Immunology Flashcards
What are the 2 viral glycoprotein spikes that bind to the primary CD4 receptor?
Gp120 and gp41
What are the 2 7-transmembrane G-protein coupled receptors?
CCR5 and CXCR4
Which receptors are expressed primarily on T cells, and is called a T-trophic virus when using these receptors?
CD4 and CXCR4
Which receptors are expressed on macrophages, and are called m-trophic when using these receptors?
CD5 and CXCR5
For viral entry, what does the Gp120 do to CD4 and CCR5 ?
Pulls the virus closer to the cell membrane
Later, gp120 binds T0 CD4 and CXC4 receptors, and causes a conformational change to expose which marker?
Gp41
What is the role of Gp41 for viral entry?
Fuses viral and cell membranes –> allows viral RNA to penetrate the cell
What would happen if you are deficient in CCR5 or CXCR4?
You’re immune to HIV
What is released into the cell when the HIV virus is uncoating?
+ ssRNA
RT
Integrase
Protease
What is the role of reverse transcirptase for HIV?
RNA –> DNA
What does the HIV use to integrate into the host cell DNA?
Integrase
Which host enzyme transcribes the viral DNA?
RNA polymerase II
Which cytokine is stimulated for its transcription during extrinsic stimuli, which therefor stimulates gene transcription of the HIV genome, causing the release of viral RNA into the cytoplasm?
IL-2 and its R
What happens to the viral RNA once it’s inside the cytoplasm?
proteins are synthesized from it
What is the enzyme that cuts long protein chains into individuals proteins?
Protease
After sexual transmission, what “tissue” does HIV infect?
MALT
Which cells mediate the initial stages of HIV infection?
M-trophic cells
CD4/CCR5
A mutation in the what gene shifts the tropism of HIV to T-trophic, which allows HIV to infect CD4+ T cells?
Gp120
What reduces the # of Th cells in HIV infections?
Direct HIV-induced cytolysis
Cytotoxic Tc immune cytolysis
Chronic activation in response to the large HIV Ag challenge –> rapid terminal differentiation
Infected T cells are killed by what 4 mechanisms?
Accumulation of nonintegrated circular DNA copies of genoma
Increased permability of plasma membrane
Syncytia formation
Induction of apoptosis
What do activated CD4 Th cells release to initiate immune response, which activates macrophages, other T cells, B cells, and NK cells?
Cytokines
Under what CD4 levels do Ag-specific immune responses not work and humoral response is uncontrolled?
< 200 cells/uL
What 2 factors cause the outgrowth of opportunistic intracellular infections when CD4 levels get < 200?
Lose activating of macrophages Delayed type (IV) hypersensitivity
What are neutralizing antibodies generated against to cause Ab-dependent cellular cytotoxicity response?
Gp120
What happens to CD8 levels in HIV infections? Why?
They ↓ b/c they require activation by CD4
A reduction in CD8 cells cause the possibility of what type of infections in HIV?
viral
Why does the infeciton of lymphocytes and macrophages is a way for HIV to escape immune control?
inactivation of key element of immune defense
What happens to gp120 for HIV to escape immune control?
Antigenic drift and heavy glycosulation
During what time is stage 1, stage 2, and stage 3 of HIV infections?
Stage 1: 0-24mo
Stage 2: 24-65mo
Stage 3: 65 onwards
During stage 1 of the HIV infection, which of the following markers peaks from 0-12 months and then drops to low levels?
Virus
CD4/T-cell count
Anti-HIV-1 Ab
Virus
During stage 1 of the HIV infection, which of the following markers fluctuates with a steady decline?
Virus
CD4/T-cell count
Anti-HIV-1 Ab
CD4/T-cell count
During stage 1 of the HIV infection, which of the following markers slowly increases?
Virus
CD4/T-cell count
Anti-HIV-1 Ab
Anti-HIV-1 Ab
During stage 2 of the HIV infection, which of the following markers slowly increases and then drops off at 60mo?
