FIG. 2.

Effects of vessel geometry on IFN-γ response. (A) Data are presented as the mean OD₄₅₀ ± standard error of the mean (SEM) for IFN-γ responses to various stimuli (indicated on the x axis) in blood samples from M. bovis-infected cattle (n = 5; aerosol infected; United States) in 24-, 48-, or 96-well flat-bottomed plates as well as 96-well round-bottomed plates. Responses did not differ (P > 0.05) between vessel geometry types. (B) IFN-γ responses to PPD B, PPD A, SEB, or PBS (n = 23; United Kingdom; 16 cattle naturally infected with M. bovis, 5 experimentally infected cattle, and 2 uninfected cattle) were compared to determine the effects of 24- versus 96-well-plate formats. There was a highly significant correlation of responses between 24- and 96-well-plate formats, with a slope close to 1 (Spearman r = 0.9836; P < 0.0001).