Hold on there Jim! The body of Christ is every believer in this world that is in Christ through His shed Blood. They are the True Church.
Then there are those who have departed from the Cross and the Blood that saves calling themselves the Church. Apostates they are, and whom I am referring.
The Bible doesn't support this theology whatsoever. That theology wasn't formulated until the Reformers broke off from the Catholic church and tried to reconcile their split with the biblical teaching that God only leads 1 church.
Furthermore, the false church system in Rev. 17 with protesting daughter churches claim Christianity, but God says this system is worshiping Satan(Rev. 13:4). The idea that all "believers" constitute the true Church is a lie that is based on people completely disregarding what the Bible has to say. God's Church keep His laws(Rev. 14:12, 12:17), they understand bible prophecy and other biblical doctrines(Rev. 12:17, 19:10, Dan.12:10, Psa. 111:10), they believe in living by the OT and NT as Christ commanded(Matt. 4:4, Luk. 4:4, Deut. 8:3), and they are spiritual Jews(Rom. 2:29, Rev. 2:9, 3:9).
The false Gentile church in Rev. 17, on the other hand, cling to pagan traditions and beliefs that were cleverly whitewashed as "Christian", and they also reject God's commandments and His commanded festivals.
As much as they want to insist that they are Christian, the Bible says that the adherents of the counterfeit Gentile religion in Rev. 17 that masquerades as Christianity are not members of God's Church at all. Catholicism and Protestantism reject the biblical church model, they practice pagan festivals that are condemned in scripture, and they both preach gospels that are completely antithetical to the one Christ actually proclaimed(Matt. 4:23, Luk, 4:23, Acts 1:3), so it cannot ever rightfully be said that adherents of either one of these false religions constitute God's Church.
When the Bible says that Jesus built and leads 1 church in this world, that's exactly what it means: 1. The history in Rev. 2-3 contains the history of that 1 church and its 2,000 year war against the false Gentile religion calling itself "Christianity".