Proliferation and death rates are reduced in PL cows. The minimal proliferation (panel A) and death (panel B) rates were estimated from fitting the model to the data deduced from two independent experiments. PL, AS, and NI are, respectively, persistently lymphocytic, asymptomatic, and noninfected animals. Statistical analysis reveals that the proliferation and death rates are significantly reduced in PL cows compared to uninfected and asymptomatic in both experiments: average proliferation rates of B cells in PL cows lower than in uninfected and asymptomatic, confidence level: 90% in experiment 1 (*), 95% in experiment 2 (**). Average death rates of labeled B cells in PL cows were lower than in uninfected and asymptomatic, confidence level: 95% in experiment 1 (**), 95% in experiment 2 (**) (two-tailed Student t test in each case).