Virology

VIROLOGY

Introduction to Virology Virology •

A virus is an obligate intracellular parasite containing genetic material surrounded by protein

•

Virus particles can only be observed by an electron microscope

Introduction to Virology Virology •

A virus is an obligate intracellular parasite containing genetic material surrounded by protein

•

Virus particles can only be observed by an electron microscope

•

Recognizing the shape, size, and structure o di!erent viruses is critical to the study o disease  – Viruses

have an inner core o nucleic acid surrounded surrounded by protein coat "no#n as an envelope  – $ost viruses range in sizes rom 2% & 2'% nanometers

Viral )roperti )roperties es • • • • •

Viruses are inert (nucleoprotein (nucleopr otein ) flterable Agents Viruses are obligate intracellular parasites Viruses cannot make energy or proteins independent o a host cell Viral genome are RNA or DNA but not both. Viruses hae a naked capsid or enelope !ith attached proteins

VIRA# $%R&'%&R  $*+ %R+IN*#*,-  • •

• •

•

virus particle + virion protein #hich coats the genome + capsid capsid usually symmetrical capsid  genome + nucleocapsid may have an envelope

Virion %he complete inectious unit o irus particle • $tructurally mature e/tracellular irus particles. •

•

.O/0 R1/I/0A31 0O VIRAL I4130IO

•

)rimary 5eenses  –

 /"in barrier 6dead "eratinized cells impervious to viruses7  – /"in has acids and other inhibitors produced by normal bacterial 8ora  – $ucociliary elevator •

Immune 5eense

•

Innate immune response 9 Intereron  – 9 3omplement  – 9 atural "iller cells  –

•

Adaptive immune response

•

Intererons 6I4s7 are a amily o eu"aryotic cell proteins classi;ed according to the cell o origin< I4=alpha and I4= beta are produced by a variety o virus=inected cells< 0hey>  –

;rst described in ?-'@ by Alic" Isaacs and Bean Lindenmann at the ational Institute or $edical Research in London  – 9 Act on target cells to inhibit viral replication<  – 9 5o not act directly on the virus<  – 9 Are not virus=speci;c<  – 9 Are species=speci;c 6e