Isaac R. Rodriguez-Chavez, Ph.D., M.S., M.H.S.Director, AIDS and Immunosuppression Program, NIDCR, USA

Emerging and Re-emerging Research and Issues on Oral

Aspects of HIV/AIDS

Overview1. The biology of HIV transmission2. HIV virology and oral viral pathogenesis3. Pathogenesis of oral opportunistic infections4. Oral HIV pathogenesis connected with metabolic,

nutritional and body composition change5. Pathogenesis of AIDS-related oral malignancies6. Oral pathogenesis of HIV and neurological

manifestations7. Oral mucosal HIV vaccines8. HIV diagnostics

Emerging and Re-emerging Issues on Oral Aspects of HIV/AIDS

Topic 1: The Biology of HIV Transmission

Goal: To determine viral, genetic and immune mechanisms involved in oral HIV transmission and the establishment and spread of HIV infection.

• Role of phenotype/genotype/fitness/variants in oral transmission of HIV• Mechanisms of virus- and host-encoded genes/products and

their interactions• Role of the oral microbiome, viriome and fugizome in

transmission, establishment, spread, and exacerbation of lesions• Characterize target cell subsets for HIV entry, dissemination and

replication at different stages of replication

Topic 1: The Biology of HIV Transmission (continued)

• Determine mechanisms by which oral innate and mucosal immunity interplay with systemic immunity and how they are influenced by genetic and environmental factors to modulate HIV replication, transmission, establishment and spread• Saliva soluble factors, cellular and humoral components• HLA polymorphisms –B*27, B*57

• Assess the role of inflammation and its mediators in the oral cavity, impacting HIV transmission and dissemination

Topic 2: HIV Virology and Oral Viral Pathogenesis

Goal: To determine viral and host mechanisms in the oral cavity linked with HIV induced immune dysfunction, abnormal immune activation, inflammation and disease progression

• Define factors and mechanisms that regulate initial HIV replication, blocking and/or controlling virus during 1ry infection, establish viral setpoint and disease progression

• Determine early events of HIV infection in the oral cavity connected with systemic spread and later clinical course

• Define virologic and host factors in the oral cavity that enable HIV to establish and maintain persistent infection

• Delineate molecular mechanisms by which virus-encoded gene products, host cellular factors, and intracellular compartments regulate HIV replication and influence oral pathogenesis

Topic 2: HIV Virology and Oral Viral Pathogenesis (continued)

• Determine the factors that influence the identification and susceptibility of target cells in the oral cavity to HIV infection and their ability to support HIV replication

• Determine the structures of complexes between viral proteins and saliva soluble factors involved in the process that block HIV infection

• Define mechanisms underlying HIV induced depletion and dysfunction of immune cells in the oral cavity• T, NK, DC, B, MØ loss/impairment, cell death,

nonresponsiveness, dysregulation, altered production of factors, regeneration and homeostasis of cell populations

• Define the role and mechanisms of immune activation and inflammation (IRIS) in the oral cavity to HIV disease progression

Topic 2: HIV Virology and Oral Viral Pathogenesis (continued)

• Evaluate whether and to what extend viral-induced damage to the oral mucosal immune system can be reversed following suppression of HIV replication by therapy

• Define viral and host markers and develop assays to study oral innate and mucosal immunity in the context of HIV

• Study oral reservoirs (MØs) of HIV that permit persistence in the setting of therapy and ongoing immune responses

• Define the viral and host factors associated with clinical response/lack of response to oral therapy in infected subjects

Topic 3: Pathogenesis of Oral Opportunistic Infections

Goal: To elucidate the pathogenic mechanisms and consequences of opportunistic infections (OIs) and co-infections in HIV-infected individuals and the factors that regulate susceptibility to OIs that may be targeted for prevention

• Conduct studies on oral pathogens and their interactions with the host

• Determine genetic and environmental risk factors associated with susceptibility to, the development of, and the progression of oral OIs in HIV infected individuals

• Study the effects of oral OIs and co-infections on immune dysfunction, impact on nutritional status and progression

• Define mucosal immune responses to oral OIs and determine how they may be altered by HIV infection/ART

Topic 3: Pathogenesis of Oral Opportunistic Infections (continued)

• Study how HIV infection changes the pathogenesis of co-infecting oral pathogens

• Elucidate mechanisms of immune function that mediate protection against oral OIs

• Study the effects of HIV therapy-associated immune reconstitution on the clinical course and manifestation of oral OIs and co-infections

• Use of metagenomics analyses to characterize oral microbiome, viriome and fungizome and their alterations due to oral OIs, impacting HIV infection and progression

• Determine biomarkers and factors associated with clinical response and lack of response to oral therapy against OIs and co-infections in HIV infected subjects

Topic 4: Oral HIV Pathogenesis Connected with Metabolic, Nutritional and Body

Composition Change

Goal: To define the etiology, oral pathophysiology, consequences of HIV infection and treatment-related metabolic disorders, body composition changes, nutritional status, endocrine dysfunction, oral health status and cardiovascular disease in HIV infected subjects

• Define mechanisms underlying alterations in metabolism, body composition, nutritional status, endocrine function, growth and development, and the risks of developing oral manifestations in HIV infected subjects

• Study the impact of HIV on aging populations, including implications of HIV infection for oral disease.

