1. Human Immunodeficiency Virus (HIV)
Gayane Arutunyan
Monica Brown
David Yang

2. Patient 28 year old male Bad case of thrush (oral candidiasis)
Low grade fever
Lost 20 pounds in the last year without dieting
Serious bouts of diarrhea
Stool Sample tested positive for Giardia lamblia.
Difficulty breathing
Radiographic examination showed bilateral infiltrate (characteristic of Pneumocystosis carinii pneumonia)
Stool samples tested due to diarrhea, showed positive for Giardia lamblia.
Difficulties breathing led us administer a radiographic examination, which showed bilateral infiltrate in the lungs (character of P. carinii pneumonia)
P. carinii pneumonia is an indicator of a compromised immune system. Individuals with normal immune systems do not usually get this type of pneumonia.
Biggest indicator may be the sharing of needles with other heroin addicts.
(slide may be divided into 2 slides)

3. Radiographic Results
(A.D.A.M., 2006)

4. Patient 28 year old male Bad case of thrush (oral candidiasis)
Low grade fever
Lost 20 pounds in the last year without dieting
Serious bouts of diarrhea
Stool Sample tested positive for Giardia lamblia.
Difficulty breathing
Radiographic examination showed bilateral infiltrate (characteristic of Pneumocystosis carinii pneumonia)
Heroin addict and admits to sharing needles at a “shooting gallery”
Stool samples tested due to diarrhea, showed positive for Giardia lamblia.
Difficulties breathing led us administer a radiographic examination, which showed bilateral infiltrate in the lungs (character of P. carinii pneumonia)
P. carinii pneumonia is an indicator of a compromised immune system. Individuals with normal immune systems do not usually get this type of pneumonia.
Biggest indicator may be the sharing of needles with other heroin addicts.
(slide may be divided into 2 slides)

5. Human Immunodeficiency Virus (HIV)
Icosahedral or Wedge-shaped Nucleocapsid
gp120
gp160
gp41
Reverse Transcriptase
From our initial diagnosis of the patient’s symptoms and lifestyle, we are led to believe that the patient may be infected with HIV. (ref. #12 of picture reference)
single stranded (+) sense RNA
Lipid Membrane
(NIH, 2005)

6. HIV genome
Two copies (+) ss RNA
(Dimmock, et. al, 2007)

7. Types of HIV Two species of HIV infect humans: HIV-1 HIV-2
More virulent, relatively easy to transmit
Majority of HIV infections globally
3 types of HIV-1: (based on alterations in env gene)
Clades M, N, and O
HIV-2
Less transmittable
Largely confined to West Africa
Gao, F., Bailes, E., Robertson, D. L., Chen, Y., Rodenburg, C. M., Michael, S. F., Cummins, L. B., Arthur, L. O., Peeters, M., Shaw, G. M., Sharp, P. M., and Hahn, B. H. (1999). "Origin of HIV-1 in the Chimpanzee Pan troglodytes troglodytes". Nature 397 (6718): doi: / PMID
Keele, B. F., van Heuverswyn, F., Li, Y. Y., Bailes, E., Takehisa, J., Santiago, M. L., Bibollet-Ruche, F., Chen, Y., Wain, L. V., Liegois, F., Loul, S., Mpoudi Ngole, E., Bienvenue, Y., Delaporte, E., Brookfield, J. F. Y., Sharp, P. M., Shaw, G. M., Peeters, M., and Hahn, B. H. (2006). "Chimpanzee Reservoirs of Pandemic and Nonpandemic HIV-1". Science Online doi: /science
Reeves, J. D. and Doms, R. W (2002). "Human Immunodeficiency Virus Type 2". J. Gen. Virol. 83 (Pt 6): PMID
Thomson, M. M., Perez-Alvarez, L. and Najera, R. (2002). "Molecular epidemiology of HIV-1 genetic forms and its significance for vaccine development and therapy". Lancet Infect. Dis. 2 (8): PMID
(Gao, et. al; 1999)
(Keele, et. al; 2006)
(Reeves, et. al; 2002)
(Thompson, et. al; 2002)

