Berczi I, Bertók L, Chow D A
Department of Immunology, Faculty of Medicine, University of Manitoba, 795 McDermot Avenue, Winnipeg, Manitoba, R3E 0W3, Canada.
Ann N Y Acad Sci. 2000;917:248-57. doi: 10.1111/j.1749-6632.2000.tb05390.x.
Innate resistance is mediated by non-immune defense and by natural immunity. Non-immune defense includes diverse mechanisms (e.g., physico-chemical defense by bile acids). Natural killer (NK) cells, gamma delta T lymphocytes and CD5+ B lymphocytes are key mediators of natural immunity. These cells utilize germ-line coded receptors that recognize highly conserved, homologous epitopes (homotopes). Typically, it is not the antigen, but cytokines and hormones that regulate the level of NK-mediated cytotoxicity. These include interleukin-2, interferons, prolactin and growth hormone. Less is known about gamma delta T lymphocytes. CD5+ B lymphocytes produce germ-line coded antibodies (predominantly IgM) that are polyspecific, and able to recognize a great variety of microorganisms, cancer-cells and self-components. Antigen is not an effective stimulus for natural antibody (NAb), but bacterial lipopolysaccharide (LPS) is. During the acute phase response (febrile illness) the T-cell-regulated adaptive immune response is switched off and natural immune mechanisms are amplified several hundred to a thousand times within 24-48 hours (immunoconversion). This immunoconversion is initiated by immune-derived cytokines, and involves profound neuroendocrine and metabolic changes, all in the interest of host defense. Immune recognition is assured by natural antibodies and by some liver-derived acute phase proteins, such as C-reactive protein or endotoxin-binding protein, the level of which is elevated in the serum. Thus, natural immunity is essential for a first and last line of defense and the neuroendocrine system is an important promoter of this activity.
固有抗性由非免疫防御和天然免疫介导。非免疫防御包括多种机制（例如，胆汁酸的物理化学防御）。自然杀伤（NK）细胞、γδT淋巴细胞和CD5+B淋巴细胞是天然免疫的关键介质。这些细胞利用种系编码的受体来识别高度保守的同源表位（同源位）。通常，调节NK介导的细胞毒性水平的不是抗原，而是细胞因子和激素。这些包括白细胞介素-2、干扰素、催乳素和生长激素。关于γδT淋巴细胞的了解较少。CD5+B淋巴细胞产生种系编码的抗体（主要是IgM），这些抗体具有多特异性，能够识别多种微生物、癌细胞和自身成分。抗原不是天然抗体（NAb）的有效刺激物，但细菌脂多糖（LPS）是。在急性期反应（发热性疾病）期间，T细胞调节的适应性免疫反应被关闭，天然免疫机制在24-48小时内放大数百至一千倍（免疫转换）。这种免疫转换由免疫衍生的细胞因子启动，涉及深刻的神经内分泌和代谢变化，所有这些都是为了宿主防御。天然抗体和一些肝脏衍生的急性期蛋白（如C反应蛋白或内毒素结合蛋白）可确保免疫识别，其血清水平会升高。因此，天然免疫对于第一道和最后一道防线至关重要，神经内分泌系统是这种活动的重要促进者。
