabies virus (RABV)-infected mice that were either mock-treated or received post-exposure treatment (PET) with a single dose of the live recombinant RABV vaccine TriGAS. CNS tissue harvested from mock-treated mice at middle and late stage infection revealed numerous changes in energy metabolites, neurotransmitters and stress hormones that correlated with replication levels of viral RNA. Although the large majority of these metabolic changes were completely absent in the brains of TriGAS-treated mice most likely due to the strong reduction in virus spread, TriGAS treatment resulted in the up-regulation of the expression of …

Interleukin-7-Dependent B Lymphocytes Are Required For The Anti-Pneumococcal Polysaccharide Response And Protective Immunity To Streptococcus Pneumoniae, Gregory S. Dickinson, Phd, Raja Vuyyuru, Timothy L. Manser, Phd, John F. Kerney, Kishore Alugupalli, Phd

Department of Microbiology and Immunology Faculty Papers

Unlike human adults or adult mice, young children or young mice respond poorly to pneumococcal polysaccharides (PPS). In mice, B1b lymphocytes are the major responders to a variety of bacterial polysaccharides including PPS. Despite having B1b cells, young mice are severely impaired in responding to PPS, suggesting that B cells in the young are distinct from those in adults. Since B lymphopoeisis early in life is largely Interleukin-7 (IL-7)-independent, while in adults it is IL-7-dependent, we hypothesize that B cells developed in the presence of IL-7 are required for generating anti-PPS antibody responses. In support of this, we found that …

Myd88-Dependent Immunity To A Natural Model Of Vaccinia Virus Infection Does Not Involve Toll-Like Receptor 2., Michael L Davies, Janet J Sei, Nicholas A Siciliano, Ren-Huan Xu, Felicia Roscoe, Luis J Sigal, Laurence C. Eisenlohr, Christopher C Norbury

Department of Microbiology and Immunology Faculty Papers

UNLABELLED: Although the pattern recognition receptor Toll-like receptor 2 (TLR2) is typically thought to recognize bacterial components, it has been described to alter the induction of both innate and adaptive immunity to a number of viruses, including vaccinia virus (VACV). However, many pathogens that reportedly encode TLR2 agonists may actually be artifactually contaminated during preparation, possibly with cellular debris or merely with molecules that sensitize cells to be activated by authentic TLR2 agonists. In both humans and mice, the most relevant natural route of infection with VACV is through intradermal infection of the skin. Therefore, we examined the requirement for …

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 …

Competition For Antigen Selects T Cell Responses That Undergo Memory Inflation And Maintains Clonal Dominance During Mcmv Infection, Holly Turula, Lila A. Farrington, Corinne Smith, Ann B. Hill, Christopher M Snyder

Department of Microbiology and Immunology Faculty Papers

Cytomegalovirus (CMV) establishes a life-long, persistent/latent infection. Continuous immune surveillance by CMV-specific CD8+ T cells results in their accumulation over time, a process called “memory inflation”. These “inflationary” T cells migrate systemically and comprise the largest T cell populations in humans, making CMV-based vaccines attractive. Why T cells specific for only some CMV-derived epitopes undergo inflation is unclear. We found previously that recombinant murine (M)CMV expressing the SIINFEKL peptide only induced inflation of SIINFEKL-specific T cells, in contrast to wild-type MCMV infection. We show here that:

• Co-infecting mice with viruses expressing and lacking SIINFEKL enabled T cells with multiple specificities …

Competition For Antigen At The Level Of The Apc Is A Major Determinant Of Immunodominance During Memory Inflation In Murine Cytomegalovirus Infection., Lila A Farrington, Tameka A Smith, Finn Grey, Ann B Hill, Christopher M. Snyder

Department of Microbiology and Immunology Faculty Papers

The unique ability of CMV to drive the expansion of virus-specific T cell populations during the course of a lifelong, persistent infection has generated interest in the virus as a potential vaccine strategy. When designing CMV-based vaccine vectors to direct immune responses against HIV or tumor Ags, it becomes important to understand how and why certain CMV-specific populations are chosen to inflate over time. To investigate this, we designed recombinant murine CMVs (MCMVs) encoding a SIINFEKL-enhanced GFP fusion protein under the control of endogenous immediate early promoters. When mice were infected with these viruses, T cells specific for the SIINFEKL …

