Irini Sereti, M.D., Ph.D.

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Immunopathogenesis Section
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Program Description

The Immunopathogenesis Section investigates the cellular and molecular mechanisms underlying the immune dysfunction caused by HIV infection. Several major projects ongoing in the section are described below.

Role of HIV envelope-target cell interactions in the pathogenesis of HIV infection (Lead Investigators: James Arthos, Ph.D., and Claudia Cicala, Ph.D.)

The primary aim of this project is to better understand the role of the HIV envelope protein in HIV pathogenesis. To that end, we have focused on the complex interplay between the viral envelope and several of the known cell surface receptors to which it binds (CD4, CCR5, CXCR4, integrin α4β7). Understanding the complexities and significance of the signaling processes that gp120 mediates will enhance our understanding of HIV-1 pathogenesis and may facilitate the discovery of new strategies for the treatment and prevention of HIV-1 disease. The finding that gp120 engages integrin α4β7, the gut-homing receptor, opens up many new and potentially important questions. Because α4β7 mediates leukocyte homing to gut-associated lymphoid tissue (GALT), which is a principal site of HIV replication during the acute phase of infection, we explored the role of α4β7-expressing CD4+ T cells in HIV transmission. We previously determined that human α4β7high CD4+ T cells are highly susceptible in vitro to productive infection by HIV, in part because α4β7high CD4+ T cells are enriched with metabolically active cells. We then tested this hypothesis in a non-human primate in vivo model of HIV/SIV infection and determined that an antibody specific for α4β7 prevented transmission in a rhesus macaque model of mucosal transmission. In addition, we have investigated the interaction between HIV and α4β7 on primary B cells. We have learned that some of the defects associated with HIV disease result from direct interactions between gp120 and receptors on B cells. These findings have relevance to our understanding of early HIV transmission and viral dissemination, particularly in GALT, providing new avenues of investigation regarding the potential role of α4β7+ as a therapeutic target against HIV infection.

Major Findings

  • HIV-1 envelope binds to, and signals through α4β7 integrin, the gut mucosal homing receptor for peripheral T cells.
  • The HIV envelope protein gp120 binds to a conformationally active form of α4β7 on CD4+ T cells. This binding is independent of the binding of envelope to the CD4 molecule. Because the function of α4β7 is intimately linked to GALT, where HIV replicates at high levels especially in acute/early infection, the specific affinity observed suggests that envelope-α α4β7 interactions play an important role in HIV pathogenesis.
  • α4β7high CD4+ T cells are more susceptible to productive infection by HIV than are α4β7low/neg CD4+ T cells, in part because this cellular subset is enriched with metabolically active cells.
  • Removal of N-linked glycosylation sites in HIV envelopes results in large increases in the specific affinity of gp120 for α4β7. Several envelopes derived from viruses isolated shortly after transmission react with α4β7 to a substantially higher level than do the great majority of envelopes derived from viruses isolated in the chronic phase of infection. These results suggest that mucosal transmission may frequently involve a relative requirement for the productive infection of α4β7+ CD4+ T cells.
  • Targeting α4β7 significantly reduces intravaginal mucosal transmission and subsequent tissue dissemination of SIV in a non-human primate model of HIV/AIDS. This supports our hypothesis that α4β7+/CD4+ T cells can play an important role in mucosal transmission of HIV.
Selected Publications

Fauci AS, Marston HD. Ending the HIV-AIDS Pandemic--Follow the Science. N Engl J Med. 2015 Dec 3;373(23):2197-9.

Fauci AS, Marston HD. Toward an HIV vaccine: A scientific journey. Science. 2015 Jul 24;349(6246):386-7.

Chun TW, Moir S, Fauci AS. HIV reservoirs as obstacles and opportunities for an HIV cure. Nat Immunol. 2015 Jun;16(6):584-9.

Kardava L, Moir S, Shah N, Wang W, Ho J, Wilson R, Buckner CM, Santich BH, Kim LJY, Spurlin EE, Nelson AK, Wheatley AK, Harvey CJ, McDermott AB, Wucherpfennig KW, Chun TW, Tsang JS, Li Y, Fauci AS. Abnormal B cell memory subsets dominate HIV-specific responses in infected individuals. J Clin Invest. 2014 Aug;124(8):3352-63.

