Changes in the innate and adaptive immune system have been observed.

Phagocytes form part of the innate immune system, which animals, including humans, are born with.

With that hypothesis confirmed, the researchers turned to the question of how the innate immune system actually kept the bacteria away.

Other genes of the innate immune system also seem to be subject to powerful positive selection.

Natural killer cell, a cell involved in the innate immune system.

The simplest innate system is the cell wall or barrier on the outside to stop intruders getting in.

The innate system is the evolutionarily older defense strategy.

The body's first line of defence against viruses is the innate immune system.

The cells of the innate system recognise, and respond to, pathogens in a general way.

They act as messengers between the innate and adaptive immune systems.