  We review some recent progress in the study of electroweak interactions in
nuclei within the SuSAv2-MEC model. The model has the capability to predict
(anti)neutrino scattering observables on different nuclei. The theoretical
predictions are compared with the recent T2K $\nu_\mu-^{16}$O data and good
agreement is found at all kinematics. The results are very similar to those
obtained for $\nu_\mu-^{12}$C scattering, except at low energies, where some
differences emerge. The role of meson-exchange currents in the two-particle
two-hole channel is analyzed in some detail. In particular it is shown that the
density dependence of these contributions is different from what is found for
the quasielastic response.
