Male and female C57BL/6 mice were exposed to a single dose of cSiO2 (1 mg), MWCNTs (50μg), or dispersion media (DM) vehicle control (50 μl), and euthanized 24-hours post-exposure. Whole lung lavage fluid (LLF) was collected for total cell counts (A), extracellular protein assessment (B), and cytometric analysis of immune cell populations within the airspace (C). Data represented as mean ± SEM, n = 4–12. * p < .05, ** p < .01, *** p < .001, **** p < .0001 compared to same-sex DM control, # compared to males of the same treatment.