Common Cold

What is the most important viral protease of the picornaviridae genome and what is its function?

3Cpro is the most important becuase it serves as the primary protease and mediator of viral protein production and maturation.

What is the host cell receptor that SARS targets for attachment?

ACE 2 receptors, or Angiotensin Converting Enzyme receptors.

In what cell types is adenovirus most likely to enter into a latent life cycle?

Adenoids, Tonsils, and Peyer's Patches.

Is the genome of the Adenovirus released into the cytosol or nucleus duirng an infection?

Adenovirus is a DNA virus, and therefore the genomme is released into the nucleus.

Conjunctivitis is most commonly cause by what virus?

Adenovirus.

Pharyngoconjuctival fever is almost always cause by what virus?

Adenovirus.

Which type of Adenoviruses vause respiratory infections?

Adenoviruses Type 1-7/

What is the genomic structure and virion morphology of Adenoviruses?

Adenoviruses are naked icosohedral Double Stranded DNA viruses.

How does rhinovirus, and all picornaviridae, make entry into the cell, and what viral protein is involved in attachment to the host cell?

All picornaviridae inject their genome into the host cell while leaving the capsid behind. Attachment is achived via Vp1.

Usually positive sense RNA viruses have icosohedral capsids, what is the one exception to this rule?

All the viruses of Coronoviridae have helical capsids....and are therefore enveloped as well.

What host cell receptor does Human Corona Virus target for attachment?

Aminopeptidase N, or APN receptor.

What host cell receptor is used by both B and Adenovirus?

CAR

What age group is most susceptible to RSV infections?

Children under 5

What is the most common disease caused by Human Corona Virus?

Common COld

If envaloped viruses are acid labile, then why is Coronaviridae acid stable, even through it has an envalope?

Coronaviridae have a dense layer of glycoproteins covering their envelope which functions to sheild the envelope from acid degradation.

What is the genomic structure and virion morphology of Corona viruses?

Coronoa viruses are positive sense RNA viruses with helical nucleocapsids. All viruses with helical nucleocapids have envelopes.

CAR is a receptor used by what two viruses to attach and enter the host cell?

Coxsackie B and Adenoviruses.

In Adenoviruses, what does the E1A gene code for and what is the purpose of this protein?

E1A gene codes for E1A transactivator which functions to increase protein synthesis by inhibiting host cell pRB.

Which Adenovirus viral gene encodes for proteins that inhibit host p53, and what is the consequence of this inhibition?

E1B blocks apoptosis induced by p53 by binding to it and inhibiting is ability to promote cell death.

True or False. Infection with adenoviruses does not create life long immunity because the infection is generally short lived and irradicated by the innate immunse system.

False. Life long immunity is obtained against that particular strand of Adenovirus.

In Respiratory Syncytial Virus, what surface protein is responsible for mediating its attachment to respiratory epithelial cells?

G protein.

What host cell surface proteins does Human Metapneumovirus ( HMPV) use for viral attachment?

GAGs

Which corona virus attaches the to host cell via Aminopeptidase N receptor?

Human Corona Virus

Why are infections of the human corona virus localized to the upper respiratory tract where as SARS and MERS of the same family can cause systemic infections?

Human corona virus has an optimal temperature for growth between 33 and 35 celcius whcih is found in the URT. SARS and MERS are able to replicate at 37 degrees and therefore can grow anyhere in the body.

What recpetors does Rhinovirus target on host cells?

ICAM-1 andLDL receptors.

In a latent life cycle, where andin what form does Adenovirus reside?

In a latent cycle, adenoviruses will reside in the nucelus in an inactive Epimere of circular DNA.

What are the two ways that adenoviruses can resist, or evade, host immune response?

Inhibition of PKR via Viral RNA: A host cell protein that shuts down protein synthesis in response to viral infections and Type 1 Interferons. Inhibition of MHC 1 expression: Only temporary as NK cells will eventually recognize decreased HLA-E xpression via CD94:NKG2A receptors and will initiate immune responses.

How does body temperature effect the localization of respiratory infections?

Many viruses have an optimal temperature range for growth that will limit, or localize, the respiratory region that they can infect.

What is the genomic structure and virion morphology of Paramyxoviridae?

Negative sense, helical nucelocapsid.

What virus is the primary cause of Croup?

Parainfluenza

What mechanism do members of Paramyxoviridae utilize to gain entry into the host cell?

Paramyxoviridae all express Viral Protein F, which allows them to enter the host cell via Fusion.

What is the genomic structure and virion morphology of Picornoviruses?

Postitive sense RNA, naked Icosohedral

What is unique about RSV in regards to how it spreads to infect other cells?

RSV has F protein which allows it to move directly from cell to cell without having to enter the extracellular space.

What is the #1 cause of bronchiolitis?

RSV, especially in newborns or premature infants.

G protein mediates the attachment of which virus to respiratory epithelial cells?

Respiratory Syncytial Virus.

What are the primary types of target cells for Human Metapneumovirus ( HMPV)?

Respiratory epithelial cells, airway macrophages, and dendritic cells.

Which viruses that cause the common cold attach to host cells via ICAM-1?

Rhinovirus and Corona Virus

Why does rhinovirus rarely infect the lower respiratory tract?

Rhinovirus grows best at temperatures around 91 degress which is the temperature of upper respiratory tract. It is also cleared by immune defenses extremrly quickly and cannot spread to lower respiratory tract.

How does Rhinovirus differ from other picornaviridae member in regards to its stability and method of transmission?

Rhinovirus is acid labile and cannot be transmitted via fecal oral route. All other picornaviridae viruses are acid stable and can be transmitted fecal oral.

What is the number one cause of the common cold?

Rhinovirus.

Why is a person who fends off a rhinovirus unlikely to retain life long immunity to that strain?

Rhinoviruses are usually eliminiated by the innate immune system and therefore do not create any memory T or B cells.

What is unique about picornaviridae with regards to how its genome is translated and proteins are produced?

Their genome is translated as one long continuous polypeptide that must undergo at least 2 rounds of cleavage via 3Cpro in order to become funcitonal.

True or False All negative sense RNA viruses have helical capsids and therefore have an envelope.

True.

True or False. Adenoviruses can cause a lytic or latent infection depending on the host cell.

True.

True or False. All helical capsid viruses are enveloped.

True.

How are mature Human Corona viruses released form the infected host cell?

Via Exocytosis.

How is Adenovirus transmitted?

Via respiratory droplets.

Watch this video for virus strucutre, genome, and exceptions to rules.

https://www.youtube.com/watch?v=Df_qAFF58Ec

What is the function of p53 in host cells?

p53 is a safe gaurd mechanism that induces apoptosis in the cell becomes damaged beyond repair or becomes infected.

What is the function of pRB in host cells?

pRB is a tumor suppressor protein that prevents the cell from undergoing divison unless the conditions are right.