section_path: Adaptive immune system/Antigen presentation to T lymphocytes
section_name: Antigen presentation to T lymphocytes
paragraph_text: Antigen presentation to T lymphocytes
  
  Both B cells and T cells carry receptor molecules that recognize specific targets. T cells recognize a "non-self" target, such as a pathogen, only after antigens (small fragments of the pathogen) have been processed and presented in combination with a "self" receptor called a major histocompatibility complex (MHC) molecule.