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Multiple Choice
Which type of cells stimulate both antibody-secreting cells and cytotoxic T cells during an immune response?
A
Natural killer (NK) cells
B
Helper T cells (CD4+)
C
Macrophages
D
B cells
Verified step by step guidance
1
Step 1: Understand the role of each cell type mentioned in the problem. Natural killer (NK) cells are part of the innate immune system and directly attack infected or cancerous cells without stimulating other immune cells. Macrophages are phagocytic cells that engulf pathogens and present antigens to T cells but do not directly stimulate both antibody-secreting cells and cytotoxic T cells. B cells produce antibodies but require activation by other cells.
Step 2: Focus on the role of Helper T cells (CD4+). These cells are part of the adaptive immune system and play a central role in coordinating the immune response. They release cytokines that activate B cells to become antibody-secreting plasma cells and also stimulate cytotoxic T cells to attack infected cells.
Step 3: Recall the mechanism of antigen presentation. Helper T cells are activated when they recognize antigens presented by antigen-presenting cells (APCs) such as macrophages or dendritic cells. This activation allows them to perform their coordinating role in the immune response.
Step 4: Connect the function of Helper T cells to the immune response. Once activated, Helper T cells interact with B cells to promote antibody production and with cytotoxic T cells to enhance their ability to kill infected cells. This dual role makes them essential for both humoral and cell-mediated immunity.
Step 5: Conclude that Helper T cells (CD4+) are the correct answer because they stimulate both antibody-secreting cells (B cells) and cytotoxic T cells during an immune response, unlike the other cell types listed.