Chapter 28 HIV
HIV disease
(3 terms of HIV/AIDS) indicates infection is causing signs/symptoms
HIV infection
(3 terms of HIV/AIDS) indicates virus has entered body and is replicating, regardless of signs or symptoms
AIDS
(3 terms of HIV/AIDS) last stage of HIV disease, defined by CD4 lymphocyte levels and presence of specific opportunistic infections
pol (polymerase)
(gene code) occasionally translated as single unit with gag, yields additional three enzymes; PR, RT, IN
gag (group antigen)
(gene code) transcribed, translated, then cleaved by viral protease into MA, CA, NC and p6
env (envelope)
(gene code) translated to produce precursor gp160 which is then cleaved by host protease into SU and TM
nucleocapsid
(part of protein) attaches viral RNA to capsid
core
(part of protein) carries 3 important viral enzymes (RT, PR, IN)
capsid
(part of protein) most abundant protein in virus, can be measured in serum to detect early HIV infection
matrix
(part of protein) provides structural support during assembly
Nucleocapsid protein (NC; p7)
(protein) Attaches viral RNA to capsid
Surface glycoprotein (SU or gp120)
(protein) Caplike portion of Env spikes, with which virus attaches to host receptors
Protease (PR)
(protein) Enzyme involved in viral protein processing
Integrase (IN)
(protein) Enzyme that inserts viral cDNA into host genome
Reverse Transcriptase (RT)
(protein) Enzyme that makes copy of viral RNA into DNA
Core Protein (p6)
(protein) Involved in budding of HIV from host cell
Transmembrane protein (TM or gp41)
(protein) Starlike portion of Env spikes, anchoring Env to the viral envelope
HIV disease
-Almost everyone infected with HIV gets this -slowly ends in AIDS unless individual is successfully treated with medications
reverse transcriptase
frequently makes mistakes, lacks proofreading ability
Coat protein
function of capsid protein (CA or p24)
Stabilize virion
function of matrix protein (MA or p17)
P. jiroveci
fungus that infects many, but such low virulence that seldom causes diseases in healthy people
3
how many genes code for structural components
0.3% 30%
percent chance of healthcare providers getting HIV from prick of needle from HIV positive person? Percentage from hepatitis B positive person
55%
percentage of genetic difference between HIV-1 and HIV-2
50%
percentage of untreated patients that progress to AIDS within 9-10 years
sex without condom
primary cause of HIV spread
co-receptor
required for attachment and entry, usually chemokine receptors
anal sex
risk for transmission greater in anal or vaginal sex?
receiver
risk greater for giver or receiver in sexual contact?
6 days to 6 weeks
symptoms of HIV disease appear how long after infection
intigrated or unintigrated
two fates of provirus
HIV genome
typically only 9 genes, but multiple overlapping transcription options
HIV-2
very similar to HIV-1 but transmission is less effective and disease progression is slower
acquired immunodeficiency syndrome
what AIDS stands for
Human immunodeficiency virus
what HIV stands for
Non-M and non-O
what N group of HIV-1 variants stand for (2 things)
Outlier
what O group of HIV-1 variants stand for
Pending Identification of further human cases
what P group of HIV-1 variants stand for
M group
which group of HIV-1 variants is responsible for the current pandemic
generalized rash and central nervous system symptoms
2 less common symptoms of HIV disease
semen; cervical, vaginal secretions
3 places HIV is present (for sexual contact)
Viral, Protozoan, and Fungal infections
3 types of Infections that individuals contract that characterize AIDS
-sexual contact -blood and blood products -vertically (mother to fetus or infant)
3 ways HIV can be transmitted
Placenta, Childbirth, Breastfeeding
3 ways for vertical transmission of HIV
Vertical Transmission
3rd most important route, from mother to fetus or baby
fever, headache, sore throat, muscle aches, enlarged lymph nodes
5 main symptoms of HIV disease
fatal
AIDS is ____ without treatment
HIV
AIDS is caused by
tiny lesions
