CD4 and Increased total eosinophil count: The results from the present study highlights: (1) unlike RSV A subtype, a.a. residues 183–195 in Gcf of RSV B subtype do not function as CD4+ T cell epitope, (2) Gcfs from RSV B subtype, unlike RSV A subtype, do not induce eosinophilia after RSV B subtype challenge, and (3) Gcf derived from RSV A subtype containing modified CD4+ T cell epitope can protect mice against both RSV A and B subtypes without immunopathology.