Analysis of DNA of Defective Herpes Simplex Virus Type 1 by Restriction Endonuclease Cleavage and Nucleic Acid Hybridization

Defective interfering particles have been found in stocks of many different animal viruses (Huang 1973). These particles do not contain a complete viral genome and are nonviable under conditions of single infection, being able to complete a growth cycle only in the presence of a viable “helper” virus. They are therefore propagated mainly in virus stocks grown at high multiplicities of infection. These particles also interfere with the growth of normal virus, resulting in lowered yields of infectious particles. Recently, Bronson et al. (1973) described the presence of variant particles in stocks of herpes simplex virus (HSV) which were repeatedly grown under conditions of high multiplicity of infection. They showed that these stocks contained particles with DNA of higher buoyant density in CsCl than that of the normal HSV DNA.