  The universality of free fall, the weak equivalence principle (WEP), is a
cornerstone of the general theory of relativity, the most precise theory of
gravity confirmed in all experiments up to date. The WEP states the equivalence
of the inertial, $m$, and gravitational, $m_g$, masses and was tested in
numerous occasions with normal matter at relatively low energies. However,
there is no proof for the matter and antimatter at high energies. For the
antimatter the situation is even less clear -- current direct observations of
trapped antihydrogen suggest the limits $-65 < m_g / m < 110$ not excluding the
so-called antigravity phenomenon, i.e. repulsion of the antimatter by Earth.
Here we demonstrate an indirect bound $0.96 < m_g/m < 1.04$ on the
gravitational mass of relativistic electrons and positrons coming from the
absence of the vacuum Cherenkov radiation at the Large Electron-Positron
Collider (LEP) and stability of photons at the Tevatron collider in presence of
the annual variations of the solar gravitational potential. Our result clearly
rules out the speculated antigravity. By considering the absolute potential of
the Local Supercluster (LS), we also predict the bounds $1 - 4\times 10^{-7} <
m_g/m < 1 + 2\times 10^{-7}$ for an electron and positron. Finally, we comment
on a possibility of performing complementary tests at the future International
Linear Collider (ILC) and Compact Linear Collider (CLIC).
