PHAR2210 Lecture Notes - Lecture 21: Viral Shedding, Viral Load, Aciclovir
Document Summary
Specific challenges in antiviral therapy: viruses are cellular parasites, do not carry out metabolic processes. Lipoprotein envelope : often include host cell membranes (phospholipids and proteins) some viral glycoproteins. Protein shell (capsid) facilitates passage between cells: varies in constituent peptides and number of layers, etc, genome may comprise ss- or ds-dna or rna size varies (smaller genome = more host- dependent" virus) Life cycle begins with dissociation of dna or rna from protein coat after entry into infected cell: genome is then copied. In dna viruses, dna is template for its own replication and for viral rna (used for the synthesis of viral proteins) Phosphorylated drug metabolites selectively block viral replication: much higher drug concentrations inhibit host cell dna synthesis. Acyclovir: acyclic deoxyguanosine analogue, active against herpes dna viruses (e. g. ophthalmic & mucocutaneous hsv and cmv, drug uptake enhanced in hsv-infected cells.