Cohn M, Langman R E
The Salk Institute, P.O. Box 85800, San Diego, California 92186-5800, USA.
Front Biosci. 1996 Oct 1;1:d318-23. doi: 10.2741/a134.
The self-nonself discrimination is germline encoded for defense mechanisms, but it is somatically learned for the immune system and this is the fundamental difference between the two. When referring to the defense mechanisms of vertebrates, immunologists like to use the term "innate immune systems" to describe the germline encoded class of defense mechanism. It was the acquisition of a somatically learned S-NS discrimination during vertebrate evolution that permitted the immune system to develop large recognitive repertoires compared to those of defense mechanisms. This seemingly boundless immune repertoire has fascinated immunologists for almost a century. Today we have a better understanding of the size and function of the antibody repertoire. Humoral antibody effector functions depend upon secreted immunoglobulin and the concentration of antibody must reach a minimum effective threshold in a short enough time to stop a growing pathogen before it becomes lethal. This requires that initially an equivalent number of B-cells per ml respond to the pathogen. This number of B-cells must respond for each and every milliliter of animal. Consequently, the humoral immune system must be iterated. This straightforward conclusion has far reaching implications, some of which are explored in this review.
自我与非自我的区分在防御机制中是由种系编码的，但在免疫系统中是体细胞习得的，这是两者之间的根本区别。当提及脊椎动物的防御机制时，免疫学家喜欢用“先天免疫系统”这个术语来描述由种系编码的防御机制类别。在脊椎动物进化过程中获得的体细胞习得的自我-非自我区分，使得免疫系统能够发展出与防御机制相比更大的识别库。这种看似无限的免疫库已经吸引免疫学家近一个世纪了。如今，我们对抗体库的大小和功能有了更好的理解。体液抗体效应功能依赖于分泌的免疫球蛋白，并且抗体浓度必须在足够短的时间内达到最低有效阈值，以便在病原体变得致命之前阻止其生长。这要求每毫升最初有等量的B细胞对病原体作出反应。每毫升动物体内都必须有这个数量的B细胞作出反应。因此，体液免疫系统必须反复运作。这个简单直接的结论有着深远的影响，本文将探讨其中的一些影响。
