Fig. (1).

Differentiation of the adaptive immune response. 1 An antigen presenting cell ingests and processes the foreign agent (grey dot) with the consequent antigen presentation of fragments thereof in membrane receptors; 2 Subsequently, a process called selection occurs where a lymphocyte capable of recognizing the antigen will be selected and; 3 finally, clonal expansion occurs in which the size of the original clone increases, so that it is possible for the adaptive immune response to develop a specific humoral response that consists of the production of specific antibodies against the antigen. (A higher resolution/colour version of this figure is available in the electronic copy of the article).