Mutual Defense Alliance
The countries that made up the Central Powers were Germany, Austria-Hungary, Bulgaria, and Turkey.
The countries that made up the Allied Powers or Triple Entente were made up of, Britain, France, and Russia.
Over time though, the Triple Entente grew to 27 allies and associates.
America During the War
The treaty stated that if Italy were attacked by France, Austria-Hungary and Germany would would help help them with their defenses.
Also, Italy would help Germany if they were attacked by France.
Later Italy and France reached an agreement that they each would stay neutral in an event of an attack on the other.