The specific defense is acquired after exposure to a certain pathogen, hence it’s named adaptive immunity. The specific defense or adaptive immunity responds to specific pathogen. The pathogen can be recognised through MAMPs - microbial-associated molecular patterns. MAMPs are set of molecular patterns that are general components of both pathogenic and nonpathogenic microorganisms, which are recognised by TLRs (toll like receptors) expressed by many types of immunological cells, including macrophages, dendritic cells, B cells, stromal cells, and certain epithelial cells.

Immunological memory is also a notable characteristic of adaptive immunity. B cell and T cells are the primary effector cells of the adaptive immune response. Macrophages and dendritic cells can play a response initiating role as antigen presenters.

T cells mature in the thymus. These cells have many roles in the immune repertoire including killing whole cells that are infected by pathogens, activating or stimulating other immune cells, and destroying body cells that no longer bear the markers of a normal self cell. B cells mature in the bone marrow, and produce antibodies.

Adaptive immunity can be divided into two categories: humoral immunity and cell-mediated immunity.

Humoral immunity involves production of antibodies that circulate in the bloodstream and lymph. Cell-mediated immunity is conferred by T cell responses and does not involve antibodies.