Step 1: Concept
Professional Antigen Presenting Cells (pAPCs) are specialized cells that capture antigens and present them to T-cells to initiate an adaptive immune response.
Step 2: Meaning
While many cells can present antigens, "professional" cells express MHC Class II and costimulatory molecules required for T-cell activation.
Step 3: Analysis
The three main types of pAPCs are Dendritic cells, Macrophages, and B-cells. Dendritic cells are considered the most potent because they are the primary cells responsible for activating naive T-cells. Fibroblasts and epithelial cells are non-professional.
Step 4: Conclusion
Dendritic cells are the definitive pAPCs among the choices provided.
Final Answer: (C)
