DECREASE IN THE ALPHA(1)-PROTEINASE INHIBITOR SPI3 IN EQUINE BRONCHOALVEOLAR LAVAGE FLUID

The alpha(1)-proteinase inhibitors of trypsin, Spi1, Spi3A, and Spi3B, in bronchoalveolar lavage fluid (BALF) and serum of horses were separ ated by electrophoresis, and their proportions were quantified in 12 c ontrol horses and 12 with chronic obstructive pulmonary disease (COPD) . A significantly lower proportion of Spi3B (P < 0.05) and higher prop ortion of Spi1 (P < 0.02 to P < 0.01) were detected in BALF, compared with serum, in control and COPD-affected horses and appeared to be att ributable to reduced Spi3 activity in BALF. There was no significant d ifference between the control and COPD groups in this respect, indicat ing that the decrease in Spi3 may be a physiologic phenomenon. The dif ferences observed may be associated with proteolytic damage to or pref erential complex formation by Spi3.