<p>I/St mice 6 wk after <i>M. tuberculosis</i> challenge (A) and B6 mice 16 wk after <i>M. avium</i> challenge (B) were injected with 60 mg/kg body weight of Hypoxyprobe™-1 and sacrificed 3 h later. Lung cryosections were obtained and developed for indirect peroxidase staining to detect hypoxia gradients (×200).</p