Dr. Mohammad Al-Sweify
first isolated in 1953 in a human adenoid cell culture.
~ 47 serotypes are human pathogens.
RTI, conjunctivitis (pinkeye), hemorrhagic cystitis,
Adenovirus is being used to as vector to deliver DNA
for gene replacement therapy (e.g., cystic fibrosis).
Structure and replication
Adenoviruses are double-stranded DNA,
nonenveloped, icosadeltahedrons, 70-90 nm.
12 pentons, at each of the vertices, each
with a base and a fiber.
The fiber contains the viral attachment
proteins and act as a hemagglutinin.
The pentons and fibers also carry type-
specific antigens (47 serotypes).
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Structure & Replication..cont..
Adenovirus encodes DNA polymerase.
Also, a proteins that suppress host immune
and inflammatory responses.
One replication cycle takes 32-36 h 10,000
~100,000 fiber receptors on each cell.
Same receptor used by many Coxsackie B viruses.
Some adenoviruses use MHC I mol. as a receptor.
Structure & Replication..cont..
Internalization: by receptor-mediated endocytosis in
It lyses the endosomal vesicle
capsid delivers the DNA genome to the nucleus.
The penton and fiber proteins of the capsid are toxic
to the cell and can inhibit cellular macromolecular
Adenovirus causes lytic (muco-epithelium), persistent
and latent infections (lymphoid, adenoid, tonsils,
Peyer’s patche) reactivation in ISP.
The virus infects oropharynx, respiratory and enteric
organs epithelium, depending on fiber proteins that
determine the target cell specificity.
Toxic penton base protein inhibits cellular mRNA
transport and protein synthesis cell rounding, and
CPE of adenovirus: a dense, central intranuclear
inclusion consisting of viral DNA and protein.
Mononuclear cell infiltration and epithelial cell
Immunity to adenoviruses
Antibody is important for:
resolving lytic infections
protects from reinfection with the same serotype.
Cell-mediated immunity is important in limiting virus growth.
Mechanisms to evade host defenses (to persist in the host):
small virus-associated RNAs (VA RNA) prevent activation of
IFN-induced inhibition of viral protein synthesis.
Viral E3 and E1A proteins block apoptosis induced by
cellular responses to the virus or by T cell or cytokine (e.g.,
Some strains can inhibit Tc-cell action by preventing proper
expression of MHC I molecules no antigen presentation.
Adenov. resist drying, detergents, GIT juices, and
even mild chlorine treatment
Can be spread by aerosol, fecal-oral route, close
contact, by fomites (including towels and medical
instruments), and in swimming pools.
Fingers spread virus to eyes.
Adenov. may be shed intermittently and over long
periods from pharynx and in feces.
Most infections are asymptomatic spread in the
RT clinical illnesses by adenoviruses:
1. Pharyngitis alone occurs in young children<3 y.
It may mimic streptococcal infection.
Affected patients have mild, flulike symptoms (including
nasal congestion, cough, coryza, malaise, fever, chills,
myalgia, and headache) that may last 3-5 d.
2. Pharyngo-conjunctival fever in children and adults.
RT clinical illnesses by adenoviruses..continued..
3. ACUTE RESPIRATORY DISEASE: a syndrome consisting of
fever, cough, pharyngitis, and cervical adenitis.
Usually caused by adenovirus serotypes 4 and 7.
high incidence of infection of military recruits.
4. OTHER RESPIRATORY TRACT DISEASES
Adenoviruses cause cold-like symptoms, laryngitis, croup,
They can also cause a pertussis-like illness in children and
adults that consists of a prolonged clinical course and true
Culture from clinical specimen on
primary human embryonic kidney cells,
or HeLa cells 2-20 days lytic infection
with characteristic nuclear inclusions
Immunoassays: FA and ELISA
PCR and DNA probe analysis
Serologic test: not used.