Which cell type is solely responsible for activating T cells?

Dendritic cells are the cell type solely responsible for activating T cells due to their unique role in the immune response. They are specialized antigen-presenting cells that can process and present antigens to T cells, particularly naïve T cells, in a way that is crucial for initiating adaptive immunity. Upon encountering pathogens, dendritic cells capture and internalize antigens through various mechanisms. They then migrate to the lymph nodes, where they present processed peptides on major histocompatibility complex (MHC) molecules to T cell receptors (TCRs) on T cells.

This interaction is essential for T cell activation because it not only delivers the necessary signals for T cell maturation but also ensures that T cells are educated to recognize specific antigens associated with pathogens. Additionally, dendritic cells produce various cytokines that enhance T cell activation and proliferation, thus playing a pivotal role in orchestrating an adaptive immune response.

In contrast, although B cells and macrophages can also present antigens and participate in T cell activation, they do not exclusively function in activating naïve T cells like dendritic cells do. Natural killer (NK) cells, on the other hand, primarily contribute to the innate immune response and do not activate T cells directly. Thus, dendritic