HUMAN PAPILLOMA VIRUS (HPV)

HUMAN PAPILLOMA VIRUS
HUMAN PAPILLOMA VIRUS
(HPV)
(HPV)
By:
By:
Nathalia Cruz
Nathalia Cruz

What is a Virus?
What is a Virus?
►
Exceptionally simple living microbes.
Exceptionally simple living microbes.
►
Contain a single type of nucleic acid (DNA or RNA) and a
Contain a single type of nucleic acid (DNA or RNA) and a
protein coat.
protein coat.
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Obligatory intracellular parasites.
Obligatory intracellular parasites.
►
Range from 20 to 14.000 nm in length.
Range from 20 to 14.000 nm in length.

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It’s classification is based on type of nucleic acid, strategy
It’s classification is based on type of nucleic acid, strategy
for replication, and morphology
for replication, and morphology

HUMAN PAPILLOMA VIRUS
HUMAN PAPILLOMA VIRUS
►
HPV is the virus that causes warts.
HPV is the virus that causes warts.
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More than 100 different kinds, 30-some of this cause
More than 100 different kinds, 30-some of this cause
genital HPV.
genital HPV.
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Spread by sexual contact or from mother to baby.
Spread by sexual contact or from mother to baby.
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Genital warts appear 6 weeks to 8 months after contact
Genital warts appear 6 weeks to 8 months after contact
with an HPV infected person.
with an HPV infected person.

HPV
HPV
►
The most common sexually transmitted disease worldwide.
The most common sexually transmitted disease worldwide.

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Certain types of HPV are linked with cervical cancer.
Certain types of HPV are linked with cervical cancer.
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Divided into 2 subcategories: Genital Warts and Cervical
Divided into 2 subcategories: Genital Warts and Cervical
Dysplasia.
Dysplasia.
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Most people do not know they have it.
Most people do not know they have it.
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There are high risk and low risk types of it.
There are high risk and low risk types of it.

HISTORY
HISTORY
►
The papillomaviruses are part of the PAPOVAVIRIDAE
The papillomaviruses are part of the PAPOVAVIRIDAE
family of DNA tumor viruses.
family of DNA tumor viruses.
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First discovered in the early 40’s.
First discovered in the early 40’s.
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Gained notoriety in the early 80’s when it was discovered
Gained notoriety in the early 80’s when it was discovered
that some types of HPV caused cervical cancer.
that some types of HPV caused cervical cancer.

MORPHOLOGY
MORPHOLOGY
►
Papilloma virus genome is circular covalently closed double
Papilloma virus genome is circular covalently closed double
stranded DNA of about 8 kbp.
stranded DNA of about 8 kbp.
►
All PV genes are coded in one of the 2 DNA strands
All PV genes are coded in one of the 2 DNA strands
utilizing the alternative splicing for the individual
utilizing the alternative splicing for the individual
expression of each gene.
expression of each gene.
►
Papillomavirus expression is characterized by a large array
Papillomavirus expression is characterized by a large array
of mRNAs cells coding for different genes.
of mRNAs cells coding for different genes.
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55 nm in diameter.
55 nm in diameter.

APPEARANCE
APPEARANCE

MECHANISM OF INFECTION
MECHANISM OF INFECTION
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All PV exhibit extreme specificity for infection on epithelial
All PV exhibit extreme specificity for infection on epithelial
cells.
cells.
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The papillomavirus epitheliotrophy resides in the
The papillomavirus epitheliotrophy resides in the
interaction of specific transmission factors with the viral
interaction of specific transmission factors with the viral
regulatory region LCR.
regulatory region LCR.
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The infection normally results in hyperproliferation of the
The infection normally results in hyperproliferation of the
host cell and may lead to transformation and
host cell and may lead to transformation and
immortalization.
immortalization.

GENITAL WARTS
GENITAL WARTS
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Sometimes called condylomata acuminata.
Sometimes called condylomata acuminata.
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Are soft, moist or flesh colored, and appear in the genital
Are soft, moist or flesh colored, and appear in the genital
area within weeks or months after infection.
area within weeks or months after infection.
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Sometimes appear in clusters and are either raised or flat,
Sometimes appear in clusters and are either raised or flat,
small or large.
small or large.
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Women: appear in the vulva, cervix, vagina and anus.
Women: appear in the vulva, cervix, vagina and anus.
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Men: Can appear on the scrotum or penis.
Men: Can appear on the scrotum or penis.

LIFE CYCLE (HPV-16)
LIFE CYCLE (HPV-16)
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Starts with the infection of the host cell.
Starts with the infection of the host cell.
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The virus DNA is released within the nucleus
The virus DNA is released within the nucleus
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Numerous cellular transcription factors interact
Numerous cellular transcription factors interact
with the non-coding viral regulatory region (LCR),
with the non-coding viral regulatory region (LCR),
starting transcription of the two hpv-16
starting transcription of the two hpv-16
transforming early genes (E6 and E7).
transforming early genes (E6 and E7).
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The transforming proteins interact with the cellular

The transforming proteins interact with the cellular
antioncogenic regulator p53 disrupting the cell
antioncogenic regulator p53 disrupting the cell
cycle.
cycle.

