HIV 101: Fundamentals of HIV Infection

HIV 101: Fundamentals of HIV Infection David H. Spach, MD Professor of Medicine University of Washington Seattle, Washington Learning Objectives After attending this presentation, learners will be able to: Summarize events of early HIV infection List the sequence of laboratory markers following HIV acquisition Describe basic mechanisms of antiretroviral therapy Fundamentals of HIV: Outline Pathogenesis of HIV Transmission and Early Infection Diagnosis and Management of Acute HIV Natural History of Untreated HIV Infection HIV Life Cycle and Mechanisms of ARV Medications

Pathogenesis of HIV Transmission and Early Infection Transmission of HIV Chronic HIV infection HIV-Negative HIV Quasispecies + - Transmission of HIV Chronic HIV infection Infection with Founder Virus + +

Sexual Transmission and Founder HIV: Prime Infection HIV Day 1 Mucous Layer X4-Tropic HIV Defective HIV Replicating R5-Tropic HIV Less Fit HIV Modified from: Keele BF, et al. Proc Natl Acad Sci U S A. 2008;105:7552-7. Host Cellular Receptors Involved in HIV Infection Host Receptors CD4 HIV CXCR4 CCR5 CD4 CCR5 CXCR4 CD4 Cell HIV Sexual Transmission Usually Caused by R5-Tropic HIV R5 HIV CD4 CD4 Intracellular Space CCR5 CXCR4 Host Cell

Local HIV Expansion HIV Day 2-4 CD4 Cell Dendritic Cell Tissue Macrophage Activated CD4 Cell Regional Lymphatic Dissemination Dendritic Cell Day 3-7 Lymph Node CD4 Cell Tissue Macrophage Early Hematogenous Spread Day 7-10

Acute HIV: Eclipse Phase Eclipse Phase 10,000,000 HIV RNA (copies/ml) 1,000,000 100,000 10,000 1,000 100 10 HIV RNA Limit of Detection 1 0 5 10 15 20 25 30 35 40 45 50 Days following HIV Acquisition Early Damage to Gut-Associated Lymphoid Tissue (GALT) CD4 cells CD8 cells Dendritic cells HIV Small Bowel Small Bowel Normal GALT HIV-Induced Damage to GALT Illustration by David Spach, MD Diagnosis and Management of Acute HIV Infection

Clinical Manifestations of Acute HIV Infection Fever Lethargy Myalgias Rash Headache Pharyngitis Adenopathy 44 59 57 55 52 74 86 N = 160 Source: Vanhems P, et al. AIDS. 2000;14:375-81. 0 10 20 30 40 50 60 70 80 90 100 Patients % Acute HIV: Seroconversion Window Period Seroconversion Window Period 30 25 20 15 Antibody Titer 0 5 10 15 20 25 30 35 40 45 50 Days Following HIV Acquisition 10 Acute (Primary) HIV: Symptomatic Disease 10,000,000 Acute Illness 30 HIV RNA (copies/ml) 1,000,000 100,000 10,000 1,000 100 10 25 20 15 Antibody Titer 1 10 0 5 10 15 20 25 30 35 40 45 50 Days Following HIV Acquisition

Laboratory Diagnosis of Acute HIV Acute Illness HIV Antibody HIV RNA 0 5 10 15 20 25 30 35 40 45 50 Days Following HIV Acquisition HIV p24 antigen Acute HIV: Diagnosis HIV-1/2 Antigen/Antibody Immunoassay + HIV-1/HIV-2 Ab Differentiation Immunoassay HIV-1 (-) HIV-2 (-) HIV-1 NAT + Early HIV Infection and Test Reactivity HIV RNA 4 th Generation Antigen-Antibody Lab Rapid Lab 3rd Generation Antibody Rapid Western Blot 0 5 10 15 20 25 30 35 40 45 50 Days following HIV Acquisition

Acute HIV Diagnosis (Very Early Infection) HIV-1/2 Antigen/Antibody Immunoassay - HIV-1/HIV-2 Ab Differentiation Immunoassay HIV-1 NAT Source: Centers for Disease Control and Prevention. January, 2018. + Acute (Primary) HIV: High Transmission Risk + Acute (Primary) HIV: High Transmission Risk Unaware of HIV status High viral load Low titers of neutralizing antibodies + Homogeneity of transmission-capable HIV

Acute HIV: Partner Notification Extremely Important + - + - + - Acute HIV Treatment: Urgency to Treat Minimize immune damage Limit infection of latent reservoir pool Prevent high risk forward transmission of HIV Treatment of Acute HIV ARS Question A 23-year old man is diagnosed with acute HIV, with an HIV RNA level of 324,000 copies/ml. An HIV genotypic drug resistance test is ordered. The decision is made to start treatment now.

