Interaction with an antigen-presenting cell is required for T cell:

• A. phagocytosis
• B. complement fixation
• C. activation
• D. antibody production

Answer: (C)

Verified step by step guidance

1. Understand the role of T cells in the immune response: T cells are a type of lymphocyte that play a central role in cell-mediated immunity.
2. Recognize that antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells process and present antigens on their surface using MHC molecules.
3. Know that T cells require interaction with these antigen-MHC complexes on APCs to become activated; this interaction is crucial for initiating the T cell response.
4. Recall that phagocytosis is primarily performed by macrophages and neutrophils, not T cells, and complement fixation is part of the innate immune system, not directly related to T cell activation.
5. Understand that antibody production is mainly the function of B cells, which can be helped by activated T helper cells, but the direct interaction with APCs is specifically required for T cell activation.