Am. J. Respir. Crit. Care Med., Vol 157, No. 1, Jan 1998, 324-327.
Effects of systemic and local immunization on alveolar epithelial permeability to protein in the rat [In Process Citation]
HG Folkesson, BR Westrom and BW Karlsson
Department of Animal Physiology, Lund University, Sweden.
This study aimed to characterize the effect on alveolar epithelial
permeability to protein as a result of immunization when animals were
reexposed to antigen. Antigen (bovine serum albumin [BSA]) and a related
bystander protein (human serum albumin [HSA]) were intratracheally
instilled into lungs of immunized rats and their passages across the
alveolar epithelium were measured as serum levels 16 h after instillation.
Nonimmunized control rats showed similar passages of both BSA and HSA. In
rats intradermally immunized against BSA, BSA was undetectable in serum,
whereas serum levels of HSA were markedly increased compared with those in
control rats. In rats immunized with BSA intratracheally, serum levels of
both BSA and HSA were unchanged compared with those in control rats. Serum
titers of specific IgG antibodies (anti-BSA) were measured and were higher
in intradermally immunized animals than in intrapulmonary immunized
animals, whereas no anti-BSA antibodies were detected in nonimmunized
control rats. Anti-BSA antibodies were detected only in lavage fluid from
intradermally immunized rats. These findings suggest that presence of
specific antibodies locally in the lungs may increase alveolar epithelial
permeability to protein. This finding may have clinical implications, e.g.,
for sensitive asthmatics, since increased nonspecific permeability caused
by local immune-related inflammation may result in further allergies.
