Helper T Cell Recognition of Respiratory Syncytial Virus in Mice

National Institute for Medical Research, Mill Hill, London NW7 1AA, U.K. and 1 Department of Microbiology, University of Alabama, Birmingham, Alabama 35294, U.S.A. In this study we aimed to define the protein and viral subtype specificities of helper T h cells to respiratory syncytial virus (RSV). BALB/c mice were primed by infection with RSV, or with vaccinia viruses (VV) containing genes encoding several individual RSV proteins. Priming for T h cell memory was assayed by stimulating spleen cells in vitro with different RSV isolates and measuring RSV-specific interleukin 2 (IL-2) release by T cells into supernatants using an IL-2-dependent CTLL cell line. Splenocytes from mice primed intranasally with RSV exhibited RSV-specific T h cell memory, whereas those from unprimed mice did not. T h cell recognition was in part specific to the strain of RSV used in priming and in part cross-reactive between RSV strains. Intraperitoneal priming with RSV fusion protein-expressing VV or nucleoprotein-expressing VV induced a stronger RSV-specific T h cell response than the attachment glycoprotein-expressing VV which produced only slight T h recognition. No T h cell recognition of two non-structural proteins (1A and 1B) could be demonstrated. Keywords: RSV, helper T cells, interleukin 2 Received 16 July 1987; accepted 19 October 1987.