ABSTRACT
The innate immune system contains cells and mechanisms that defend or ght against infection by other microorganisms in a generalized manner, which suggests that the cells of the innate system identify and respond to pathogens in a common way, and it does not
convene long-lasting or protective immunity to the host (Figure 5.1). It has been reported that innate immune systems offer immediate defense against infection and are found in all plants and animals. It has been found that the innate immune system generally consists of three components-membrane barrier, inammation, and complement system-to protect the cells from infections. In case a pathogen breaks these barriers, the innate immune system provides an immediate response to control pathogen entry. In case pathogens can successfully evade the innate response, a host body possesses another layer of protection called the adaptive immune system, which can be activated by the innate response. At this point, the immune system familiarizes its response during an infection to increase its recognition of the pathogen. This enhanced response against pathogens is then remembered in the form of an immunological memory after the pathogen has been removed, and allows the adaptive immune system to withstand faster and stronger attacks each time this pathogen is detected (Figures 5.2 and 5.3).