• Use novel therapies that suppress HIV infection to explore the pathogenic mechanisms underlying alterations in metabolism, body composition, nutritional status, growth, development and oral disease

• Define factors tied with clinical response (or lack of) to oral therapy linking metabolic, nutritional and body composition change with oral health and/or disease

Goal: To elucidate the etiologic factors, co-factors, pathogenesis, and consequences of HIV-related oral malignancies

• Elucidate the immune defects and host factors in HIV infection that predispose to the development of oral malignancies

• Elucidate the mechanisms by which HIV infection and its treatment enhance the development of oral malignancies

• Identify the mechanisms by which immune dysfunction, oncogenes, suppressor genes, carcinogens and non-HIV viral and other microbial genes and proteins contribute to oral malignancies

• Conduct studies on the biology of pathogens causing oral malignancies and their interaction with the oral cavity – mechanisms

• Investigate the contribution of HIV-associated or opportunistic-pathogen-associated inflammatory pathways and immune dysregulation to oral cancers

• Determine the impact of AIDS-associated oral malignancies on the immune response to HIV

Topic 5: Pathogenesis of AIDS-related Oral Malignancies

Goal: To elucidate the mechanisms of HIV-associated neurological disease and neurobehavioral dysfunction linked with oral health status

• Determine the impact and relationship between poor oral health status and the development of CNS manifestations, including neuropathies and dementia in the context of HIV infection

• Define if oral viral reservoirs (MØs) play a role in the neuropathogenesis of HIV/AIDS – mechanisms

• Define mechanisms of immunologic control of HIV, oral OIs and co-infections in the CNS

• Define mechanisms of immune reconstitution syndrome in the CNS in the setting of oral OIs and co-infections

• Determine the role of oral OIs, co-infections, and therapy in neurologic and neurobehavioral complications of AIDS

Topic 6: Oral Pathogenesis of HIV and Neurological Manifestations

Goal: To develop prophylactic oral mucosal HIV vaccines to help boost local and systemic immunity against HIV infection

Determine the mechanisms linking oral mucosal and innate immunity with systemic adaptive immunity

Develop HIV vaccine antigens in oral expression vectors that are stable in the oral cavity and have the ability to trigger anti-HIV protective immunity

Define the role of oral DC and NK cell subset changes during disease progression or upon oral mucosal HIV vaccination

Determine DC-NK cross-talk in the oral cavity and relationship to systemic adaptive immunity upon oral mucosal HIV vaccination

Topic 7: Oral Mucosal HIV Vaccines

Determine similarities and differences between DC-NK cross-talk in the oral mucosal site compared with other mucosal sites

Characterize soluble defense molecules produced in oral secretions upon oral mucosa HIV vaccination

Develop oral mucosal vaccine strategies that  will  induce sustained high levels of broadly reactive neutralizing antibodies to primary isolates at oral as well as other mucosal sites of infection such as the rectum and vagina

Define methodologies to increase or mobilize antigen presenting cells (e.g., immature DCs) to oral mucosal vaccination sites

Topic 7: Oral Mucosal HIV Vaccines (continued)

Understand the mechanisms involved in maintaining the balance between inductive vaccine responses and tolerance to facilitate the development of oral mucosal vaccines against HIV

Develop approaches to enhance and characterize HIV vaccine-induced immunologic memory and long term protection to oral mucosal vaccination

Harness innate immunity and regulatory T cell responses together for development of an oral mucosal vaccine

Develop and validate adjuvants (TLR ligands, fusogens, cytokines, etc) that will improve the immunogenicity of oral mucosal vaccines

Elucidate approaches to enhance and characterize HIV vaccine-induced immunologic memory and long term protection to oral mucosal vaccination

Topic 7: Oral Mucosal HIV Vaccines (continued)

Why might mucosal immunity be important for HIV vaccines?

HIV acquisition: Most HIV infections sexually transmitted. Mucosal immunity could protect against acquisition.

HIV disease progression: CD4+ CCR5+ effector memory T cells destroyed early in HIV infection. Clinic course may be ameliorated by protecting these cells at mucosal surfaces (e.g. gut mucosal T cells).

HIV transmission: HIV viral load predicts transmission to new partners. Local effects at genital, rectal and oral mucosa may lower VL in semen, vagina, gut and the oral cavity and reduce onward transmission.

Type I and II mucosae: different tissue architecture of potential vaccination sites

Immune responses can occur at distal sites due to lymphocyte homing

Holmgren & Czerkinsky, Nature Med 2005

Nasal immunization: systemic and mucosal immunity comes with safety concerns

Advantage

Strong responses in blood, large bowel, cervix/vaginaa

Safety concerns

Retrograde axonal transport of virus in olfactory nerve or CNS in mice.b,c

Cholera toxin (CT) and CTB given intranasally found in olfactory nerve/ bulb in mice. Tetanus toxoid found in olfactory nerve when given with CT.d

NALT is not found in humans

aNeutra and Kozlowski. Nat Rev Imm. 2006 b Kuo et al, Brain Research 1995 cLemiale et al. JV 2003 dGinkel et al, J Immunol 2000

Lymphatic tissue of Waldeyer’s ring, a potential vaccination site

Putative scheme for B cell homing from tonsils

Upper airwaysLacrimal and

Salivary glands

Systemic Immune System

Uterine Cervix

Mucosa

LargeBowel

Mucosa

SmallBowel

Mucosa

Peripheral bloodcirculation

GALTPeyer’s Patches

NALTWaldeyer’s Ring

Goal: To develop novel assays for HIV diagnostics with multiple uses, including: screening and confirmatory tests; central clinical/research/back up/diagnostic labs; and field applications

• EIAs –antigen and antibody combination• Rapid tests• Point of care devices• NAT and high throughput screening – multiplex assays,

microarrays, deep sequencing methods

Topic 8: HIV Diagnostics

Lateral Flow Assay Format

Microfluidic Chip Development

• Where would you contribute to help solve the emerging and re-emerging issues on oral aspects of HIV/AIDS?

Question?

• NIH, OD, OAR – Etiology and Pathogenesis• Drs. Ann Duerr and Daniel Malamud• NIDCR

Acknowledgement