Byrareddy SN, Kallam B, Arthos J, Cicala C, Nawaz F, Hiatt J, Kersh EN, McNicholl JM, Hanson D, Reimann KA, Brameier M, Walter L, Rogers K, Mayne AE, Dunbar P, Villinger T, Little D, Parslow TG, Santangelo PJ, Villinger F, Fauci AS, Ansari AA.Targeting α4β7 integrin reduces mucosal transmission of simian immunodeficiency virus and protects gut-associated lymphoid tissue from infection. Nat Med. 2014 Dec;20(12):1397-400.

Jelicic K, Cimbro R, Nawaz F, Huang da W, Zheng X, Yang J, Lempicki RA, Pascuccio M, Van Ryk D, Schwing C, Hiatt J, Okwara N, Wei D, Roby G, David A, Hwang IY, Kehrl JH, Arthos J, Cicala C, Fauci AS. The HIV-1 envelope protein gp120 impairs B cell proliferation by inducing TGF-β1 production and FcRL4 expression. Nat Immunol. 2013 Dec;14(12):1256-65.

Visit PubMed for a complete publication listing.

Additional Information

Patents

Arthos J, Good D, Cicala C, Fauci AS, inventors; The United States of America, as represented by the Secretary, Department of Health and Human Services, assignee. Use of antagonists of the interaction between HIV GP120 and A4B7 integrin. United States patent US 9,193,790. 2015 Nov 24.

Arthos J, Cicala C, Fauci AS, inventors; The United States of America as represented by the Department of Health and Human Services, assignee. Fusion protein including of CD4. United States patent US 7,368,114. 2008 May 6.

Scala G, Chen X, Cohen OJ, Fauci AS, inventors; The United States of America as represented by the Secretary of the Department of Health and Human Services, assignee. HIV related peptides. United States patent US 6,911,527. 2005 Jun 28.

Lane HC, Kovacs JA, Fauci AS, inventors; The United States of America as represented by the Department of Health and Human Services, assignee. Immunologic enhancement with intermittent interleukin-2 therapy. United States patent US 6,548,055. 2003 Apr 15.

Lane HC, Kovacs JA, Fauci AS, inventors; The United States of America as represented by the Department of Health and Human Services, assignee. Immunologic enhancement with intermittent interleukin-2 therapy. United States patent US 6,190,656. 2001 Feb 20.

Lane HC, Kovacs JA, Fauci AS, inventors; The United States of America as represented by the Department of Health and Human Services, assignee. Immunologic enhancement with intermittent interleukin-2 therapy. United States patent US 5,696,079. 1997 Dec 9.

Visit the U.S. Patent and Trademark Office for a complete patent listing.

Major Areas of Research
  • Role of HIV envelope signaling in viral replication and immune dysfunction
  • Novel approaches to the inhibition of HIV binding and entry into CD4+ T cells

Safety and Immunogenicity of Stabilized CH505 TF chTrimer Vaccination in Adults Living With HIV-1 on Suppressive Antiretroviral Therapy

The objective of this study is to assess the safety, tolerability, and immunogenicity of a vaccination with stabilized CH505 TF chTrimer admixed with 3M-052-AF + Aluminum hydroxide (Alum), to assess the effect of CH505 TF chTrimer vaccine as a therapeutic vaccine in adults living with HIV-1 on suppressive antiretroviral therapy (ART) with the aim of inducing new HIV-1 Envelope (Env) B-cell neutralizing immune responses.

Contact Information

Office/Contact: Aleen Khodabakhshian
Phone: 310-557-3798
Email: akhodabakhshian@mednet.ucla.edu
 

Preclinical Models of Infectious Disease Microphysiological Systems (MPS)

NIAID provides preclinical services using human cell-based MPS and organoids to test promising therapeutic candidates that combat viruses of biodefense (pandemic) concern.

Topical Steroid Withdrawal Diagnostic Criteria Defined by NIH Researchers

Topical steroid withdrawal (TSW) results in dermatitis that is distinct from eczema and is caused by an excess of NAD+, an essential chemical compound in the body, according to a new study from NIAID researchers.

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Omalizumab Treats Multi-Food Allergy Better than Oral Immunotherapy

The high rate of allergic reactions and other intolerable side effects of oral immunotherapy in the NIH-funded trial explained the superiority of omalizumab.

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NIH-Funded Clinical Trial Will Evaluate New Dengue Therapeutic

A Phase 2 clinical trial will test the safety and efficacy of an experimental treatment for dengue, a viral disease transmitted by mosquitoes.

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Therapy Helps Peanut-Allergic Kids Tolerate Tablespoons of Peanut Butter

Eating slowly increasing amounts of peanut butter enabled 100% of kids with peanut allergy to consume 3 tablespoons of peanut butter without an allergic reaction.