Acute HIV Treatment: Adult and Adolescent ARV Guidelines Treatment recommended for all with acute HIV Order HIV genotypic drug resistance test prior to treatment Can initiate ART before results of resistance test available Recommended Regimens (Rating AIII) - Boosted-Darunavir + (TDF-FTC or TAF-FTC) - Dolutegravir + (TDF-FTC or TAF-FTC) Modify regimen if need with drug resistance test results Source: AIDS Info. Adult and Adolescent ARV Guidelines. October 28, 2018. Natural History of Untreated HIV

Early HIV Infection and Set Point Set Point HIV RNA 0 20 40 60 80 100 120 140 160 180 200 220 Days following HIV Infection Immune Response, HIV RNA Levels, and Progression Not Receiving Antiretroviral Therapy Weak CTL Response Rapid Progression Moderate CTL Response Moderate Progression HIV RNA Time (Following HIV Infection) Strong CTL Response Slow Progression Source: Walker BD, Goulder PJ. Nature 2000;407:313-4. CD4 Cell Progression Without Antiretroviral Therapy CD4 Cell Count 1000 800 600 400 200 0 Not Receiving Antiretroviral Therapy Slow Progression Moderate Progression Rapid Progression Time (Years)

Viremic HIV Controller HIV RNA (copies/ml) 1,000,000 100,000 10,000 1,000 100 10 Not Receiving Antiretroviral Therapy 1/100 200 50 1 Year 1 0 4 8 12 (expanded) 16 20 24 28 1 2 3 4 5 6 7 8 Years HIV Elite Controllers HIV RNA (copies/ml) 1,000,000 100,000 10,000 1,000 100 10 Not Receiving Antiretroviral Therapy 1/300 50 1 0 4 8 Year 1 12 (expanded) 16 20 24 28 1 2 3 4 5 6 7 8 Years Elite and Viremic Controllers 1000 Not Receiving Antiretroviral Therapy CD4 Cell Count 800 600 400 200 Elite Controller Viremic Controller 0 0 0 0 Year 10 0 1 2 3 4 5 6 7 8 (expanded) Years

CD4 Cell Progression Without Antiretroviral Therapy CD4 Cell Count 1000 800 600 400 200 Not Receiving Antiretroviral Therapy 0 0 0 0Year 01 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 (expanded) Years CD4 Cell Progression Without Antiretroviral Therapy CD4 Cell Count 1000 800 600 400 200 Not Receiving Antiretroviral Therapy Immune Deficiency 0 0 0 0Year 01 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 (expanded) Years CD4 Cell Progression Without Antiretroviral Therapy CD4 Cell Count 1000 800 600 400 200 Not Receiving Antiretroviral Therapy Immune Activation and Inflammation 0 0 0 0 Year 0 1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 (expanded) Years

Chronic Immune Activation and Inflammation Immune Activation and Inflammation Myocardial Infarction Stroke Cancer HIV Life Cycle and Mechanism of ARV Medications HIV Life Cycle HIV HIV Nucleus CCR5 Host DNA CD4 HIV RNA HIV RNA HIV DNA HIV DNA mrna Gag Host Cell Gag-Pol

Major Antiretroviral Therapy Drug Classes Entry Inhibitor Integrase Inhibitor Protease Inhibitor HIV Nucleus HIV CCR5 Host DNA CD4 HIV RNA HIV DNA HIV RNA HIV DNA mrna Nucleoside RTI Non-Nucleoside RTI Gag-Pol Host Cell Gag Common Initial Antiretroviral Regimens Backbone Anchor Drug Integrase Inhibitor 2 Nucleoside RTIs + Protease Inhibitor (Boosted) Non-Nucleoside RTI HIV Enzymes and ARV Drug Classes Reverse Transcriptase Integrase Protease Nucleoside RTI Non-Nucleoside RTI Integrase Inhibitor Protease Inhibitor

HIV Reverse Transcription and Reverse Transcriptase Inhibitors (NRTIs and NNRTIs) HIV Reverse Transcription HIV RNA Reverse Transcriptase HIV DNA HIV Reverse Transcription: Conversion of HIV RNA to DNA Nucleotides (human) HIV DNA HIV RNA Reverse Transcriptase

HIV Reverse Transcription: Conversion of HIV RNA to DNA Nucleotides (human) Primer HIV DNA Template Reverse Transcriptase HIV RNA Inhibition of HIV Reverse Transcription: NRTI NRTI Human Nucleotides Primer HIV DNA Template Incorporation of NRTI Reverse Transcriptase HIV RNA Inhibition of HIV Reverse Transcription: NRTI NRTI Human Nucleotides Primer HIV DNA Template Reverse Transcriptase Primer Blocking HIV RNA