Virus
CD4/T-cell count
Anti-HIV-1 Ab
Anti-HIV-1 Ab
During stage 2 of the HIV infection, which of the following markers stays low through the entire stage?
Virus
CD4/T-cell count
Anti-HIV-1 Ab
Virus
During stage 2 of the HIV infection, which of the following markers still steadily decreases?
Virus
CD4/T-cell count
Anti-HIV-1 Ab
CD4/T-cell count
During stage 3 of the HIV infection, which of the following markers rises sharply?
Virus
CD4/T-cell count
Anti-HIV-1 Ab
Virus
During stage 3 of the HIV infection, which of the following markers still slowly declines?
Virus
CD4/T-cell count
Anti-HIV-1 Ab
CD4/T-cell count
During stage 3 of the HIV infection, which of the following markers continues to decline and then plateau?
Virus
CD4/T-cell count
Anti-HIV-1 Ab
Anti-HIV-1 Ab
At what CD4 level is full blown AIDS?
< 200 cells/mm3
During which stage do u see ARC?
Stage 2
During which stage do u see AIDS dementia?
Stage 3
During which stages do u see chronic lymphadenopathy?
Stages 1-2
True or False: you start to see disease Sx during the middle phase of stage 2.
FALSE.
you dont see opportunists until stage 3
What is the initial Sx of HIV infections?
Flu-like
Which class of opportunistic diseases does these bugs belong to for HIV pts?
Toxoplasmosis (brain), cryptosporidiosis (GI), isosporiasis (GI)
Protozoal
Which class of opportunistic diseases does these bugs belong to for HIV pts?
Candidiasis, PCP, cryptococcosis, Histoplasmosis, Coccidiodomycosis
Fungal
Which class of opportunistic diseases does these bugs belong to for HIV pts?
CMV, HSV, EBV, HHV-8
viral
Which class of opportunistic diseases does these bugs belong to for HIV pts?
Disseminated Mycobacterium spp, Salmonella speticemia
Bacterial
Which infections do u see in a CD4 count of 500-200?
Oral thrush
Which infections do u see in a CD4 count of 200-100?
PCP, AIDS dementia
Which infections do u see in a CD4 count of <100?
Toxoplasmosis, cryptococcus, cryptosporidiosis
Which infections do u see in a CD4 count of <50?
CMV retinitis, MAI complex, progressive multifocal leukoenceophalopathy, primary CNS lymphoma due to EBV
What is teh test of choice for the montoring of CD4 T cell counts in AIDS pts?
Flow cytometry
What is the gene that reduces cell surface expression of CD4 and MHCI molecules, alters T-cell signalling pathways, regulates the cytotoxicity of the virus, and is required to maintain high viral loads?
Nef gene
True or False: the nef gene appears to be essential for causing the infection to progress to AIDS.
True
This is the form of treatment which is a mixture of drugs with different mechanisms of action that leads to less potential to breed resistnace in HIV pts.
HAART
highly active antiretroviral treatment
This is the class of antiretrovirals that are phosphorylated by cellular enzymes and are incoporated into cDNA by RT to cause DNA chain termination.
Nucleoside Analogue RT inhibitors (NRTI)
This is the class of antiretrovirals that interefere with HIV-1 Gag-Pol polyprotein processing and inhibit the late stage of HIV-1.
NNRT
This is the class of antiretrovirals that block the morphogenesis of the viron by inhibiting the cleavage of proteins and resulting virus is inactive.
Protease inhibitors
This is the class of antiretrovirals that inhbiits binding to the CCR5 co-receptor with a receptor agonist or fusion or viral envelope and cell membrane witha peptide that blocks the action of the gp41 molecule and prevents the intial infection treatment.
Binding and Fusion inhibitors
This is the class of antiretrovirals that inhibits the viral DNA incorporation into the genome.
Integrase inhbitor
This is the leukemia virus that can replicate but cannot transform cells in vitro, and causes cancer after a long latency period of at least 30 years.
HTLV-1
What are the 3 ways u can get HTLV-1?
