Correlated basis function theory and Fermi hypernetted chain technique are extended to study medium-heavy, doubly closed shell nuclei in the jj coupling scheme, with different single-particle wave functions for protons and neutrons and isospin-dependent two-body correlations. Central semirealistic interactions are used. Ground-state energies, one-body densities, distribution functions and momentum distributions are calculated for 1 2 C, 1 6 O, 4 0 Ca, 4 8 Ca and 2 0 8 Pb nuclei. The values of the ground-state energies provided by isospin-dependent correlations are significantly lower than those obtained with isospin-independent correlations. In finite nuclear systems, the two-body Euler equations provide correlation functions variationally more effective than those obtained with the same technique in infinite nuclear matter.