Final answer:
Antibodies are not a part of the cellular immune system but are instead produced by B cells during the humoral immune response.
Step-by-step explanation:
The component of the body's cellular immune system that is not part of the adaptive immune system is D) Antibodies. While T lymphocytes (T cells), B lymphocytes (B cells), and Macrophages are all key cells in the adaptive immune system, antibodies themselves are instead the product of the adaptive immune response and are a part of the humoral immunity. B cells, or B lymphocytes, are responsible for producing antibodies when they transform into plasma cells upon activation. On the other hand, T cells are involved in cell-mediated responses where they may kill infected host cells or help activate other immune cells.