FIG. 1.

PBMC populations from two experimentally infected animals (01 and 97) and two noninfected controls (6063 and 2701) were stimulated in vitro with M. bovis (10⁶ CFU/ml), MBSE (4 μg/ml), or PPDb (4 μg/ml). Control (no antigen) and concanavalin A (ConA)-stimulated cultures were also included. Results represent lymphocyte proliferation assessed by [methyl-³H]thymidine incorporation at various time points and are expressed as mean counts per minute (cpm) of triplicate values ± standard errors.