This document discusses HPV and the immune response to HPV. It covers HPV infection and pathogenesis, how HPV evades the immune system, and the immune response to HPV. Key points include that HPV infects basal keratinocytes and replicates without causing inflammation, allowing persistent infection. HPV proteins E6, E7, and E5 help HPV evade detection by suppressing interferon signaling and downregulating MHC class I presentation. Despite this, most HPV infections are cleared by cell-mediated immunity within 2 years.
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Cancro do Colo do Útero
Em Portugal
4ª neoplasia na mulher
Neoplasia urogenital
Alta taxas:
Incidência 16 / 100 000
Mortalidade 6 / 100 000
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Cancro do Colo do Útero
Etiologia
1842 – A culpa era da profissão…
1901 – A culpa era da religião…
60s – A culpa era da circuncisão…
70s – A culpa era dos Herpes…
80s – Associação com HPV
odds ratio: 60 (95% C.I. 49-73)
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Cancro do Colo do Útero
Patologia
Desenvolvimento de Lesões Precursoras que podem evoluir para Cancro
Infecção Ca Colo Útero
6 meses 3 anos 6 anos 10 anos
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Cancro do Colo do Útero
Patologia
Colo Útero Normal Normal
Histologia
Citologia
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Cancro do Colo do Útero
Patologia
CIN 1
Histologia
Citologia
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Cancro do Colo do Útero
Patologia
CIN 2
Histologia
Citologia
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Cancro do Colo do Útero
Patologia
CIN 3
Histologia
Citologia
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Cancro do Colo do Útero
Patologia
Carcinoma In Situ
Histologia
Citologia
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Cancro do Colo do Útero
Patologia
Carcinoma Invasor
Histologia
Citologia
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Cancro do Colo do Útero
Patologia
Carcinoma Invasor
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Cancro do Colo do Útero
Susceptibilidade Genética
16. +
Cancro do Colo do Útero
Susceptibilidade Genética
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Vírus do Papiloma Humano (HPV)
Características Gerais
Vírus com distribuição ubíqua
Independentemente do género, idade, etnia ou localização geográfica
Vírus epitelio-mucosotrópico
Infecta células epiteliais e mucosas
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Vírus do Papiloma Humano (HPV)
Características Gerais
Descritos quase 200 tipos de HPV
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Vírus do Papiloma Humano (HPV)
Características Gerais
Família Papillomaviridae
Estrutura icosaédrica ( 55nm)
Vírus de DNA cadeia dupla
Genoma com 8000pb
positivo
2 genes estruturais (L1 e L2)
7 ou 8 genes precoces (E1 a E8)
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Vírus do Papiloma Humano (HPV)
Características Gerais
GENE FUNCTION
E1 DNA-dependent ATPase, ATP dependent helicasE;
Allow unwinding of the viral genome and act as an elongation factor for DNA replication.
E2 Responsible for recognition and binding of origin of replication. Exists in two forms: full length
(transcriptional transactivator) and truncated (transcriptional repressor). The ratio of these found in the
heterotrimeric complex formed before complexing with E1 regulates transcription of viral genome.
E3 ????
E4 Late Expression: C terminal binds intermediate filament, allowing release of virus-like particles. Also
involved in transformation of host cell by deregulation of host cell mitogenic signalling pathway.
E5 Obstruction of growth suppression mechanisms: e.g EGF receptor; activation of mitogenic signalling
pathways via transcription factors: c-Jun and c-Fos (important in ubiquitin pathway degradation of p53
complex by E6). Inactivation of p21 (p53 induced expression halts cell cycle until DNA is proof-read for
mutations).
E6 Transformation of host cell by binding p53 tumour suppressor protein.
E7 Transforming protein, binds to pRB/p107.
E8 ?????
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Vírus do Papiloma Humano (HPV)
Características Gerais
Alto-Risco
HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58 e 59
Desenvolvimento de lesões baixo/alto grau e cancro do colo do útero
Desenvolvimento de outras neoplasias
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Vírus do Papiloma Humano (HPV)
Mecanismo de Carcinogénese
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Vírus do Papiloma Humano (HPV)
Mecanismo de Carcinogénese
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Vírus do Papiloma Humano (HPV)
Mecanismo de Carcinogénese
Major Events
Integração DNA viral no DNA do hospedeiro
Imortalização celular
Instabilidade genómica
Escape à Resposta Imunológica
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Vírus do Papiloma Humano (HPV)
Mecanismo de Carcinogénese
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Vírus do Papiloma Humano (HPV)
Mecanismo de Carcinogénese
Integração Viral
DNA Episomal: expressão de E2 regula a expressão de E6 e E7
DNA integrado: perda de E2 permite expressão desregulada de E6 e E7
Promove
Inibição replicação viral
Instabilidade genética
Confere vantagem selectiva para a proliferação de células
Ocorre na maioria dos casos de HSIL
Podem co-existir formas episomais com integradas
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Vírus do Papiloma Humano (HPV)
Mecanismo de Carcinogénese – E6
Moody and Laimonis, 2010
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Vírus do Papiloma Humano (HPV)
Mecanismo de Carcinogénese – E7
Moody and Laimonis, 2010
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Vírus do Papiloma Humano (HPV)
Mecanismo de Carcinogénese – E5
Expressa
Retículo endoplasmático
Complexo Golgi
Membrana Pasmática
Papel importante nos eventos
precoces da carcinogénese
Presente em lesoes do colo do útero
Ausente após integração
Funções
Ligação à ATPase e danificando a
formação de endolisossomas
Downregulating MHC class I and CD1d
Moody and Laimonis, 2010
