Bioprocessing of Viral Vaccines (Amine Kamen)

2 ^{Introduction to virology}

Shantoshini Dash

Viral Vectors and Vaccines Bioprocessing Group,

Department of Bioengineering, McGill University, Montréal,

QC, Canada

CONTENTS

2.1 Introduction.....................................................................................................17

2.1.1 What Are Viruses?.............................................................................17

2.1.2 Virus Characteristics ..........................................................................18

2.1.3 Virus Evolution and Classification....................................................18

2.2 Structure and Genome....................................................................................19

2.2.1 Virus Structure and Function.............................................................19

2.2.1.1 Capsid ..................................................................................19

2.2.1.2 Envelope ..............................................................................19

2.2.2 Viral Genome .....................................................................................19

2.2.3 Viral Genome Transcription Via Intermediates................................20

2.3 Viral Infection Cycle......................................................................................22

2.3.1 Lytic Cycle .........................................................................................22

2.3.2 Lysogenic Cycle.................................................................................23

2.3.3 Infection in Eukaryotic Host..............................................................24

2.4 Virus-Host Interactions ..................................................................................28

2.4.1 Types of Virus-Host Interactions.......................................................29

2.4.2 Components of a Host Cell Interacting with Viral Elements...........29

2.4.3 Types of Infection..............................................................................30

2.4.4 Key Elements of a Viral Infection ....................................................31

2.4.5 Disease Occurrence............................................................................31

References................................................................................................................32

2.1

INTRODUCTION

2.1.1

WHAT ARE VIRUSES?

Viral infections are known to cause diseases that may or may not require hospitali-

zation; but also, they are the leading cause of a heavy mortality rate, including other

health complications. Viral infection proves a greater threat to human health that can

be least controlled [1]. Viruses, the causative agents of viral infections, are small,

subcellular microorganisms, extremely dependent on host cells and are known as

obligate intracellular and parasites. They can infect any form of life (plants, animals,

bacteria, fungi). While the first virus discovered was in 1892, known as the TMV

DOI: 10.1201/9781003229797-2