LIFE CYCLE
LIFE CYCLE

HPV TYPES
HPV TYPES
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Numbered in order of discovery.
Numbered in order of discovery.
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30 HPV types primarily infect the squamous epithelium of
30 HPV types primarily infect the squamous epithelium of
the lower anogenital tracts of both males and females.
the lower anogenital tracts of both males and females.
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HPV types 6, 11, 42, 43, or 44 present as papillary
HPV types 6, 11, 42, 43, or 44 present as papillary
condylomas, may also present as flat lesions that may or
condylomas, may also present as flat lesions that may or
may not be visible to the unaided eye are part of the “low-
may not be visible to the unaided eye are part of the “low-
risk” HPV types.
risk” HPV types.
►

Types 16, 18, 31, 33, 35, 45, 51, 52, and 56 are
Types 16, 18, 31, 33, 35, 45, 51, 52, and 56 are
considered “high-risk” types because they have been found
considered “high-risk” types because they have been found
in cervical and other lower genital tract cancers.
in cervical and other lower genital tract cancers.



HPV GENOMIC ORGANIZATION
HPV GENOMIC ORGANIZATION
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Three main regions (early,
Three main regions (early,
late and the long control
late and the long control
region)
region)
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(E) resides the
(E) resides the
transformation and
transformation and
immortalization potential.
immortalization potential.
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(L) Two capsid genes.
(L) Two capsid genes.
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(LCR) contains all the cis-
(LCR) contains all the cis-
regulatory elements.
regulatory elements.

HOW HPV CAUSES CANCER
HOW HPV CAUSES CANCER
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HPV DNA integrates into the host genome.
HPV DNA integrates into the host genome.
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The proteins
The proteins
E6
E6
and E7 are produced from the resultant DNA.
and E7 are produced from the resultant DNA.
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E6 binds and degrades p53 (a tumor suppressor gene).
E6 binds and degrades p53 (a tumor suppressor gene).
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If the DNA is altered, the cell keeps replicating. The mutation rate of
If the DNA is altered, the cell keeps replicating. The mutation rate of
the cell increases.
the cell increases.
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E7 binds and degrades retinoblastoma (another tumor suppressor
E7 binds and degrades retinoblastoma (another tumor suppressor
gene).
gene).

►
Retinoblastoma normally keeps the cell from growing too fast or
Retinoblastoma normally keeps the cell from growing too fast or
responding to growth stimulators. This inhibitory factor is now lost.
responding to growth stimulators. This inhibitory factor is now lost.
►
without these two mechanisms to slow down cell growth and prevent
without these two mechanisms to slow down cell growth and prevent
mutation. . .
mutation. . .
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Malignant Transformation Occurs.
Malignant Transformation Occurs.

HPV TREATMENT
HPV TREATMENT
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Genital warts can be treated by
Genital warts can be treated by
a doctor and by different
a doctor and by different
methods.
methods.
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Podofilox gel:
Podofilox gel:
A patient-
A patient-
applied treatment for external
applied treatment for external

genital warts.
genital warts.
►
Imiquimod cream:
Imiquimod cream:
A patient-
A patient-
applied treatment.
applied treatment.
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Chemical treatments (including
Chemical treatments (including
trichloracetic acid and
trichloracetic acid and
podophyllin), which must be
podophyllin), which must be
applied by a trained health care
applied by a trained health care
provider to destroy warts.
provider to destroy warts.
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Cryotherapy:
Cryotherapy:
Uses liquid
Uses liquid
nitrogen to freeze off the warts.
nitrogen to freeze off the warts.
►
Laser therapy:
Laser therapy:

Uses a laser
Uses a laser
beam or intense lights to
beam or intense lights to
destroy the warts.
destroy the warts.
►
Electrosurgery:
Electrosurgery:
Uses and
Uses and
electric current to burn off the
electric current to burn off the
warts.
warts.
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Surgery:
Surgery:
Can cut away the
Can cut away the
wart in one office visit .
wart in one office visit .
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Interferon:
Interferon:
an antiviral drug,
an antiviral drug,
which can be injected directly
which can be injected directly
into warts.

into warts.

CURE
CURE
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There is currently no cure for human papillomavirus.
There is currently no cure for human papillomavirus.
►
Once an individual is infected, he or she carries the virus
Once an individual is infected, he or she carries the virus
for life even if genital warts are removed.
for life even if genital warts are removed.
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The development of a vaccine against HPV is under way,
The development of a vaccine against HPV is under way,
but is still not available.
but is still not available.
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If left untreated, some genital warts may regress on their
If left untreated, some genital warts may regress on their
own.
own.

SOURCES
SOURCES
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iteFiles/LectureList.htm#LectureList
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WWW.STDSERVICES.ON.NET/STD/WARTS
WWW.STDSERVICES.ON.NET/STD/WARTS
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