Two Coiled-Coil Domains Of Chlamydia Trachomatis Inca Affect Membrane Fusion Events During Infection., Erik Ronzone, Fabienne Paumet

Department of Microbiology and Immunology Faculty Papers

Chlamydia trachomatis replicates in a parasitophorous membrane-bound compartment called an inclusion. The inclusions corrupt host vesicle trafficking networks to avoid the degradative endolysosomal pathway but promote fusion with each other in order to sustain higher bacterial loads in a process known as homotypic fusion. The Chlamydia protein IncA (Inclusion protein A) appears to play central roles in both these processes as it participates to homotypic fusion and inhibits endocytic SNARE-mediated membrane fusion. How IncA selectively inhibits or activates membrane fusion remains poorly understood. In this study, we analyzed the spatial and molecular determinants of IncA's fusogenic and inhibitory functions. Using …

Toward A Network Model Of Mhc Class Ii-Restricted Antigen Processing., Michael A Miller, Asha Purnima V Ganesan, Laurence C. Eisenlohr

Department of Microbiology and Immunology Faculty Papers

The standard model of Major Histocompatibility Complex class II (MHCII)-restricted antigen processing depicts a straightforward, linear pathway: internalized antigens are converted into peptides that load in a chaperone dependent manner onto nascent MHCII in the late endosome, the complexes subsequently trafficking to the cell surface for recognition by CD4(+) T cells (TCD4+). Several variations on this theme, both moderate and radical, have come to light but these alternatives have remained peripheral, the conventional pathway generally presumed to be the primary driver of TCD4+ responses. Here we continue to press for the conceptual repositioning of these alternatives toward the center while …

Investigating The Role For Il-21 In Rabies Virus Vaccine-Induced Immunity., Corin L Dorfmeier, Evgeni P Tzvetkov, Anthony Gatt, James P Mcgettigan

Department of Microbiology and Immunology Faculty Papers

Over two-thirds of the world's population lives in regions where rabies is endemic, resulting in over 15 million people receiving multi-dose post-exposure prophylaxis (PEP) and over 55,000 deaths per year globally. A major goal in rabies virus (RABV) research is to develop a single-dose PEP that would simplify vaccination protocols, reduce costs associated with RABV prevention, and save lives. Protection against RABV infections requires virus neutralizing antibodies; however, factors influencing the development of protective RABV-specific B cell responses remain to be elucidated. Here we used a mouse model of IL-21 receptor-deficiency (IL-21R-/-) to characterize the role for IL-21 in RABV …

Comparison Of Heterologous Prime-Boost Strategies Against Human Immunodeficiency Virus Type 1 Gag Using Negative Stranded Rna Viruses., Tessa M Lawrence, Celestine N Wanjalla, Emily A Gomme, Christoph Wirblich, Anthony Gatt, Elena Carnero, Adolfo García-Sastre, Douglas S Lyles, James P Mcgettigan, Matthias J Schnell

Department of Microbiology and Immunology Faculty Papers

This study analyzed a heterologous prime-boost vaccine approach against HIV-1 using three different antigenically unrelated negative-stranded viruses (NSV) expressing HIV-1 Gag as vaccine vectors: rabies virus (RABV), vesicular stomatitis virus (VSV) and Newcastle disease virus (NDV). We hypothesized that this approach would result in more robust cellular immune responses than those achieved with the use of any of the vaccines alone in a homologous prime-boost regimen. To this end, we primed BALB/c mice with each of the NSV-based vectors. Primed mice were rested for thirty-five days after which we administered a second immunization with the same or heterologous NSV-Gag viruses. …

Changes In Serum Interleukin-33 Concentration Before And After Treatment With Pegylated Interferon Alfa-2a Plus Ribavirin In Patients With Chronic Hepatitis C Genotype 1b Infection., Bruno Cacopardo, Marilia Rita Pinzone, Filippo Palermo, Giuseppe Nunnari

Department of Microbiology and Immunology Faculty Papers

BACKGROUND: IL-33 is a novel member of the IL-1 family, which has been shown to play an important role in T helper 2 (Th2)-associated immune responses. Recent studies have suggested a possible role for IL-33 in the pathogenesis of liver damage during acute and chronic hepatitis; furthermore, IL-33 may be involved in the development and progression of liver fibrosis.

OBJECTIVES: To evaluate serum IL-33 levels in a group of patients with chronic hepatitis C (CHC) genotype 1b at enrolment and after a course of pegylated (PEG)-IFN plus ribavirin.

