T-cell receptor repertoire and function in umbilical cord blood lymphocytes from newborns of type 1 diabetic mothers

Abstract Recent observations show that the development of the human fetal immune system is susceptible to conditions of the maternal immune system and vice versa. To investigate the impact of type 1 diabetes mellitus in pregnant women on the maturation of the immune system of their newborn infants, the umbilical cord blood (UCB) T-cell repertoire at birth was analysed for clonal or oligoclonal expansions and TCRBV gene usage. Quantitative PCR using TCRBV family-specific probes and the spectratyping method were used. The extent of oligoclonal expansions observed in cord blood was markedly lower than in peripheral blood of the diabetic mothers and healthy adults. Functional analysis revealed that UCB T cells from newborns of both type 1 diabetic and gestational diabetic mothers are mature and can be readily stimulated by superantigens and phytohemagglutinin in vitro. No significant differences of the clonal contingent and the TCRBV usage were found in newborns of type 1 diabetic mothers when compared to newborns of gestational diabetic mothers, independent from the presence or absence of islet autoantigens. Our findings indicate that the immune system of type 1 diabetic mothers has no major effects on the TCR repertoire of the newborn infants. In that respect, no evidence was found for superantigen-activated T cells, nor was chronic hyperglycaemia per se found to alter either T-cell repertoire or functional activity.     

Cellular Aspects of Atopic Dermatitis

Atopic dermatitis (AD) is a highly pruritic, chronic, and relapsing inflammatory skin disease. Recent interest in AD has been sparked by reports of its increasing prevalence and its contribution to increasing health care costs. A precise understanding of immunologic mechanisms is crucial for the development of effective treatment strategies for AD. Various studies reveal that AD has a multifactorial cause with the activation of complex immunologic and inflammatory pathways. This review will discuss cellular-mediated immunological pathomechanisms of AD. Emphasis will be given to the role played by T cells, antigen-presenting cells, eosinophils, and keratinocytes. We also examine the immunological effect of superantigens on various inflammatory cells including T regulatory cells.     

超抗原金黄色葡萄球菌肠毒素B亚单位防治大鼠高危角膜移植免疫排斥反应的研究

目的探讨超抗原金黄色葡萄球菌肠毒素B亚单位(SEB)对大鼠高危角膜移植免疫排斥反应的防治作用机制。方法实验供体为30只Fisher344和4只Lewis大鼠,受体为64只Lewis大鼠。将实验受体大鼠按随机数字表法随机分为4个治疗组和1个对照组,每组12只;同时设4只Lewis大鼠行同种同体移植。治疗组术前分别用02ml不同浓度的SEB(25、50、75、100μg/kg)腹腔注射诱导免疫耐受。对照组用02ml生理盐水腹腔注射。缝线法诱导受体角膜新生血管,然后行穿透性角膜移植术,术后观察记录植片的存活状况并对受体全身免疫状态进行免疫组化染色,流式细胞分析和淋巴细胞增殖能力检测。结果对照组大鼠角膜植片的平均存活时间为(730±067)d,SEB治疗组(25、50、75、100μg/kg)植片存活时间分别为(643±127)d、(1070±250)d、(1250±141)d、(883±194)d。免疫组织化学染色和流式细胞检测显示SEB治疗组大鼠角膜植片中淋巴细胞的浸润以及外周免疫器官中淋巴细胞亚群百分数较对照组明显降低。此外,SEB治疗组中受体淋巴细胞对供体抗原刺激的反应性降低,外周血中白细胞介素(IL)2浓度降低而IL10浓度升高,其中以SEB75μg/kg组作用最明显。结论在一定剂量范围内,SEB可以诱导大鼠免疫耐受形成,减少局部和全身淋巴细胞数量,并有效防治高危角膜移植免     

Role of staphylococcal superantigen in atopic dermatitis: influence on keratinocytes

Staphylococcus aureus may perform an crucial function in atopic dermatitis (AD), via the secretion of superantigens, including staphylococcal enterotoxins (SE) A or B, and toxic shock syndrome toxin-1 (TSST-1). Dysregulated cytokine production by keratinocytes (KCs) upon exposure to staphylococcal superantigens (SsAgs) may be principally involved in the pathophysiology of AD. We hypothesized that lesional KCs from AD may react differently to SsAgs compared to nonlesional skin or normal skin from nonatopics. We conducted a comparison of HLA-DR or CD1a expression in lesional skin as opposed to that in nonlesional or normal skin by immunohistochemistry (IHC). We also compared, using ELISA, the levels of IL-1alpha, IL-1beta, and TNF-alpha secreted by cultured KCs from lesional, nonlesional, and normal skin, after the addition of SEA, SEB and TSST-1. IHC revealed that both HLA-DR and CD1a expression increased significantly in the epidermis of lesional skin versus nonlesional or normal skin in quite a similar manner. IL-1alpha, IL-1beta, and TNF-alpha secretion was also significantly elevated in the cultured KCs from lesional skin after the addition of SsAgs. Our results indicated that KCs from lesional skin appear to react differently to SsAgs and increased proinflammatory cytokine production in response to SsAgs may contribute to the pathogenesis of AD.     

