  Highly accurate numerical results for single-particle spectrum and order
parameter are obtained for the magnetically ordered Kondo lattice by means of
the dynamical mean-field theory combined with the continuous-time quantum Monte
Carlo method. Hybridized energy bands involving local spins are identified in
the N\'{e}el state as a hallmark of itinerant antiferromagnetism. At the
boundary of the reduced Brillouin zone, the two-fold degeneracy remains in
spite of the doubled unit cell. This degeneracy results if the molecular field
felt by localized spins has identical magnitude and reversed direction with
that of conduction electrons. The persistent Kondo effect is responsible for
the behavior. The antiferromagnetic quantum transition occurs inside the
itinerant regime, and does not accompany the itinerant-localized transition.
