Regional differences in the early mucosal immune response induced by primary inoculation of mice with respiratory syncytial virus.

Respiratory syncytial virus (RSV) is the most important cause of respiratory tract infection in infants. Little is known about the characteristics of critical immunologic inductive sites within respiratory-associated lymphoid tissues (RALT) upon RSV infection. We examined the kinetics and characteristics of early mucosal RSV-specific immune responses after primary inoculation of mice. We found that the initial production of virus-specific antibodies was restricted to the organized lymphoid tissues of RALT, such as nasal-associated lymphoid tissue (NALT), cervical and bronchial lymph nodes (CLN and BLN). In addition, virus-specific IgM was produced by B cells resident in CLN and BLN, but not NALT, of mice. Finally, we observed regional differences in the pattern of RSV-specific antibodies produced by RALT; B cells within NALT and CLN produced equivalent quantities of virus-specific IgG2a and IgG2b. However, an IgG2a response predominated in BLN. Together these data demonstrate regional differences in the early mucosal immune response to RSV. Further understanding of these differences may assist the development of RSV vaccines.