Components of the first line of defense include all the following except?

The components of the first line of defense include physical barriers such as skin and mucous membranes, as well as chemical barriers like enzymes and antimicrobial peptides. However, the adaptive immune response, which involves specific immune cells and antibodies, is not part of the first line of defense; it is considered the third line of defense. Therefore, any reference to adaptive immune components would be the exception in this context.