  In the framework of the generalized tight binding method we have calculated
the quasiparticle band structure and the spectral functions of the undoped
cuprates like $La_2 CuO_4$, $Sr_2CuO_2Cl_2$ etc. Due to spin fluctuations the
in-gap state appears above the top of the valence band in the undoped
antiferromagnetic insulator similar to in-gap states induced by hole doping. In
the ARPES experiments the in-gap states can be detected as weak low energy
satellites.
