Nothing really reverses charge in electrons to form positrons, (and same goes for protons and anti-protons). The difference is in the quarks they are made of. For example, protons are made of two Up and one Down quark. The neutron is made of two Down and one Up quark. The Up quarks have a 2/3 positive charge and the Down has a 1/3 negative charge. So the different combinations of quarks will give you different overall charge for a given particle.
Neutrinos and antinutrinos (they, unlike protons and anti-protons, differer in orientations of spin and linear momentum), do not interact with matter because they are too small, uncharged and because neutrinos are electrically neutral, they are not affected by the electromagnetic forces which act on electrons. Neutrinos are affected only by a "weak" sub-atomic force of much shorter range than electromagnetism, and are therefore able to pass through great distances in matter without being affected by it.