  Binary pulsar systems emit potentially detectable components of gamma ray
emission due to Comptonization of the optical radiation of the companion star
by relativistic electrons of the pulsar wind, both before and after termination
of the wind. The recent optical observations of binary pulsar system PSR
B1259-63/LS 2883 revealed radiation properties of the companion star which
differ significantly from previous measurements. In this paper we study the
implications of these observations for the interaction rate of the unshocked
pulsar wind with the stellar photons and the related consequences for fluxes of
high energy (HE) and very high energy (VHE) gamma rays. We show that the signal
should be strong enough to be detected with Fermi close to the periastron
passage, unless the pulsar wind is strongly anisotropic or the Lorentz factor
of the wind is smaller than $10^3$ or larger that $10^5$. The higher luminosity
of the optical star also has two important implications: (i) attenuation of
gamma rays due to photon-photon pair production, and (ii) Compton drag of the
unshocked wind. While the first effect has an impact on the lightcurve of VHE
gamma rays, the second effect may significantly decrease the energy available
for particle acceleration after termination of the wind.
