Percentages of CD5bright T cells among PBMCs isolated from control noninfected calves and calves infected with Mycobacterium avium subsp. paratuberculosis by the following methods: oral, intraperitoneal, oral with dexamethasone administration, and oral with mucosal scrapings from a cow with clinical disease. Percentages of CD5bright T cells during the 12-month study were measured within total PBMCs (A) and CD4+ T cells (B) stimulated with a whole-cell sonicate of Mycobacterium avium subsp. paratuberculosis (MPS). Data are expressed as means ± SEM. Significant differences between control and infection groups within given time points are represented by asterisks (**, P < 0.01; *, P < 0.05).