9. Laboratory Tests Enzyme Linked Immunosorbent Assay (ELISA)
Direct : Tests for the virus
Indirect : Tests for antibodies to the virus
Enzyme Linked Immunosorbent Assay (ELISA)
Direct : Tests for the virus
Indirect : Tests for antibodies to the virus
We will administer the Indirect ELISA to confirm our preliminary diagnosis. If ELISA results prove positive, we will confirm our results using Indirect Western Blot Analysis.

10. Indirect ELISA Rinse Rinse HIV Antigen Patient’s serum No Color Change
Enzyme-labeled
antihuman IgG

11. Laboratory Tests Enzyme Linked Immunosorbent Assay (ELISA)
Direct : Tests for the virus
Indirect : Tests for antibodies to the virus
Western Blot Analysis
Direct : analyze samples for specific protein(s)
Indirect : analyze samples for antibodies against a specific protein(s)
Enzyme Linked Immunosorbent Assay (ELISA)
Direct : Tests for the virus
Indirect : Tests for antibodies to the virus
Western Blot Analysis
Direct : analyze samples for specific protein(s)
Indirect : analyze samples for antibodies against a specific protein(s)
We will administer the Indirect ELISA to confirm our preliminary diagnosis. If ELISA results prove positive, we will confirm our results using Indirect Western Blot Analysis.

12. Indirect Western Blot Analysis

13. HIV – Western Blot Results
gp160 = viral envelope precursor (env)
gp120 = viral envelope protein binds to CD4
p31 = reverse transcriptase (pol)
p24 = viral core protein (gag)
HIV (+) serum
HIV (-) serum
(Univ. of Arizona, 1996)

14. Patient Risk Assessment
High Risk Behaviors:
Sharing of infected drug injection needles/syringes
Accidental needle stick (healthcare professionals)
Unprotected sex with infected individual
Blood transfusions/Organ transplants
Rare, only occurs in underdeveloped countries with inadequate blood donor testing programs
Transmission from infected mother-to-fetus during pregnancy or delivery
Transmission from breast milk of infected mother to her baby
With the positive test results, we conclude that our patient is infected with HIV. Risk assessment of our patient’s lifestyle matches those categorized as “high risk behaviors”.

16. Prevention of HIV Infection
Known Methods of Preventing HIV Infection:
Avoid sexual contact with infected individuals
Avoid sharing needles/syringes that could be contaminated with HIV
Avoid any type of contact with the bodily fluid of an infected individual

17. Prevention of HIV Infection
New Methods for Prevention of HIV:
Intravaginal lime or lemon juice to kill the HIV virus before entry
Intravaginal oestrogen: Karotinizing the vagina with estrogen
Male circumcision: Removal of the inner foreskin removes the main site of HIV entry into the penis, resulting in a sevenfold reduction in susceptibility to infection
Post-coital penile hygiene: Wiping the penis immediately after intercourse with lime or lemon juice or vinegar should kill the virus before it has had a chance to infect.
Discuss clinical results and how these methods can be used in the US, but especially in developing nations to prevent the spread of HIV

18. Immunological Basis for Opportunistic Infection
HIV targets cells that express CD4 and can infect macrophages, dendritic cells, and activated T cells
During the non-symptomatic phase of HIV infection, HIV has a low affinity towards T cells and higher affinity towards macrophages → slow death rate of T cells
Once the virus becomes lymphotropic, it begins to infect activated T cells far more efficiently due to increased affinity for CD4
Functional T cell levels begin to decrease, eventually to a point where the T cell population is too small to recognize the full range of Ags that could potentially be detected
The lack of full Ag recognition → core symptoms of acquired immune deficiency syndrome (AIDS). CD4 T cell depletion during AIDS allows various pathogens to escape T cell recognition, thus allowing opportunistic infections that would normally elicit a helper T cell response to bypass the immune system

