system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Interleukin secreted by macrophages, stimulating lymphocytes is:
assistant
The correct answer is  Macrophages release IL-1 which stimulates the T-helper cells.
The T-cells in response proliferate and release IL-2 which in turn stimulates still further T-cell proliferation and B cell proliferation and differentiation into plasma cells.

Thus

Macrophages release→IL-1*
T-helper cells release→ IL-2*