Figure 8.

Pulmonary hypertension (PH) can be caused by autoantibody passive transfer from monocrotaline (MCT) rats into naive rats. (A) Naive rats injected with either preimmune sera, adjuvant (saline) alone, or adjuvant mixed with control human IgG (B) do not develop pulmonary vascular remodeling or PH. Lung (left and middle images) and heart (right images) histology is normal, as is pulmonary artery pressure (PAP) in these rats. (C) Lung remodeling and heart fibrosis with elevated PAP in rats injected with plasma (C) or purified IgG (D) from MCT rats. Note the more intense blue staining in heart sections from rats receiving autoantibody transfer (far right images, C and D). (E) High titers of IgG in rats 4 weeks after cell immunizations or passive antibody transfers have ceased. Note low titers in control rat groups. IgG from rats, 4 weeks after apoptotic lung cell immunizations or autoantibodies have ceased, label nuclei and perinuclear compartments of cultured pulmonary artery fibroblasts. 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. Cell cultures and ELISAs were performed in three separate experiments in triplicate with rat plasmas from the indicated rats per group, compared with n = 3 control media experiments. All images, original magnification: ×100; bars = 20 μm where applicable. BALT = bronchus-associated lymphoid tissues.