Different clones of both Th1 and Th2 cells are specific for different targets
Clones of Th1 and Th2 cells specific for acetylcholine receptors and probably MuSK are relevant in the case of MG.
Generally, activated Th1 cells produce proteins called cytokines (for example, IL-2) which have inflammatory effects. They also help in the production of antibody subclasses which are good at activating the complement system. The complement system destroys cells which a specific antibody has bound to (for example, cells expressing the acetylcholine receptor and/or MusK in the case of MG).
Activated Th2 cells produce cytokines (for example, IL-4) which are anti-inflammatory. IL-4 also stimulates differentiation of Th3 cells, which secrete TGF-β and are involved in immunosuppressive mechanisms. Activated Th2 cells also help in the production of antibody subclasses which are poor at activating the complement system.
This is very complicated but these three free-access reviews might help.
Myasthenia gravis: past, present, and future
https://www.hindawi.com/journals/ad/2012/874680/
Changes in inflammatory cytokine networks in myasthenia gravis : Scientific Reports