  Tests of the T, CP and CPT symmetries in the neutral kaon system are
performed by the direct comparison of the probabilities of a kaon transition
process to its symmetry-conjugate. The exchange of in and out states required
for a genuine test involving an anti-unitary transformation implied by
time-reversal is implemented exploiting the entanglement of $K^0\bar{K}{}^0$
pairs produced at a $\phi$-factory. A data sample collected by the KLOE
experiment at DA$\Phi$NE corresponding to an integrated luminosity of about 1.7
fb$^{-1}$ is analysed to study the $\Delta$t distributions of the $\phi\to
K_{S}K_{L}\to \pi^+\pi^- \: \pi^{\pm}e^{\mp}\nu$ and $\phi\to K_{S}K_{L}\to
\pi^{\pm}e^{\mp}\nu \: 3\pi^0$ processes, with $\Delta$t the difference of the
kaon decay times. A comparison of the measured $\Delta$t distributions in the
asymptotic region $\Delta t \gg \tau_{S}$ allows to test for the first time T
and CPT symmetries in kaon transitions with a precision of few percent, and to
observe CP violation with this novel method.