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Vírus do Papiloma Humano (HPV)
Mecanismo de Carcinogénese
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Evasão Imunológica do HPV
Mecanismo de Infecção
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Evasão Imunológica do HPV
Persistência Infecção
Replicate in keratinocytes which are “programmed to die” (squames)
Viral release does not provoke inflammation
Inhibition of Interferon synthesis and signaling
Delayed activation of adaptive immune response
Compromised immune surveillance
(Cell mediated immunity is suppressed in non-regressing cells)
MAGARET STANLEY. IMMUNE RESPONSE TO HPV. VACCINE 24s1 (2006)
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Evasão Imunológica do HPV
Resposta Imunológica
RESPOSTA INATA
1ª linha resposta
Barreira Epitelial
Sistema Fagocitário
Citocinas
Sistema do Complemento
Sem memória associada
Promove resposta adaptativa por via
da interacção com Células
Apresentadoras de Antigénios
(células dendriticas/langerhans)
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Evasão Imunológica do HPV
Resposta Imunológica
RESPOSTA ADAPTADA
Celular
Células NK
Células CD8 citotóxicas
Macrófagos
Humoral
Células B memória
Plasmócitos
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Evasão Imunológica do HPV
Resposta Imunológica Anti-viral
NF-Kb
Major transcription factor that regulates
genes responsible for both the innate and
adaptive immune response
Plays a key role in regulating the immune
response to infection by upregulating genes
involved in T-cell development, maturation,
and proliferation
Increases the number of T cells
available for immune response
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Evasão Imunológica do HPV
Resposta Imunológica Anti-viral
TNFa
Pro-inflammatory ctyokine that promotes
a cascade of cytokines which mediate an
inflammatory response
Inibição da sinalização
para as células T
Ambiguous functions
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Evasão Imunológica do HPV
Resposta Imunológica Anti-viral
Interferon (IFN)
upregulates major histocompatibility complex
molecules, MHC I and MHC II, and increase
immunoproteasome activity.
Higher MHC II expression increases
presentation of viral peptides to helper T
cells;
Higher immunoproteasome activity increase
viral peptides processing for loading onto the
MHC I molecule;
Higher MHC I expression increases
presentation of viral peptides to cytotoxic T
cells;
Increases the recognition and killing
of infected cells by T cells.
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Evasão Imunológica do HPV
Resposta Imunológica Anti-HPV
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Evasão Imunológica do HPV
Resposta Imunológica Anti-HPV
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Evasão Imunológica do HPV
Em suma...
HPV replication does not induce:
necrosis
cytolysis
viraemia
Terminally differentiated cells are not part of immune surveillance
HPV E6 and E7 down regulates IFN-gamma
HPV E5 down regulates MHC class I
Despite weak immune response:
Most HPV cleared within 2 years
Cell mediated immunity
48. +
HPV e
Resposta
Imunológica
Hugo Sousa
BScH Microbiology, MSc Oncology
PhD Student, MD Student
_________________________________________
Serviço Virologia – Lab Biologia Molecular
Grupo Oncologia Molecular
IPO Porto FG EPE
Notas do Editor
• 1842: Rigoni-Stern reports that nuns have much lower incidence of cervical cancer than prostitutes • 1951: Successful in vitro culture of “HeLa” cells derived from a lethal cervical cancer (patient Henrietta Lacks) • 1983: Harald zur Hausen discovers new HPV types (types 16 and 18) lurking in HeLa cells and other cervical cancer cells. New cancer-associated types took 89 years to identify because they ’re not associated with overt symptoms like warts • 2008: Harald zur Hausen wins Nobel Prize for his work establishing a causal link between HPVs and cervical cancer
Disulfiram, olmesartan and dithiocarbamates can inhibit the nuclear factor-κB (NF-κB) signaling cascade upregulate major histocompatibility complex molecules, MHC I and MHC II, and increase immunoproteasome activity. Higher MHC I expression increases presentation of viral peptides to cytotoxic T cells, while the immunoproteasome processes viral peptides for loading onto the MHC I molecule, thereby increasing the recognition and killing of infected cells by T cells. Higher MHC II expression increases presentation of viral peptides to helper T cells
Disulfiram, olmesartan and dithiocarbamates can inhibit the nuclear factor-κB (NF-κB) signaling cascade upregulate major histocompatibility complex molecules, MHC I and MHC II, and increase immunoproteasome activity. Higher MHC I expression increases presentation of viral peptides to cytotoxic T cells, while the immunoproteasome processes viral peptides for loading onto the MHC I molecule, thereby increasing the recognition and killing of infected cells by T cells. Higher MHC II expression increases presentation of viral peptides to helper T cells
Disulfiram, olmesartan and dithiocarbamates can inhibit the nuclear factor-κB (NF-κB) signaling cascade upregulate major histocompatibility complex molecules, MHC I and MHC II, and increase immunoproteasome activity. Higher MHC I expression increases presentation of viral peptides to cytotoxic T cells, while the immunoproteasome processes viral peptides for loading onto the MHC I molecule, thereby increasing the recognition and killing of infected cells by T cells. Higher MHC II expression increases presentation of viral peptides to helper T cells
Host immune response to early HPV infection. The HPV infects the basal/suprabasal keratinocyte. The infected cell is proliferated and transformed by the E5 protein. This cell is in the premalignant stage. The E5 protein ( ) is presented by MHC class I and class II. CD4+ T-cells recognize the presented E5 antigenic epitope and are activated. The activated CD4+ T-cells activate CD8+ T-cells resulting in differentiation to the E5-specific CTL. This CTL specifically kills the E5 presenting premalignant cells.