HIV - Dr. S. Sivasankara Narayani

1. 17CY312 – MEDICAL
MICROBIOLOGY (UNIT –II)
Dr. S. SIVASANKARA NARAYANI
ASSISTANT PROFESSOR
DEPARTMENT OF MICROBIOLOGY
AYYA NADAR JANAKI AMMAL COLLEGE
SIVAKASI
06-08-2020Dr.SS
Human Immunodeficiency Virus (HIV)

2. HIV
• Human Immunodeficiency virus
• Causative agent of Acquired immunodeficiency syndrome (AIDS)
• Family Retroviridae
• Two types – HIV type 1 and HIV type 2
06-08-2020Dr.SS

3. HIV
• 1981 – first indication – New York and Los Angeles – Kaposi’s sarcoma and
Pneumocystis carinii – lost immune competence – called – AIDS
• 1983 – Luc Montagnier and colleagues from the Pasteur Institute – isolate
retrovirus – LAV (Lymphoadenopathy associated Virus)
• 1984 – Robert Gallo and colleagues, NIH, USA – Human T - cell lymphotrophic
virus –III or HTLV –III
• 1986 – International committee on virus nomenclature – Human
Immunodeficiency virus (HIV)
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4. STRUCTURE
• Spherical
• Enveloped virus (90 -120nm in size)
• Outer icosahedral shell
• Inner cone – shaped core
• ribonucleoproteins
• Two Single stranded RNA
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5. GENES
Structural
gag–nucleocapsidcoreproteins
pol–RNAdependentDNAPolymerase
env–envelopeglycoproteins
Nonstructuralandregulatorygenes
tat–transactivatinggene
nef -negativefactorgene
rev–regulator ofviralgenes
vif–viralinfectivity factor
Vpu –enhancingmaturation andrelease of progeny
virus (HIV-1)
Vpx – HIV-2
Vpr –stimulating promotor region ofvirus
LTR –Long terminal repeat
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6. ANTIGENS
• Envelopeantigens
Spikeantigens–gp120
Transmembranepellicleprotein–gp41
• Shellantigens
Nucleocapsidprotein–p18
• Coreantigens
Principalcoreantigens–p24
Othercoreantigens–p15,p55
• Polymeraseantigens
p31,p51,p66
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7. LIFECYCLE
• Attachment
• Fusion
• Uncoating
• Reverse Transcription
• Translocation
• Integration
• Replication
• Assembly
• budding
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8. IMMUNOLOGICAL ABNORMALITIES IN HIV
• Lymphopenia
• Selective T cell deficiency –
Reduction in number of T4 (CD4)
cells, inversion of T4 : T8 ratio.
• Decreased delayed hypersensitivity
• Hypergammaglobulinemia – IgG, IgA
• IgM – children
• Polyclonal activation of B cells
• Decreased in vitro lymphocyte
proliferative response to mitogens and
antigens
• Decreased cytotoxic response by T cells
and NK cells
• Decreased antibody response to new
antigens
• Altered monocyte/macrophage functions
• Elevated levels of immune complexes in
serum
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9. 06-08-2020Dr.SS
EVOLUTION OF HIV INFECTION

10. 1
2
3
Gastrointestinal system
– herpetic stomatitis, gingivitis, hairy leukoplakia or Kaposi’s sarcoma.
Intestinal pathogen –cryptosporidium, salmonellae, mycobacteria, isospora, CMV
or adenoviruses
Central nervous system
Toxoplasmosis, cryptococcosis
CMV, herpes simplex, papovaviruses, mycobacteria, aspergillus, candida
Dry cough,dyspnea and fever
Pneumonia – viral (CMV) or fungal (cryptococcus, histoplasma),
Mycobacterium tuberculosis
AIDS

11. 1
2
A
Cutaneous
Kaposi’s sarcoma, herpes lesions, Candidiasis, Xeroderma, seborrheic dermatitis,
prurigo, folliculitis, impetigo and molluscum contagiosum
Irreversible breakdown of immune defence mechanism, leads to progressive
opportunistic infections and malignancies
Malignancies
Kaposi’s sarcoma
AIDS

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LABORATORY DIAGNOSIS

13. TYPES OF EXPOSURE
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14. PROPHYLAXIS
• Modified whole virus
• Subunits, based on envelope glycoproteins expressed in animal cells, bacteria,
viruses – or as synthetic epitopes on adjuvant carriers
• Target cell protection by anti –CD 4 antibody or genetically engineered CD4
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15. TREATMENT
• Nucleoside analogues – Zidovudine (Azidothymidine, AZT), Didanosine,
Zalcitabine, Lamivudine
• Protease inhibitors – Saquinavir, Ritonavir, Indinavir
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16. REFERENCE
• Textbook of Microbiology – Ananthanarayan and Paniker’s – 8th Edition,
2009
06-08-2020Dr.SS
sivasan91@gmail.com

17. QUESTIONS TO THINK
• Why this virus was named as HIV ie. Human Immunodeficiency Virus?
• Is Immunorestorative therapy helpful in the treatment of AIDS patient?
• On what basis differentiate HIV 1 from HIV 2?
• mechanism of HIV genes in the activation of antigens? (any one gene)
• Which method of ELISA is commonly used to diagnose the HIV ?
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18. 06-08-2020Dr.SS