Figure 2.

(a) Direct effect of exposure to the Libby Six-Mix asbestos on the proliferation rate of CH12.LX B-lymphocytes. Cells were exposed to 35 μg asbestos/cm2 or 1 μg LPS/ml (positive control) for 48 h and assayed by measurement of fluorescence at 530 nm. n = 6; Error Bars = Standard Error of the Mean (SEM). LPS as a positive control significantly (*p < 0.05) increased proliferation rate of the CH12.LX B-lymphocytes. (b) Direct effect of exposure to Libby Six-Mix asbestos on the isotype of antibody secreted by CH12.LX B-lymphocytes. Cells were exposed to 35 μg asbestos/cm2 for 72 h and then assayed by an isotype-specific ELISA. Data suggests that two populations of CH12.LX cells exist in the culture, i.e., these secrete either IgM or IgA. IgG is not expressed above the level of background; 1 μg LPS/ml (positive control) did increase production of each isotype measured. n = 3; Error Bars = SEM; *p < 0.05.