HIV enters mucosa via ______ during sex
macrophages, resting T cells
Infected ___, ______ typically survive
ELISA
blood products today tested by _____ for antibodies to HIV-1 and HIV-2 and for p24 (capsid protein) or HIV RNA
HIV-1
causative agent of HIV in US and most of the world
HIV-2
causative agent of HIV that is predominant in parts of West Africa and India but has also appeared in US and other countries
breastfeeding
contributes to 15-20% of infant infections of HIV
virions
developing _____ bud from host cell, gain envelope
200
disease is considered AIDS when helper T cell count falls below ___ cells per microliter
Pneumocystis pneumonia
disease previously healthy, homosexual men were getting in 1981
Lymph-adenopathy syndrome
disease that some might have with HIV disease, affects lymph nodes
clinical latency
during this stage, concentration of virions in the bloodstream is relatively stable
Acute Retroviral Syndrome (ARS)
early stage of HIV disease, coincides with high levels of virus replication
AIDS
end stage of a complex disease with many signs
TM (transmembrane) and SU (surface) subunits
enveloped proteins project from envelope and are made from two things
HIV Structure
enveloped virus, two copies of single stranded RNA surrounded by protein capsid
drops
As viral load ______(rises/drops) T cells are replenished
rises
During ARS, viral load _____ (rises/falls)
lentivirus
HIV is in what subgroup of retrovirus family
Retrovirus
HIV is what type of virus
Reverse Transcription and Genome Integration
HIV- encoded reverse transcriptase makes DNA copy of RNA genome
cross-species non-human primates
HIV-1 and HIV-2 thought to have risen by distinct______ transmission events from different ________
genomes
HIV-1 variants classified into subgroups based on...
seroconversion
Initially, HIV-specific antibodies are not detectable, antibodies are developed in the process of...
A, B, C, D, F, G, H, J, K, and CRFs (circulating recombinant forms)
M group is subdivided into these 10 related clades
permanent
Once inserted, the provirus is _____part of cell's genome
Replication and its Consequences
Once integrated, the HIV DNA can be transcribed, translated
Clinical Latency
Period after ARS where virus levels drop and patient become asymptomatic, typically lasts years
End of Clinical Latency
Person becomes increasingly immunodeficient due to declining CD4 lymphocyte count
abbreviation of function or location; size
Proteins make up structure, named by 2 things
double-stranded
RNA template is degraded, cDNA strand is made, yielding ________DNA copy of viral RNA
CD4+ cells
SU portion of Env attaches to (helper t cells, monocytes)
helper T cells
Signs, symptoms of HIV disease and AIDS occur as number of ______ declines
Hybrids (with properties of both)
Simultaneous infection by 2 different clades can yield...
1/3
Without treatment, how many newborns contract HIV
4-6 weeks
Symptoms of ARS typically subside within...
host cell membrane
Viral envelope originates from...
1981
Year AIDS was first discovered
1985
Year HIV screening test was introduced
lower
______(lower/higher) the set point, the longer the patient has
increase
increase or decrease risk with multiple partners, lesions and STDs?
helper T cells
infected ______ typically die
integrase
inserts in linear form into host chromosome
AIDS
leading cause of death among ages 25-44 in 1994
HIV (viral) set point
measured as HIV RNA in plasma, important predictor of disease progression
M (major) group
most HIV-1 variants belong to what group
AIDS-related complex
most people suffer fever, diarrhea, weight loss and fatigue
1%
newborn transmission drops to __% if mother receives antiretrovirals, does not breastfeed and delivers by C section
1000
normal helper T cell count ____ cells per microliter
viral load
number of HIV particles in blood, changes during course of HIV disease
HIV-2
other causative agent, structurally similar to HIV-1
chemokine receptors
people who do not make normal amounts of this are less susceptible to HIV infection