Final answer:
It is false that T cells recognize native protein antigens; they recognize processed antigens presented alongside MHC molecules. B cells can recognize unprocessed antigens directly without needing MHC. T cells are activated upon recognizing the antigen-MHC complex on antigen-presenting cells.
Step-by-step explanation:
The statement that T cells recognize native protein antigens is false. T cells do not interact with unprocessed antigens in the same way that B cells do. Instead, T cells recognize antigens that have been processed and presented on the surface of cells by Major Histocompatibility Complex (MHC) molecules.
B cells, on the other hand, can recognize and bind to native, unprocessed antigens directly. They do not necessarily need MHC molecules to assist in antigen recognition. T cells require the presentation of antigen in the context of MHC molecules. This process is crucial for T cell activation and the subsequent immune response.
When an antigen enters the body, it is typically processed by antigen-presenting cells (APCs) before being displayed on MHC molecules. The T cells then use their antigen receptor to recognize and bind to this antigen-MHC complex. Once a match is found, as if a key fits a lock, the T cell is activated and can perform its immune functions, which may include killing infected cells or helping to activate other immune cells.