Inhibition of HIV Reverse Transcription: NRTI NRTI Human Nucleotides Primer HIV DNA Template Reverse Transcriptase Chain Termination HIV RNA Inhibition of HIV Reverse Transcription: NNRTI Polymerase Active Site NNRTI Binding Pocket Reverse Transcriptase Illustration: David Ehlert, CMI and David Spach, MD Inhibition of HIV Reverse Transcription: NNRTI NNRTI Inhibitor Polymerase Active Site NNRTI Binding Pocket Reverse Transcriptase Illustration: David Ehlert, CMI and David Spach, MD

Inhibition of HIV Reverse Transcription: NNRTI NNRTI Inhibitor Altered Polymerase Active Site Reverse Transcriptase Illustration: David Ehlert, CMI and David Spach, MD HIV Integration and Integrase Strand Transfer Inhibitors (INSTIs) HIV Integrase HIV Integrase Dimer C-terminal domain N-terminal domain Catalytic core domain Catalytic triad Illustration: David Ehlert, CMI and David Spach, MD

HIV Integration into Host DNA HIV DNA Integrase Integrase Host DNA HIV Integration into Host DNA HIV DNA Host DNA Host DNA HIV Integration into Host DNA: Strand Transfer HIV DNA Host DNA Host DNA

HIV Integration into Host DNA: Proviral DNA Host DNA Proviral HIV DNA Host DNA Integrase Strand Transfer Inhibitor ( Integrase Inhibitor ) Integrase Strand Transfer Inhibitor Integrase Enzyme Active Site HIV Integrase Illustration: David Ehlert, CMI and David Spach, MD Integrase Strand Transfer Inhibitor HIV DNA Integrase Strand Transfer Inhibitor Host DNA Host DNA

HIV Proteolytic Processing and Protease Inhibitor (PI) HIV Protease Open Semi-Open Closed Illustration: David Ehlert, CMI and David Spach, MD HIV Proteolytic Processing Gag-Pol Polyprotein Matrix (p17) Capsid (p24) Gag Polyprotein Matrix (p17) Capsid (p24) Nucleocapsid p6 Protease Reverse Transcriptase Integrase HIV Protease Nucleocapsid p6

HIV Maturation and Proteolytic Cleavage Gag Polyprotein HIV Protease HIV Maturation and Proteolytic Cleavage HIV Maturation and Proteolytic Cleavage

HIV Protease Inhibitor Protease Inhibitor HIV Protease HIV Protease Inhibitor Protease Inhibitor Blocked Proteolytic Cleavage Result: Immature Virion Protease Inhibitor Fundamentals of HIV: Summary Pathogenesis of HIV Transmission and Early Infection Diagnosis and Management of Acute HIV Natural History of Untreated HIV Infection HIV Life Cycle and Mechanisms of ARV Medications

Question-and-Answer

HIV 101. Fundamentals of HIV Infection David H. Spach, MD SUGGESTED READINGS Brenchley JM, Douek DC. The mucosal barrier and immune activation in HIV pathogenesis. Curr Opin HIV AIDS. 2008;3(3):356-361. Gonzalo-Gil E, Ikediobi U, Sutton RE. Mechanisms of virologic control and clinical characteristics of hiv+ elite/viremic controllers. Yale J Biol Med. 2017;90(2):245-259. Haase AT. Early events in sexual transmission of HIV and SIV and opportunities for interventions. Annu Rev Med. 2011;62:127-139. Hazuda DJ. HIV integrase as a target for antiretroviral therapy. Curr Opin HIV AIDS. 2012;7(5):383-389. Hu WS, Hughes SH. HIV-1 reverse transcription. Cold Spring Harb Perspect Med. 2012;2(10) Keele BF, Giorgi EE, Salazar-Gonzalez JF, et al. Identification and characterization of transmitted and early founder virus envelopes in primary HIV-1 infection. Proc Natl Acad Sci U S A. 2008;105(21):7552-7557. Lusic M, Siliciano RF. Nuclear landscape of HIV-1 infection and integration. Nat Rev Microbiol. 2017;15(2):69-82. Pilcher CD, Tien HC, Eron JJ, et al. Brief but efficient: acute HIV infection and the sexual transmission of HIV. J Infect Dis. 2004;189:1785-1792. Walker BD, Goulder PJ. AIDS. Escape from the immune system. Nature. 2000;407(6802):313-314.