19. Immunological Basis for Opportunistic Infection
Nef protein – advances the endocytosis and degradation of cell surface proteins, including CD4 and MHC proteins
Downregulates expression of host CD4
Downregulates expression of host MHC class I molecules
MHC class I molecules function to present peptide fragments to cytotoxic T cells to destroy virally infected cells.
Induces phosphorylation of MA proteins to increase viral infectivity (increased viral replication)
MA and Vpr proteins aid in facilitating the transport of HIV pre-integration complex across nuclear membrane.
Alter T cell signaling to promote viral replication.
HIV has several proteins which act to decrease host defense and increase viral infectivity, one of which is the Nef protein.
On T cells, CD4 is the co-receptor for the T cell receptor (TCR). It amplifies the signal generated by the TCR by recruiting the tyrosine kinase lck that is essential for activating many molecules involved in the signaling cascade of an activated T cell.
CD4 is also a primary receptor used by HIV-1 to gain entry into host T cells.
The HIV-1 virus attaches to CD4 with a particular protein in its viral envelope known as gp120. The binding to CD4 creates a shift in the conformation of the viral gp120 protein allowing HIV-1 to bind to two other cell surface receptors on the host cell (the chemokine receptors CCR5 and CXCR4). Following another change in shape of a different viral protein (gp41), HIV inserts a fusion peptide into the host T cell that allows the outer membrane of the virus to fuse with the T-cell membrane.
HIV infection leads to a progressive reduction in the number of T cells possessing CD4 receptors and, therefore, the CD4 count is used as an indicator to help physicians decide when to begin treatment in HIV-infected patients.

20. Opportunistic Infections
CD4 Count Diseases
/μL Pneumonia (usually caused by bacteria)
Tuberculosis in the lungs
Oral or vaginal yeast infections
Shingles (viral skin infection)
Oral hairy leukoplakia
Kaposi’s sarcoma
/μL All of the above plus:
Pneumoniadue to Pneumocystis carinii (PCP)
Chronic diarrhea
50-100/ μL All of the above plus:
Encephalitis (usually due to toxoplasmosis)
Esophagitis due to yeast or viruses
Meningitis (usually due to cryptococcus)

21. Opportunistic Infections
CD4 Count Diseases
(50-100/µL Tuberculosis outside the lungs
Continued) Chronic herpes simples virus (HSV infection)
Primary brain lymphoma
<50 /µL All of the above, plus:
Widespread infection due to Mycobacterium avium complex
Retinitis, diarrhea, encephalitis due to cytomegalovirus

22. Epidemiology
The virus was first successfully identified and classified in 1981.
The appearance of rare diseases amongst HIV infected persons first alerted scientists to the then unknown virus.
At end of 2003 in the U.S. 1,039, ,185,000 persons infected with HIV/AIDS
Global (2006 statistics): 39.5 million infected with HIV/AIDS
4.3 million new infections in 2006; 2.8 million (65%) of these were in sub-Saharan Africa
Increases in Eastern Europe and Central Asia, where there may have been a more than 50% rise in infection rates since 2004
In 2006, 2.9 million deaths due to AIDS-related illnesses

23. 2003

24. HIV and Disease Early Symptoms:
Human Immunodeficiency Virus (HIV) has an incubation period of about 10 years and eventually leads to Acquired Immunodeficiency Syndrome (AIDS), resulting in the impairment of the immune system.
This can lead to death from infections, secondary diseases from opportunistic bacteria and/or viruses that are usually harmless to people, or many different types of cancers.
Common diseases associated with HIV infection:
Kaposi's sarcoma (KS)
Pneumocystis carinii pneumonia (PCP)
Mycobacterium avium complex (MAC)
Early Symptoms:
Most don’t exhibit symptoms when first infected
However, may have flu-like symptoms (fever, headache, tired, enlarged lymph nodes) 1-2 months after exposure
Very infectious during this period

