FIG. 1.

Tulathromycin induces cell apoptosis in calves challenged intratracheally with live M. haemolytica. (A) Fluorescent staining of bronchoalveolar lavage (BAL) samples fixed with 4% paraformaldehyde. Green represents TUNEL staining of apoptotic cells. Levels of apoptotic mono-/oligonucleosomes in BAL samples isolated from sham-treated (control), M. haemolytica-challenged calves (M. haem) and tulathromycin-treated calves challenged with M. haemolytica (M. haem + TUL) were measured using a cell death ELISA at 3 h (B) and 24 h (C) postinfection. Values were calculated as absorbance ratios versus values measured with cells from uninfected control calves. Values are means ± standard errors of the means. n = 5 to 8/group. *, P < 0.05.