Marked accumulation of IgG producing plasma cells occurs in lungs of <i>c</i>SiO₂-exposed NZBWF1 mice.

<p>Representative immunohistochemical photomicrographs of IgG in lungs of NZBWF1 mice. Photomicrographs taken at low magnification are shown in A and B whereas images at high magnification are shown in C and D. Vehicle-exposed mice did not indicate positive IgG staining (A,C). <i>c</i>SiO₂ induced marked infiltration of IgG-laden lymphocytes peripheral to both blood vessels (bv) and bronchiole airways (BA) (black arrows in B, white arrows in D). IgG was also detected extracellularly within alveolar parenchyma (ap) (stippled arrows in B, black arrows in D).