25. HIV and Disease Later Symptoms:
More sever symptoms may not appear until after 10yrs, however this varies with each individual
Decline in number of CD4 + T cells
The most advanced stage of AIDS is classified as having < 200 CD4+ T cells/cubic millimeter of blood (in healthy adults CD4+ T-cell counts = 1,000+)
Onset of AIDS is characterized by:
weight loss,
fevers/sweats,
fatigue
rashes/flaky skin,
persistent yeast infections,
Pelvic inflammatory disease in women will not respond to treatments,
short-term memory loss,
frequent and severe herpes infections,
shingles
coma
deaths

27. Precautions Post-Exposure Pre-Exposure
Antiretroviral medications (Tenofovir disoproxil fumarate and emtricitabine) administered to HIV-infected women during labor and delivery has shown
~50% reduction in the risk of mother-to-child transmission
Antiretroviral regimens have been shown to be associated with an 80% reduction in risk of HIV infection among healthcare personnel following needle sticks and other accidental exposures, when treatment is initiated promptly
Post-Exposure
In post-exposure cases, the Center for Disease Control and Prevention (CDC) recommends the post exposure prophylaxis (PEP)
Pre-Exposure
Assume any patient’s blood and other bodily fluids are potentially infectious
Protective barriers
Hands and all other skin surfaces must be immediately washed after any contact with blood or body fluids
Extra precaution must be taken in the handling and proper disposal of any sharp instruments used on a patient

28. Treatments
Reverse Transcriptase (RT) Inhibitors – interrupt early stage of viral replication to slow spread of HIV in body and delay start of opportunistic infections
Nucleoside/nucleotide RT inhibitors
Insert faulty DNA building blocks into HIV genome
Prevents completion of DNA chain → no replication
Non-nucleoside RT inhibitors
Bind to reverse transcriptase and prevents reverse transcription
May slow the spread of HIV in the body and delay the start of opportunistic infections.
Zidovudine
Zalcitabine
Trizivir
Stavudine
Lamivudine
Didanosine
Combivir
Abacavir
Delavirdine
Efavirenz
Nevirapine

29. Treatments
Protease Inhibitors – interrupt late stage of viral replication in the HIV life cycle
Side Effects: nausea, diarrhea, gastrointestinal symptoms, serious effects from interaction with other drugs
Fusion Inhibitors – new class of drugs
Fuzeon (enfuvirtide or T-20) interferes with HIV-1’s ability to enter the cell by blocking fusion of the virus to the host cell membrane
HIV cannot enter and infect immune cells
Designed to be used in combination with other anti-HIV treatments
reduces the level of HIV infection in blood
may be effective against HIV resistant to current antiviral treatments
Side Effects: pneumonia, trouble breathing, low bp, chills/fever, skin rash, blood in urine, vomiting
Amprenavir
Indinavir
Kaletra
Nelfinavir
Ritonavir
Saquinavir
Fortovase

30. Treatments
HAART
Treatment has significantly reduced number of deaths from AIDS in the U.S.
Reduces the amount of virus circulating in blood to nearly undetectable levels, although HIV is still present by hiding places such as the brain, lymph nodes, testes, & retina of the eye
Side Effects: severe; decrease in RBCs or WBCs, inflammation of pancreas, painful nerve damage, even death in some cases

31. Vaccines Two types in development:
Currently, no vaccines approved for use by the FDA
Two types in development:
Therapeutic Vaccine - intended to boost the immune systems of those already infected
Preventive Vaccine – intended to generate
an immune response in an uninfected
person to prevent future infection

32. Possible Targets of a Theoretical HIV Vaccine:
gp120, gp160 and gp41 viral surface proteins
to prevent it from binding to the host cell receptor CD4.
Cyclophilin A
At the cell surface – to block from binding to the heparin sulfate receptors
Within the cytoplasm – to keep from expanding the viral core.
Without expansion of the viral core, reverse transcription cannot occur.
Reverse transcriptase
Unable to synthesize new copies of the viral genome.
CCR5 (chemokine) receptor
Cleavage – to inactivate the receptor.
Approximately 13% of people of northern European descent have a naturally occurring deletion of 32 base pairs in the CCR5 gene results.
This mutant CCR5 receptor never reaches the surface of their cells.
Homozygotes for this mutation (1-2% Caucasians) have a resistance to HIV infection.

