A pathogen that succeeds in breaking into the tissues and organs of a host represents a threat in response to which the immune system has developed. The body's first response when challenged by an infection is generic; the innate immune response is mainly expressed as inflammation resulting from the activation of receptors that recognise molecular motives specific to germs and more generally molecules that the host produces when threatened. The immune response is also adaptive, that is to say the immune system is capable of providing a response that is specific to the antigens produced by each pathogen, ensuring that the infectious agent that initiated the innate response is completely eradicated and protecting the host against any subsequent infection by the same agent. The orientation and efficacy of the body's adaptive immune response depend on the quality and intensity of the innate immune response