Viruses and infection Flashcards
What must viruses do in order to transmit?
Replicate inside the host
Viruses must evade or suppress host responses
What is the host environment like?
Hostile
Innate and adaptive immune responses
Cells are inherently antiviral - virus sensing
Why do symptoms of viral disease arise?
Virus wanting to transmit - cough and diarrhea
Host responding to virus - fever
What is the shape of HIV?
Cone-shaped
What cells does HIV infect?
Activated CD4 T cells
Where on the CD4 T cells do HIV bind?
CCR5 co-receptors
Course of HIV progression
High level of viremia at beginning of the disease
Viral set point is reached
CD4 cell death and viral replication remains high byt CONSTANT
Does the viral set point vary from person to person?
Yes
What happens to the course of HIV progression without treatment?
CD4 levels continue to drop
Too low levels = immunocompromised
Susceptibel to opportunistic infections
AIDS develops and eventually death
What is a common feature of RNA viruses?
Vast turnover
Why do RNA viruses have such a high turnover?
RNA polymerase and reverse transcriptase don’t have the proofreading and error correcting functions as DNA polymerase
Every time a virus divides, mutations or errors happen to the structure
What is a quasispecies?
Accumulation of diversity of viruses
Viruses related by a single or multiple mutations
What are the implications of the vast turnover of viruses?
Profound implications for
Immunity
Developing vaccines
Drug therapy
What is a phylogenetic tree?
Tree showing the varying HIV sequences within a single individual
What is the difference between the flu and HIV?
HIV develops mutations within a host
Flu does not develop mutations within a host