ANTIVIRAL ACTIVITIES OF PEPTIDES WITH SEQUENCES RELATED TO THE CYTOPLASMIC DOMAIN OF THE RESPIRATORY SYNCYTIAL VIRUS GLYCOPROTEINS

A set of peptides from 6-10 amino acids in length with sequences corre sponding to the respiratory syncytial virus (RSV) attachment glycoprot ein, G, has been found to inhibit secretion of virus particles from tw o human cell lines infected with RSV, Peptides of similar lengths with sequences related to the fusion (F) protein were not effective. A mod ified assay for syncytia formation was used to measure infectious part icles and we found that cell-free infectious RSV was inhibited by thos e same peptides that blocked particle release, However, only about 5-2 0% of the total infectious virus formed in the cultured cells was rele ased from the cells - the remaining was assayable only after lysis of the infected cells. Formation of this major fraction of infectious, ce ll-associated RSV was not affected by the peptides. The inhibitory pep tides were ineffective in blocking release of infectious virus from ce lls infected with influenza, vesicular stomatitis and Semliki Forest v iruses, Only a set of specific amino acids in these peptides were inhi bitory and they consisted of a very hydrophobic sequence that also req uired a cysteine residue.