Figure 2.

Bronchus-associated lymphoid tissues (BALTs) in rats with pulmonary hypertension (PH) are highly organized and more vascularized compared with control animals. In PH versus control animals, CD3⁺ T cells and CD45RA⁺ B cells adopt distinct segregational localizations in PH BALT, and are encircled by OX-62⁺ dendritic cells, and CD11b⁺, CD11c⁺, and CD83⁺ cells (left column of images and top right images). VCAM⁺ structures are more evident in PH versus control animals, whereas aquaporin (AQP)-1–positive structures seemed to be proportional to BALT size in both PH and control animals (right column of images, middle). CD45RA⁺ cells did not colocalize with ki-67 immunoreactivity in either control animals or PH, even when control BALT sizes were large (lowest control left image, right column). Note robust ki-67–positive cells (red, lowest right image) in adventitial of bronchovascular space. Representative images and measurements taken from lung sections from n = 6 animals per group, with two to three sections per rat from three independent experiments. All images, original magnification: ×100; bars = 20 μm where applicable. CTL = control; MCT = monocrotaline; VCAM = vascular cell adhesion molecule.