Division of Immunology, Children's Hospital Boston, Boston, MA 02115, USA.
J Allergy Clin Immunol. 2010 Feb;125(2 Suppl 2):S33-40. doi: 10.1016/j.jaci.2009.09.017. Epub 2010 Jan 12.
The innate immune system provides critical mechanisms for the rapid sensing and elimination of pathogens. Adaptive immunity has evolved to provide a broader and more finely tuned repertoire of recognition for both self- and nonself-antigens. Adaptive immunity involves a tightly regulated interplay between antigen-presenting cells and T and B lymphocytes, which facilitate pathogen-specific immunologic effector pathways, generation of immunologic memory, and regulation of host immune homeostasis. Lymphocytes develop and are activated within a series of lymphoid organs comprising the lymphatic system. During development, sets of gene segments are rearranged and assembled to create genes encoding the specific antigen receptors of T and B lymphocytes. The rearrangement mechanism generates a tremendously diverse repertoire of receptor specificities capable of recognizing components of all potential pathogens. In addition to specificity, another principal feature of adaptive immunity is the generation of immunologic memory. During the first encounter with an antigen (pathogen), sets of long-lived memory T and B cells are established. In subsequent encounters with the same pathogen, the memory cells are quickly activated to yield a more rapid and robust protective response.
先天免疫系统为快速感知和消除病原体提供了关键机制。适应性免疫系统的进化提供了更广泛和更精细的自我和非自我抗原识别 repertoire。适应性免疫涉及抗原呈递细胞和 T 和 B 淋巴细胞之间的紧密调节相互作用，促进病原体特异性免疫效应途径、免疫记忆的产生和宿主免疫稳态的调节。淋巴细胞在一系列淋巴器官中发育和激活，这些器官构成了淋巴系统。在发育过程中，基因片段的集合被重新排列和组装，以创建编码 T 和 B 淋巴细胞特异性抗原受体的基因。重排机制产生了大量多样化的受体特异性，能够识别所有潜在病原体的成分。除了特异性之外，适应性免疫的另一个主要特征是产生免疫记忆。在第一次接触抗原（病原体）时，会建立一组长寿的记忆 T 和 B 细胞。在随后与同一病原体的接触中，记忆细胞会迅速被激活，产生更快速和更强有力的保护反应。
