The mucosal surface of the respiratory tract has an operable immune sy
stem, specially designed for producing immunoglobulins (antibodies); h
owever, it has not been harnessed effectively yet to provide local, im
munospecific protection against many microbes that enter. Respiratory
host responses in humans have been used in this review where possible.
New research approaches seem necessary to manipulate the physical and
immunologic barriers in the respiratory tract and this may require di
fferent antigen preparations, better and more specific vehicles for de
livery and selective enhancement of cytokines and interleukins in the
mucosa. The immunologic tools are available and need to be explored mo
re in the human model.