Blood transfusion
Sex
breastfeeding
Which cells does the HTLV-1 virus replicate?
CD4 and DTH T cells
What is the protein that HTLV-1 makes that transactivates the celllar genes for th T cell growth factor IL-2 and its receptor which activates growth of infected cells?
Tax protein
What is the HTLV-1 protein that limits tax’s activity, promoting cell survival?
HBZ protein
What may happen to the chromosomes in HTLV-1 stimualted cells to cause the transition to leukemia?
Chromosomal abberations and rearrangements in the T cell Ag receptor
Where is HTLV-1 endemic?
Southern Japan (breast milk)
Carribean
Central Africa
African Americans in the SE USA (IV drug use)
Though HTLV-1 infections are typically asymptomatic, what can it progress to in approximately 1/20 people?
ATLL
adult acute T cell lymphocytic leukemia
What are the malignant cells called in ATLL because of pleomorphism and containing lobulated nucleI?
Flower cells
What is the prognosis for ATLL?
Usually fatal within a year
These are antigens that vary between members of the same species.
Alloantigens
This is an immune response that alloantigens provoke.
Alloreaction.
What type of transplants cause Graft-vs-Host (GvH) disease?
Bone marrow
What happens with the grafted bone marrow and the recipient in GvH disease?
Alloreaction from mature T cells in grafted bone marrow that attack and reject the recipients healthy tissue
(the foreign T cells start attacking the recipient)
What are the 4 common affected organs in GvH disease?
Skin
Liver
Lungs
Intestine
What are the skin manifestations of GvH disease?
Bright red rash that involves the palms and soles, starts on the face and neck and moves to the trunk and limbs.
What are the GI manifestations of GvH disease?
profuse watery diarrhea, abnormal liver fxn tests
This is self-tissue transferred from 1 body site to another, and is commonly used in burn pts and plastic surgery where some middle-aged woman wants to look like a duck so she gets her butt fat sucked out and injected into her lips.
Autograft
What is the type of graft between genetically identical twins?
Isograft
Which blood type has both A and B Ab;s in the plasma?
O
What blood type has neither A or B Ab’s int he plasma?
AB
What must be the blood type of a mother to cause anemic babies?
Rh-
What type of hypersensitivity rxn is blood transfusion?
Type II
What type of organ rejection occurs within the first 24 hours?
Hyperacute graft rejection.
What must the most have for the graft to cause hyperacute rejection?
pre-existing Ab’s
What happens to the grafted tissue in hyperacute rejection?
It’s infiltrated with PMNs –> massive blood clots preventing revascularization
How can an individual have pre-exisitng Ab’s for allogenic MHC?
Recipients of repeated blood transfusions
Women who have had repeat pregancies
People who have already had 1 graft
Under what conditon can the mother make Ab’s against any patenral HLA allotype expressed by the baby, since normally fetal and maternal cirulations are segregated?
During the trauma of child birth
So if the mom makes Ab’s against paternal HLA’s, what can happen to future pregnancies? On future organ transplant?
Pregnancies- no effect
Organ transplant- complicate the search for compatible organ transplant
This is the form of graft rejection where within 10 days there is massive infiltration of macrophages and lymphocytes at the site of tissue destruction and activation of Th cells.
Acute graft rejection
What is the test that is used in the event of a donor-recipient that is not a complete mismatch to determin the degree of class II compatibility?
Mixed lymphocyte reaction
In a Mixed lymphocyte reaction, the donor lymphocytes are irradiated and serve as what?
Simulator cells
The simualtor cells from the donor and the reponder lymphocytes from the recipient are mixed together and what happens in a + test?
recipient cells that proliferate indicated a T cell activation, and the greather the MHC difference, the greater the proliferation.
How long after the surgery does a chronic graft rejection take place?
Months-years
What may provote chronic rejection?
viral infection
True or False: use of immunosuppresive drugs has increased short-term survival but nothing can be done to prevent a chronic graft rejection.
True