33. Preventive HIV Vaccines Under Development:
Subunit vaccines – "component" or "protein" vaccines that contain an individual viral components rather than the whole virus
The subunits are made through genetic engineering and administered to induce an anti-HIV immune response
The weak response however may not prevent future infections
Recombinant vector vaccines – use of non-HIV viruses that do not cause disease in humans or have been rendered unable to cause disease (attenuated)
viruses are used as vectors carry copies of HIV genes into human cells, in which HIV proteins will be produced
HIV proteins can stimulate an anti-HIV immune response. The response may be stronger since the recombinant vector vaccines delivers several HIV genes
Vectors being studied for use in HIV vaccines are ALVAC (canarypox virus), MVA (type of cowpox virus), VEE (normally a horse virus), and adenovirus-5 (human virus; usually doesn’t cause serious disease)

34. Preventive HIV Vaccines Under Development:
DNA vaccines – introduce HIV genes into the body, but don’t rely on a virus vector
“Naked" DNA containing HIV genes injected directly into body so that the cells will take it up and produce HIV proteins
HIV proteins will induce immune response against HIV
Prime-Boost Vaccination Strategy
Use one type of vaccine, then administer a second type later to stimulate different parts of the immune system to boost up the overall defense of the body

35. Who Can Benefit from HIV Vaccines?
Healthcare professionals
Blood/organ recipients (especially in underdeveloped countries)
Countries where a significant number of the population has people infected with HIV and has poor health care
Individuals in high risk groups

36. References
Dimmock, N.J., Easton, A.J., and K.N. Leppard. Introduction to Modern Virology, 6th Edition. Blackwell publishing Ltd
Gao, F., Bailes, E., Robertson, D. L., Chen, Y., Rodenburg, C. M., Michael, S. F., Cummins, L. B., Arthur, L. O., Peeters, M., Shaw, G. M., Sharp, P. M., and Hahn, B. H. (1999). "Origin of HIV-1 in the Chimpanzee Pan troglodytes troglodytes". Nature 397 (6718): doi: / PMID
Keele, B. F., van Heuverswyn, F., Li, Y. Y., Bailes, E., Takehisa, J., Santiago, M. L., Bibollet-Ruche, F., Chen, Y., Wain, L. V., Liegois, F., Loul, S., Mpoudi Ngole, E., Bienvenue, Y., Delaporte, E., Brookfield, J. F. Y., Sharp, P. M., Shaw, G. M., Peeters, M., and Hahn, B. H. (2006). "Chimpanzee Reservoirs of Pandemic and Nonpandemic HIV-1". Science Online doi: /science
McQueen, Nancy. Microbiology 401 lectures material. California State University, Los Angeles. 2007
MedLinePlus. "HIV ELISA/western blot." U.S. National Library of Medicine. Last accessed April 16,
Reeves, J. D. and Doms, R. W (2002). "Human Immunodeficiency Virus Type 2". J. Gen. Virol. 83 (Pt 6): PMID
Thomson, M. M., Perez-Alvarez, L. and Najera, R. (2002). "Molecular epidemiology of HIV-1 genetic forms and its significance for vaccine development and therapy". Lancet Infect. Dis. 2 (8): PMID

37. Picture references
Dimmock, N.J., Easton, A.J., and K.N. Leppard. Introduction to Modern Virology, 6th Edition. Blackwell publishing Ltd

38. Questions?