Viral Vector Presentation PDF

# Viral Vector Presented by: Manka Mary 1st M.Sc. Microbiology ## Introduction * Vector is a vehicle used to transfer the genetic material into a target cell. * A diagram of bacteriophage shows the capsid (head) containing DNA and the sheath, pin, baseplate and tail fib. * Viral vectors are too...

# Viral Vector Presented by: Manka Mary 1st M.Sc. Microbiology ## Introduction * Vector is a vehicle used to transfer the genetic material into a target cell. * A diagram of bacteriophage shows the capsid (head) containing DNA and the sheath, pin, baseplate and tail fib. * Viral vectors are tools used by molecular biologists to deliver genetic material into cells. * Diagram shows two types of viral vectors: * Virus or plasmids * Modified viral plasmids * Both are delivered to the host or viral packaging cells and result in more virus or viruses with modified genomes. ## Uses of Viral Vectors * Virus are obligate intracellular parasites. * Very efficient at transferring viral DNA into host cells. * Specific target cells depending on the viral attachment proteins. * Gene replacement: non-essential genes of virus are deleted and exogenous genes are inserted. ## Properties of Viral Vectors ### Safety: * Deletion of the viral genome critical for viral replication e.g helper virus. ### Low Toxicity. ### Stability: * Some viruses are genetically unstable and can rapidly rearrange their genomes. ### Identification: * Viral vectors are often give certain genes that helps identify which cells took up the viral gene e.g antibiotic resistance genes. ## Types of Viral Vectors ### DNA Viral Vectors: * Adenovirus * Adeno-Associated virus * Herpes virus ### RNA Viral Virus: * Lentivirus * Retrovirus ## Adenovirus * It causes common cold. * It is the double stranded DNA. * It is the naked virus and it has interactions proteins which to penetrate into host cell. * Diagram shows: * Fibre (receptor binding, haemagglutination) * Hexon (structural) * Penton base (penetration) * Core protein V * Terminal protein * Core protein VII * DNA genome ## Adeno-Associated virus * It is a small virus which infects humans. * The virus causes a very mild immune response, lending further support to its apparent lack of pathogenicity. * Diagram shows a colorful virus ## Herpes virus * This type of viral vector has the ability to deliver large-scale quantities of exogenous DNA. * The main role is maintenance of transgene expression. * Diagram shows the structure of herpes virus which includes: * Glycoproteins * Capsid * Envelope * DNA * Tegument ## Lentivirus * Lentiviruses are a type of retrovirus that are able to integrate into non-dividing cells and do not require mitotic cell division in order to function. * Instead, the genome enters the cell DNA via reverse transcription and is incorporated in a random position of the cell genome. * Diagram shows the processes happening inside a cell including. * Attachment * Fusion * Protein synthesis * Cytoskeleton * Nuclear pore * Endoplasmic reticulum * Early and late mRNAs * RNA polymerase * Viral DNA * Nucleus * Exocytosis ## Retrovirus * Retrovirus vectors are commonly used and known to integrate into the genome of the infected cell in a stable and permanent fashion. * Reverse transcriptase in the virus allows integration into the host genome. * Diagram shows: * Glycoprotein * Envelope * Capsid * Reverse transcriptase * Viral RNA ## Applications ### Gene Therapy: * Gene therapy is a technique for correcting defective genes responsible for disease development. * There are following delivery system for gene therapy: * Physical methods * Non-viral vectors * Viral vectors * Diagram shows the process of using viral vectors for gene therapy: * Cells are removed from patient * A virus is altered so that it cannot reproduce. * A gene is inserted into the virus * The altered virus is mixed with the cells from the patient. * The cells from the patient become genetically altered. * The genetically altered cells produce the desired protein or hormone * The altered cells are injected into the patient ### In Vaccination: * Viruses expressing pathogen proteins are currently being developed as vaccines against these pathogens, based on the same rationale as DNA vaccines. * A viral vaccine induces expression of pathogen proteins within host cells. Since viral vaccines contain only a small fraction of pathogen genes, they are much safer and sporadic infection by the pathogen is impossible. * Adenoviruses are being actively developed as vaccines. * Diagram shows the steps involved in vaccination using viral vectors * Genome of harmless virus is combined with gene from pathogen. This creates a recombinant virus which is used as a vaccine. * This recombinant virus is being injected into a person, thus vaccinating them. * This vaccine then interacts with different cells including the muscle, dendritic and skin cells and may cause a tumor. # Thank You