IMMUNOLOGICAL PROPERTIES OF PLAQUE PURIFIED STRAINS OF LIVE ATTENUATED RESPIRATORY SYNCYTIAL VIRUS (RSV) FOR HUMAN VACCINE

Respiratory syncytial virus (RSV) causes severe lower respiratory trac t disease in infants, young children, and the elderly. Efforts to deve lop satisfactory live or inactivated vaccines have not yet been proven successful. Our research focuses on the development of four purified live attenuated RSV sub-type A human vaccine clones. Temperature sensi tive (ts) and attenuated purified clones of either cold-adapted (ca) R SV or high-passage (hp) RSV were administered intra-nasally (i.n.) to BALB/c mice and tested for immunogenicity. All four clones produced si gnificant anti-RSV F IgG(2a) and IgG(1) titres in the sera of mice, RS V-specific neutralizing titres higher than those produced by their wil d-type progenitor viruses, cytotoxic T-lymphocyte (CTL) activity, and total protection against wild-type (wt) viral challenge. These purifie d vaccine candidates await testing in humans to determine which contai n the required balance between immunogenicity and attenuation. (C) 199 8 Elsevier Science Ltd. All rights reserved.