Immunological injury in "shipping fever" pneumonia of cattle.

Electron opaque deposits were found on the alveolar capillary walls, luminia of alveolar capillaries, subendothelium and interstitium of four out of 10 Holstein dairy cattle with past shipping histories. The deposits were positive for anti-IgG bovine immunoglobulin by fluorescent antibody technique. Evidence is presented that antigen antibody complexes may play an important role in bovine respiratory diseases.