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32 Cards in this Set
- Front
- Back
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HIV-1 Virion:
Human immunodeficiency virus ... -Surrounds cone-shaped capsid Genome is composed of identical copies of ...-stranded, ... RNA Two types of HIV: 1 and 2 |
Envelope
single positive |
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HIV-1 virion:
the genome contains genes that encode for gag, pol, env proteins in addition to non-structural proteins -... encodes for capsid, matrix and nucleic acid binding proteins -... encodes for polymerase with reverse transcriptase activity, protease and integrase -... encodes for the envelope glycoproteins |
gag
pol env |
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HIV-1:
leads to an induced ... known as acquired immunodeficiency syndrome (AIDS) -significant reduction in the number of ... cells highly ... infection |
immunosuppression
CD4+ T cytolytic |
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Overview of the HIV-1 replicative cycle:
HIV-1 binds to the ... found on CD4 T cells, macrophage and other cells -additionally binds to a chemokine receptor CCR5 or CXCR-4 binding to the chemokine receptor allows for fusion of the viral particle to the ... -the genome is released into the ... once in the cytoplasm, the early phase of replication occurs producing a viral double-stranded DNA called the ... -the ... synthesizes a complementary DNA strand called a cDNA -the (+) RNA strand is degraded and a (+) strand of DNA is synthesized the provirus is then integrated in to host’s genome the provirus provides the source for the production of the viral genome, (...) RNA, and mRNAs that encode for the viral proteins assembly of the genome and the viral proteins occurs in the ... the envelope displaying the envelope proteins is derived from the cell membrane as the particle ... from the cell |
CD4 receptor
cell membrane cytoplasm provirus reverse transcriptase + cytoplasm buds |
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HIV-1 Viral Spread:
-virus has ... infectivity -establishes ... in CD4+ T cells |
high
latency |
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HIV-1 Transmission:
primarily passed through ... contact -oral, vaginal and anal intercourse inoculation with contaminated blood -transfusion of blood and blood products -needle sharing -epithelium and mucus membrane exposure in healthcare workers maternal-fetal transmission -intrauterine transmission -peripartum transmission -breast milk |
sexual
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HIV-1 Spread within host:
primarily infect ... cells -infection of CD4+ cells by ... particles -proliferation of infected cell harboring integrated ... -fusion of infected and uninfected cells (... formation) ... cells bind to and transport HIV virus to the CD4+ T cells in the lymph nodes Infection of CD4+ T cells causes ... infection |
CD4+ T
virus provirus syncytia dendritic sytemic |
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Evasion of Host Defenses by the HIV-1:
Dysregulation and destruction of T lymphocytes and macrophages -inactivates, damages or destroys the immune cells required to activate cell-mediated killing and production of ... antibodies *chronic infection that produces huge amounts of virus *large numbers of ... cells are continuously killed and replaced Antigenic drift -high mutation rate in ..., the viral attachment protein -HIV-1 remains one step ahead of the CTLs and neutralizing antibodies directed against it High glycosylation of the gp120 - ... antibodies cannot detect the gp120 Establishment of ... in infected CD4+ cells |
neutralizing
CD4+ T gp120 neutralizing latency |
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HIV-1 Viral Pathogenesis:
-course of HIV parallels the ... in CD4 T-cell numbers and the amount of virus in the blood |
reduction
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Acute phase (HIV-1):
marked by a dramatic increase in ... load and drop in helper T cells numbers the viral load shows marked ... as virus-specific antibodies and CTLs are generated accompanied by flu-like symptoms caused by ... and other cytokines generated by the immune response -... due to large numbers of CD4+ T cells found in the lymph nodes |
viral
decrease interferon lymphadenopathy |
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Chronic phase (HIV-1):
viral load less than at the height of acute infection, but viral replication continues in the ... -virus is continually being produced and cleared by antibodies -... cells are being replenished daily providing new host cells for viral infection -infected CD4+ T cells produce more virus and are consequently destroyed by the immune response or the virus -the cycle begins again when these T cells are replaced |
lymph nodes
CD4+ T |
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Systemic immune deficiency due to HIV-1 (Immunosuppression):
CD4+ T-cell counts fall below 200/mL coupled with an increase in viral load -loss of ... specific immune responses appearance of ... infections |
antigen
opportunistic |
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Clinical latency of HIV-1:
-... period |
asymptomatic
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HSV Virion:
Herpes simplex virus (envelope or no envelope?) Genome is a linear, ...-stranded DNA -Genome is contained within an icosahedral ... surrounded by tegument |
Envelope
double capsid |
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Herpes simplex virus type 1 and 2:
infectious agents with ... host cell range, multiply efficiently and rapidly destruction of the infected cause a myriad of clinical presentations -age -immune status -site of infection -type of virus most recognizable symptom is the clustering of ... at the site of infection many infected individuals are ... |
wide
blisters asymptomatic |
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HSV Replicative Cycle:
Transcription, replication and assembly take place in the ... ... early genes expressed first -Activate the ... early genes ... early genes involved in viral DNA replication ... genes are transcribed after viral DNA replication is completed -Involved in the assembly of the progeny viral particles |
nucleus
Immediate delayed Delayed Late |
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HSV Replicative Cycle:
-virus attaches to the cell surface receptors; ... of envelope to the plasma membrane -the tegument-capsid structure transported to the nuclear pores where DNA is released into the ... -transcription, replication and assembly take place in the ... |
fusion
nucleus nucleus |
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Characteristics of a herpes simplex infection:
