Final answer:
The CD antigen typical for helper T lymphocytes is CD4. The false statement about T cells is that MHC II is found on most body cells and MHC I only on immune cells; actually, MHC I is found on nearly all nucleated cells and MHC II on antigen-presenting cells.
Step-by-step explanation:
The CD antigen that is typical for helper T lymphocytes is CD4. Helper T cells are characterized by the expression of CD4 on their surface and are therefore referred to as CD4+ T cells. These cells play a crucial role in the immune response by releasing cytokines which help regulate the activity of other immune cells.
On the other hand, cytotoxic T cells, which are responsible for killing infected cells, are characterized by the expression of CD8 and are referred to as CD8+ T cells.