Heat grill. In medium bowl, combine all ingredients except bread; mix well.
When ready to grill, place bread halves, cut side down, on gas grill over medium heat or on charcoal grill 4 to 6 inches from medium coals. Cook 5 to 6 minutes or until lightly toasted.
Remove bread from grill. Spread cheese mixture evenly on cut sides of bread. Return to grill, cheese mixture side up; cook an additional 6 to 7 minutes or until cheese mixture bubbles around edges and center is hot.