Toll-Like Receptor Familiy Members and Their Ligands

The innate immune system is sometimes referred to as the "primitive" immune system. Perhaps this has dissuaded immunologists from analyzing it so energetically as they have analyzed the adaptive immune system during the past two decades. But while its phylogenetic origins are indeed ancient, and though it is "of the first type," there is nothing crude, nothing unsophisticated, and nothing "inferior" about innate immunity. On the contrary, the innate immune system has had time to achieve a level of refinement that is nothing short of dazzling, and a modicum of respect is at long last due.