Retroviruses Flashcards
Physical structure of virus
Enveloped and large
Nucleic acid of virus
positive; RNA; diploid
Special requirement of retrovirus RNA and enzyme needed
Must be converted into DNA by reverse transcriptase and integrated within host DNA
3 genera that infect humans
- Lentiviruses
- Oncoviruses - HTLV
- Spumavirus
Lentivirus complications and symptoms
- associated with neurologic and immunosuppressive diseases
- cause persistent infections
Transmission of lentivirus
body fluids
Cell types infected by lentiviruses
CD4 + T cells
Brief history of HIV/AIDs
- gay related immune deficiency
- acquired immune deficiency syndrome
- believed to be native to monkeys of western Africa
3 enzymes that reside in core
- transcriptase
- integrase
- protease
Regions of virus that contain GAG
- capsid and matrix
- group specific antigen
Two glycoproteins that reside on surface
gp120; gp41
Function of gp120
provides attachment points to the tcells
Function of gp41
acts as a fusion protein
Process of HIV entering into the cell
- gp120 binding with CD4
- Conformational change
- CCR5 or CXCR4 recruitment
- gp41 membrane insertion
- membrane fusion
Process of RNA entering nucleus
- reverse transcriptase make viral DNA
- inserted into host cell DNA via integrase
- viral RNA made by host cell polyermase
Process of making new HIV
- viral RNA made by host cell polyermase
- viral RNA serves as template for new RNA and as mRNA
- mRNA make proteins
- new virus made and bud from plasma membrane.
4 stages of HIV infection
Primary; Asymptomatic; Symptomatic; AIDS
Symptoms and duration of primary stage
- short flu like illness
- fever, fatigue, rash, headache, swollen lymph nodes, sore throat
- occurs 1-6 weeks after infection
- no symptoms possible
Description of asymptomatic stage
- average of 10 year duration
- free of symptoms
- swollen glands potentially
- HIV in blood drops
- HIV antibodies detectable
Description of symptomatic stage
- mild symptoms
- immune system deteriorates
- emergence of opportunistic infections and cancers
Description of AIDS stage
- weakened immune system
- aids diagnoses
Bacterial infections associated with AIDS
Tuberculosis; Strep pneumonia
Viral infections associated with AIDS
Kaposi sarcoma; Herpes; Influenza
Fungal infections associated with AIDS
Candida; Pneumocystis carinii; Cryptococcus
Natural progression of opportunistic infections
Bacterial ; Herpes ; Candida ; PCP; CMV, MAC, Fungi
AIDS definition
- CD4 count less than 200cells/m3
- CD4 percent below 14%
- PCP, toxoplasmosis, MAC, Karposi sarcoma
Pathogenesis of AIDS
- profound immunosuppression of AIDS is due to depletion of T4 helper lymphocytes
- followed by high level of HIV in blood
- followed by low level, but incubation; massive turnover of CD4 cells
- immune system succumbs; AIDS develop when CD4 not replaced
Control of HIV/AIDS
- block transmission
- nucleoside RT inhibitors
- nonnucleoside RT inhibitors
- protease inhibitors