PATIENTS AND METHODS: 60 patients with chronic hepatitis C (CHC) and 65 …

Immune Clearance Of Attenuated Rabies Virus Results In Neuronal Survival With Altered Gene Expression., Emily A Gomme, Christoph Wirblich, Sankar Addya, Glenn F Rall, Matthias J Schnell

Department of Microbiology and Immunology Faculty Papers

Rabies virus (RABV) is a highly neurotropic pathogen that typically leads to mortality of infected animals and humans. The precise etiology of rabies neuropathogenesis is unknown, though it is hypothesized to be due either to neuronal death or dysfunction. Analysis of human brains post-mortem reveals surprisingly little tissue damage and neuropathology considering the dramatic clinical symptomology, supporting the neuronal dysfunction model. However, whether or not neurons survive infection and clearance and, provided they do, whether they are functionally restored to their pre-infection phenotype has not been determined in vivo for RABV, or any neurotropic virus. This is due, in part, …

Effects Of Apoptotic Cell Accumulation Caused By Mer Deficiency On Germinal Center B Cells And Helper T Cells, Tahsin N. Khan, Eric B. Wong, Ziaur S.M. Rahman

Department of Microbiology and Immunology Faculty Papers

Mer (MerTK), a member of the Tyro-3/Axl/Mer subfamily receptor tyrosine kinases, expression on phagocytes facilitates their clearance of apoptotic cells (ACs). Mer expression in germinal centers (GCs) occurs predominantly on tingible body macrophages. B and T cells do not express Mer. Mer deficiency (Mer-/-) results in the accumulation of ACs in GCs and augmented antibody-forming cell (AFC), GC and IgG2 Ab responses against T-dependent (TD) Ag. Here, we show that AC accumulation in GCs and elevated AFC, GC and IgG2 Ab responses in Mer-/- mice lasted for at least 80 days after immunization with NP-OVA. Enhanced responses and AC accumulation …

A Novel Function For Snap29 (Synaptosomal-Associated Protein Of 29 Kda) In Mast Cell Phagocytosis., Jordan Wesolowski, Vernon Caldwell, Fabienne Paumet

Department of Microbiology and Immunology Faculty Papers

Mast cells play a critical role in the innate immune response to bacterial infection. They internalize and kill a variety of bacteria and process antigen for presentation to T cells via MHC molecules. Although mast cell phagocytosis appears to play a significant role during bacterial infection, little is known about the proteins involved in its regulation. In this study, we demonstrate that the SNARE protein SNAP29 is involved in mast cell phagocytosis. SNAP29 is localized in the endocytic pathway and is transiently recruited to Escherichia coli (E. coli)-containing phagosomes. Interestingly, overexpression of SNAP29 significantly increases the internalization and killing of …

Hiv Rna Suppression And Immune Restoration: Can We Do Better?, Marilia Rita Pinzone, Michelino Di Rosa, Bruno Cacopardo, Giuseppe Nunnari

Department of Microbiology and Immunology Faculty Papers

HAART has significantly changed the natural history of HIV infection: patients receiving antiretrovirals are usually able to control viremia, even though not all virological responders adequately recover their CD4+ count. The reasons for poor immune restoration are only partially known and they include genetic, demographic and immunologic factors. A crucial element affecting immune recovery is immune activation, related to residual viremia; indeed, a suboptimal virological control (i.e., low levels of plasma HIV RNA) has been related with higher levels of chronic inflammation and all-cause mortality. The sources of residual viremia are not yet completely known, even though the most important …

Evidence That The Density Of Self Peptide-Mhc Ligands Regulates T-Cell Receptor Signaling., Nadia Anikeeva, Dimitry Gakamsky, Jørgen Schøller, Yuri Sykulev

Department of Microbiology and Immunology Faculty Papers

Noncognate or self peptide-MHC (pMHC) ligands productively interact with T-cell receptor (TCR) and are always in a large access over the cognate pMHC on the surface of antigen presenting cells. We assembled soluble cognate and noncognate pMHC class I (pMHC-I) ligands at designated ratios on various scaffolds into oligomers that mimic pMHC clustering and examined how multivalency and density of the pMHCs in model clusters influences the binding to live CD8 T cells and the kinetics of TCR signaling. Our data demonstrate that the density of self pMHC-I proteins promotes their interaction with CD8 co-receptor, which plays a critical role …