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Measuring Innovation: Laboratory Infrastructure to Deliver Essential HIV Clinical Trial Results

NIAID Now |

This blog is the fifth in a series about the future of NIAID's HIV clinical research enterprise. For more information, please visit the HIV Clinical Research Enterprise page.

The outcomes of HIV clinical trials are often determined by precisely and accurately measuring how specific interventions work biologically in people. Whether tracking immune responses to a preventive vaccine candidate, monitoring changes to the amount of virus in the body, or screening for certain adverse events after administering a novel therapeutic, study teams routinely interact with clinical trial participants to safely obtain, store, transport, and analyze tissue and bodily fluid samples to answer important scientific questions about the impact of an HIV intervention in a laboratory. High quality, reliable laboratory infrastructure is critical to the accuracy and validity of clinical trial results. 

More than 150 NIAID-supported laboratories in 20 countries are addressing the diverse scientific programs of the four clinical trials networks in the Institute’s HIV clinical research enterprise. Since the start of HIV clinical research, laboratory capacities have grown in scope to support an increasing number of global clinical trials, emerging complexities in study protocol design and laboratory testing demands and evolving regulatory requirements for research and licensure.

NIAID is engaging research partners, community representatives, and other public health stakeholders in a multidisciplinary evaluation of its HIV clinical trials networks’ progress toward short- and long-term scientific goals. This process assesses knowledge gained since the networks were last awarded in 2020 to identify an essential path forward based on the latest laboratory and clinical evidence. Future NIAID HIV clinical research investments build on the conclusions of these discussions. 

In the next iteration of HIV clinical trials networks, laboratory functions will continue to evolve to align with scientific priorities and research approaches. Networks will support small early-phase trials, large registrational trials and implementation science research to examine preventive vaccine candidates and non-vaccine prevention interventions, antiviral treatments, HIV curative strategies, and therapies to improve the clinical outcomes of people affected by and living with HIV. Selected studies also will rely on high quality laboratory resources to examine interventions for tuberculosis, hepatitis, mpox and other infectious diseases. Clinical trial networks will need to employ a variety of laboratory types to achieve these objectives.  To increase flexibility and ensure the timeliness and the high quality standards the HIV field relies on for evidence that informs science, licensure and equitable practice, NIAID will have the ultimate authority for laboratory selection and approval.

Efficiency and Versatility 

Laboratory assays for HIV clinical trials continue to expand in quantity and complexity and require proportionate technical expertise and management. Future clinical research needs will include immunologic, microbiologic, and molecular testing, as well as standard chemistries and hematologic assays, with fluctuating volumes across a global collection of research sites. Balancing capacity, efficiency, scalability, and cost will require a mixed methods approach. These may include centralized laboratory testing where feasible and advantageous for protocol-specified tests; standardized processes for rapid assessment and approval of new network laboratories; and validated third-party outsourcing of routine assays to ensure timely turnaround when demands surge. 

Quality and Standardization

Ensuring consistent laboratory operations and high quality laboratory data will require continued compliance with the NIAID Division of AIDS Good Clinical Laboratory Practices and other applicable regulatory guidelines, ongoing external quality assurance monitoring, strong inventory management, importation and exportation expertise, and data and specimen management.

The research community plays an essential role in shaping NIAID’s scientific direction and research enterprise operations. We want to hear from you. Please share your questions and comments at NextNIAIDHIVNetworks@mail.nih.gov.

About NIAID’s HIV Clinical Trials Networks

The clinical trials networks are supported through grants from NIAID, with co-funding from and scientific partnerships with NIH’s National Institute of Mental Health, National Institute on Drug Abuse, National Institute on Aging, and other NIH institutes and centers. There are four networks—Advancing Clinical Therapeutics Globally for HIV/AIDS and Other Infections, the HIV Vaccine Trials Network, the HIV Prevention Trials Network, and the International Maternal Pediatric Adolescent AIDS Clinical Trials Network.

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NIH Officials Assess Threat of H5N1

HPAI H5N1 influenza remains a low risk to most Americans, but that does not diminish concern about the virus, NIAID experts say.

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A Biorepository of Multiple Allergic Diseases (MADREP) With Longitudinal Follow-Up

To create a repository of clinical, laboratory, and diagnostic data and specimens from a cohort of suspected or confirmed atopic or allergic individuals with diverse disorders seen by allergist-immunologists and rhinologists.

Contact Information

Office/Contact: NIH Clinical Center Office of Patient Recruitment (OPR)
Phone: 800-411-1222
TTY: TTY dial 711
Email: ccopr@nih.gov