Local immunity in the pig respiratory tract. II. -- Relationship of serum and local antibodies.

Antibody passage from blood to respiratory secretions was studied on pigs. The animals were passively immunized and have a high anti-hog cholera serum antibody titer. With normal animals as with swine influenza animals, no serum antibody could be recovered neither in buccopharyngeal secretions nor in lung washings: it seems that in such conditions no detectable transudation occurs from blood to local secretions. Following intranasal inoculation of swine influenza virus or intramuscular injection of live attenuated hog cholera virus, local antibodies appear, which are considered to be locally produced.