1. Ability to reproduce in cells that are not ... 2. Rapid production of ... of new virus 3. Establishment of a ... infection in the central nervous system |
growing
burst latent |
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HSV Viral Spread:
... predominantly infects the areas surrounding the lips and mouth (oral herpes) -60% of population infected -40% of new cases of oral herpes caused by ... ... predominantly infects the genital areas -25% of population infected -40% of new cases of genital herpes caused by ... any region of the skin or mucous membranes can be infected |
HSV-1
HSV-2 HSV-2 HSV-1 |
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Person-to-person transmission of HSV:
spreads when the virus that is produced in the epithelium of an infected individual comes into contact with the epithelial cells of an ... individual -skin-to-skin contact -saliva and genital secretions containing the virus contacts abraded skin or in the genital or oral mucosa |
uninfected
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Spread within host of HSV:
usually very ... virus establishes infection at the site of contact neurons surrounding the site of infection can also contract the virus -not ... in nerve cells -establish ... in the associated sensory ganglia -the viral genome does not ... into the host genome |
localized
cytolytic latency integrate |
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Evasion of Host defenses by HSV:
Establishment of ... infection in neurons -HSV do not ... efficiently in neurons -Few HSV encoded proteins produced by infected neurons -Rarely destroyed by CTLs -Latency associated transcript interferes with apoptosis Interferes with the action of complement proteins and antibodies -Proteins found on the surface of the HSV bind the ... region of IgG antibodies -Interferes with ... by complement proteins and IgG antibodies |
latent
replicate Fc opsonization |
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HSV Viral Pathogenesis:
rapid replication in ... cells -destruction of infected epithelial cells -production of a large viral ... ulceration of the infected epithelium; ... infection -formation of ulcerations or blisters when cells die as a result of the virus or the immune response -cell-mediated immunity known to contribute to symptoms infection of nerve cells that surround infected areas -establishes a latent infection in sensory ganglia; ... infection -upon reactivation, infection of more epithelial cells in the general area of the primary infection *usually preceded by ... symptoms -subsequent infections are controlled mainly by cell-mediated responses; lesser severity and shorter duration It should be noted that virus is almost constantly shed by symptomatic and asymptomatic individuals. |
epithelial
burst cytolytic non-cytolytic prodromal |
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HPV Virion
Human papillomavirus Capsid -Highly resistant to environmental factors ...-stranded ... DNA Around 100 different types of HPV identified |
Double
circular |
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HPV:
-infects the ... and ... membranes -different types of HPV cause different clinical presentations Clinical presentation: development of ... at the site of infection -skin and genital ... establishment of subclinical infection that result in precancerous lesions -individuals tend to be ... -subset of sexually transmitted HPVs that can lead to precancerous lesions |
skin and mucus
warts warts asymptomatic |
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Important Aspects of HPV Replicative Cycle:
-HPV targets ... cells located beneath the skin and mucosal surfaces -Viral replication is synchronized with the maturation of the ... epithelial cells |
basal
basal |
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Important Aspects of HPV Replicative Cycle:
-hitching a ride from basal epithelial cells maturing through the layers of the skin, HPV is released with the ... cells that are shed |
dead
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Replication of HPV:
controlled by the ... cell’s transcriptional machinery as determined by the differentiation of skin and mucosal epithelium access to the basal cell layer is by ... in the skin or mucosa the early genes stimulate cell division which facilitates viral genome replication by the host cell’s DNA polymerase as the basal cells differentiate, transcription factors expressed in different layers of the skin/mucosa promote the transcription of different viral genes late genes that encode for the structural proteins are expressed only in the terminally differentiated ... surface -assembly of ... within the nucleus viral particles shed with the dead cells of the skin/mucosa |
host
breaks upper capsid |
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HPV Viral Spread:
Direct contact with an ... individual -Normally spread by sexual contact -Oral transmission leads to respiratory infection -Maternal-fetal transmission Direct contact with ... on which the virus has been deposited -Mode for transmission of skin warts -Not proven to be a source of anogenital transmission |
infected
fomites |
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Evasion of Host Defenses by the HPV:
Maintenance of a proliferative state -mature epithelial cells that are migrating to the surface of the skin normally shut down proliferation -viral infection triggers unscheduled cellular DNA ... *HPV protein E7 binds to pRB releasing block of cell cycle progression *abnormal cellular replication incites ... *HPV protein ... inhibits cellular apoptosis by binding p53 No interferon production or cell death -mRNA only transcribed from one strand of the DNA -establishes a ... infection Hides in basal epithelial cells -follows the basal epithelial cells through skin ... without exposure |
replication
apoptosis E6 non-cytolytic maturation |
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HPV Viral Pathogenesis:
HPV infects and replicates in the ... epithelium of skin and mucus membranes -induces epithelial proliferation warts develop as a result of ... stimulation of cell growth and a thickening of the basal and prickle cell layers -cell cycle dysregulation -appear several months after initial infection viral infection usually remains ... and will resolve spontaneously -resolution possibly the result of immune response, in particular ... |
squamous
viral localized CTLs |
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Oncogenic potential of HPV:
HPV-... and HPV-... known to cause cervical papillomas and dysplasia ->dozen HPVs are classified as oncogenic ->90% of cervical cancer contain ... HPV DNA integration of the viral genome in the host’s genome -high expression of the E6 and E7 genes -E6 and E7 genes are considered ... as they inactivate the tumor suppressor proteins p53 and pRB respectively |
16
18 integrated oncogenes |
