Ah yes, the "Christ Class". One of Russell's core doctrines was that "The Christ" was not Jesus, but Jesus plus the 144,000 "anointed":
The word Christ signifies anointed. Anointing means designation to official position in God’s arrangement. The Christ is the instrument or channel for the blessing of mankind. The Christ is composed of Jesus, the great and mighty head, and 144,000 members. --The Harp of God, 1921, p 187
You don't find such explicit reference to this view in current Watchtower writings, no doubt on account of Matt 24:4,5,24:
Jesus answered: "Watch out that no one deceives you. For many will come in my name, claiming, 'I am the Christ,' and will deceive many.
For false Christs and false prophets will appear and perform great signs and miracles to deceive even the elect—if that were possible.
Nowadays the doctrine is couched using less direct terminology. While no longer directly referred to as "The Christ", the 144,000 are still referred to as "anointed" (the Greek "Khristós", Christ, literally means "anointed"). And the 144,000 are still said to be "co-rulers" with Christ, "associate kings and priests", etc, who will, along with Christ, restore the rest of mankind to perfection:
*** w67 7/15 p. 447 The Removal of Mankind’s Chief Disturber ***
Christ and his 144,000 associate kings and priests will minister to mankind and raise them up from the imperfect state in which desires of the flesh have such a hold upon them.
*** w85 12/1 p. 17 par. 17 Declared Righteous as a Friend of God ***
During the Millennium, the enthroned Lamb, Christ Jesus, together with his 144,000 associate kings and priests, will apply a program of spiritual and physical “curing of the nations.”
*** w87 7/1 p. 24 par. 13 Divine Blessings for “the Ones Having Insight” ***
When, by the end of the Thousand Year Reign, Jesus and his 144,000 associate kings and priests have restored faithful humans to perfection, they will indeed have brought “many to righteousness.”
*** w07 9/1 p. 20 Highlights From the Book of Daniel ***
The anointed will ‘shine like the stars’ in the fullest sense during the Millennial Rule of Christ, when they share with him in applying the full benefits of the ransom to obedient mankind on earth.