The antigenic and genetic variability of bovine respiratory syncytial virus with emphasis on the G protein

Bovine respiratory syncytial virus (BRSV) and related human respiratory syncytial virus (HRSV) are major respiratory tract pathogens in calves and infants, respectively. Great attention is now paid to prevention of the disease caused by these agents. Glycoprotein G is the most variable viral protein and antigenic grouping of RSV isolates is based on distinct antigenic reactivity patterns determined with a set of G protein specific mAbs. Genetic variability of the G protein is used during epidemiology and epizootiology studies of HRSV and BRSV diseases, respectively. The constant genetic drift can be observed within G protein sequences. Both cell-mediated and antibody-mediated immune responses contribute to efficient protection against RSV infection. The neutralizing antibodies are induced by F and G proteins. The G protein fails to induce cytotoxic lymphocytes response and may causes aberrant Th2 response leading to enhancement of clinical symptoms in subsequently infected vaccines. The G as the most variable viral protein associated with immunopathologic effect is a critical factor in vaccine development.