Superantigens: Biology,immunology, and potential role in disease

Superantigens are unique products of bacteria and viruses which, in combination with class II major histocompatibility complex molecules, are capable of stimulating a large fraction of T cells in an affected individual. This stimulation primarily involves the variable region of the T cell receptor beta chain (V). The discovery of superantigens and the elucidation of their immunologic properties have provided valuable tools for the investigation of the immune system in both normal and diseased animals. Most importantly, recent work suggests that superantigens play a role in a number of diverse pathological conditions, including toxic shock syndrome and autoimmune diseases such as rheumatoid arthritis.     

Analysis of the IGHV region in Burkitt's lymphomas supports a germinal center origin and a role for superantigens in lymphomagenesis

The analysis of immunoglobulin heavy chain variable (IGHV) region may disclose the influence of antigens in Burkitt's lymphomas (BL). IGHV sequences from 38 patients and 35 cell lines were analyzed. IGHV3 subset genes were the most used and IGHV4-34 gene was overrepresented. IGHV genes were mutated in 98.6% of the cases, 36% acquired potential glycosylation sites, and in 52% somatic-hypermutation-process was ongoing. Binding motifs for superantigens like Staphylococcal protein A and carbohydrate I/i were preserved in 89% of the cases. IGHV analysis of BL cells supports a germinal center origin and points toward a role for superantigens in lymphomagenesis.     

金黄色葡萄球菌性超抗原诱发银屑病发病机理探讨

目的探讨金黄色葡萄球菌性超抗原诱发银屑病的机制。方法3H-TdR掺入法测定细胞增殖反应,亚二倍体细胞含量测定,片段化DNA分析,膜联蛋白V(AnnexinV)法测定细胞凋亡,流式细胞仪检测细胞表面抗原表达。结果金黄色葡萄球菌肠毒素B活化的淋巴细胞培养上清液作用于角质形成细胞48h,可促进角质形成细胞增殖,诱导角质形成细胞表达HLA-DR和Fas抗原;再次加入上清液继续作用48h,则诱导角质形成细胞凋亡（P<0.01）。结论金黄色葡萄球菌肠毒素B作为超抗原活化T细胞,使之释放细胞因子,后者使角质形成细胞首先活化增殖,继而凋亡。     

特应性皮炎患儿皮损局部金黄色葡萄球菌外毒素检测

目的 了解特应性皮炎(AD)患儿皮损局部金黄色葡萄球菌(金葡菌)的带菌率及其分泌外毒素的情况,探讨金葡菌及其分泌的外毒素在AD发病中的作用.方法 AD皮损局部分离金葡菌,反向被动乳胶试验方法检测其外毒素表达,并与对照组进行统计学比较.结果 与对照组相比,AD患儿无论是皮损局部还是非皮损区金葡菌带菌率明显升高(P值均<0.01),且与疾病严重性呈正相关性(P<0.01).但AD皮损局部的金葡菌与对照组金葡菌相比,两者分泌外毒素的情况差异无显著性(P>0.05),并且皮损局部的金葡菌是否分泌外毒素与疾病严重性无直接相关性(P>0.05),但伴有血清总IgE水平升高的AD患儿,疾病相对较重(P<0.01).结论 AD患儿皮损区金葡菌带菌率为43.24%,其中47.46%分泌外毒素,以金葡菌肠毒素B(SEB)最常见.     

The Presence of Superantigens and Complex Host Responses in Severe Sepsis May Need a Broad Therapeutic Approach

Abstract: Patients with sepsis can progress into septic shock, disseminated intravascular coagulation, and multiorgan dysfunction syndrome. Various materials secreted by or released from microorganisms such as bacteria initiate these processes. In some bacteria, certain antigens and toxins may cause a 100‐fold greater or supernormal activation of monocytes and T lymphocytes, leading to activation of the cascade systems in the host. This can explain the extremely rapid progress of the sepsis into septic shock seen in some patients. In Group A streptococci, more than 100 different toxins have been identified, about 5 of which (superantigens) cause an extremely fast immunological response. Because the toxins and antigens can activate so many different cascade systems in the host, the clinical picture is extremely complex, and little benefit is derived from therapy, which interferes with only 1 or 2 of the parameters in the patient with sepsis. Instead, reversal of the septic shock requires the removal or inhibition of several toxins or substances activating the cascade systems. A broader therapeutic approach may be the use of apheresis (plasma exchange).