Final answer:
The cytokine that induces proliferation and differentiation of B and T cells, stimulates acute phase protein release, and induces fever is interleukin-1 (IL-1).
Step-by-step explanation:
The cytokine that matches the description of helping to induce proliferation and differentiation of B cells and T cells, stimulates the release of acute phase proteins, and acts on the hypothalamus to induce fever is interleukin-1 (IL-1). Interleukin-1 is well-known for its effects on immune and inflammatory responses, and it is part of a group of cytokines that can cause a fever by acting on the hypothalamus, as well as affecting B and T cells to mount an immunological response.