Male and female C57BL/6 mice were exposed to cSiO2 (1 mg), MWCNTs (50μg), or dispersion media (DM) vehicle control (50 μl), once per week for 4 weeks and harvested 8 weeks after the last exposure. Concentrated first-pull lung lavage fluid (A) and plasma (B) was collected for cytokine expression analysis. Data represented as mean ± SEM, n = 4–5. * p < .05, ** p < .01, *** p < .001, **** p < .0001 compared to same-sex DM control, # compared to males of the same treatment.