Prevalence and immunogenicity of HNA-3a and -3b antibodies and antigens

描述（由申请人提供）：输血相关急性肺损伤（TRALI）是目前输血相关死亡的主要原因，是由向易感患者输注含有白细胞抗体和/或生物反应调节剂的血液制品引发的。尽管许多不同的白细胞抗体已被证明可诱导TRALI，但那些针对白细胞抗原HNA-3a的抗体特别容易引起非常严重的，往往是致命的反应。不幸的是，对献血者进行常规筛查一直是不可能的，因为它的分子特性多年来一直困扰着研究人员，而且因为HNA-3a被认为是中性粒细胞特异性的，一种难以用于血清学研究的细胞。因此，我们对抗hla -3a在献血者中的流行程度知之甚少，对该抗原的免疫原性也知之甚少。尽管从理论上讲，它们与抗HNA-3a一样可能引起TRALI，但人们对识别HNA-3b （HNA-3a的等位基因）的抗体知之甚少。我们最近发现，胆碱转运蛋白样蛋白2 （CTL2）携带了HNA-3a，并且几乎可以肯定，HNA-3a/b多态性是由10-跨膜CTL2蛋白的第一个胞外环的R>Q154 （R=HNA-3a, Q = HNA-3b）氨基酸取代决定的。这些发现提示了开发一种适用于常规供体筛选的抗- hna -3a和抗-3b检测方法的方法。在这个应用中，我们提议产生重组和合成含有R154和Q154的CTL2和CTL2片段，并表征它们对一组hna -3特异性抗体的反应。被发现对抗ctl2检测最敏感和特异性的构建体将大量生产，形成原型固相免疫测定，并用于筛选输注、非输注和分娩的男性和女性的7000份血清样本，以确定这些人群中抗hna -3a的患病率。这些构建体的Q154版本应该提供抗hna -3b的可比信息。研究结果有望1)首次确定献血人群中抗rna -3a和抗rna -3b的患病率；2)表征HNA-3和HNA-3b的免疫原性（通过输血或怀孕期间暴露于抗原诱导抗体的可能性），3)为确定是否有必要对献血者进行常规筛查抗hna -3a和抗HNA-3b建立基础。

DESCRIPTION (provided by applicant): Transfusion-associated acute lung injury (TRALI), currently the leading cause of transfusion- associated fatality, is triggered by transfusion of blood products containing leukocyte antibodies and/or biological response modifiers to susceptible patients. Although many different leukocyte antibodies have been shown to induce TRALI, those specific for the leukocyte antigen HNA-3a are especially prone to cause very severe, and often fatal reactions. Unfortunately, it has not been possible to screen blood donors routinely for anti-HNA-3a because its molecular properties have for many years eluded investigators and because HNA-3a was thought to be neutrophil-specific, a cell difficult to use in serologic studies. Thus, very little is known about the prevalence of anti-HNA-3a in blood donors and the immunogenicity of this antigen is poorly understood. Even less is known about antibodies that recognize HNA-3b, the allele of HNA-3a, although they should, in theory, be as likely to cause TRALI as anti-HNA-3a. We recently showed that HNA-3a is carried on choline transporter- like protein 2 (CTL2) and that the HNA-3a/b polymorphism is almost certainly determined by an R>Q154 (R=HNA-3a, Q = HNA-3b) amino acid substitution in the first extracellular loop of the 10- membrane-spanning CTL2 protein. These findings suggest ways to develop a practical assay for detection of anti-HNA-3a and anti-3b suitable for routine donor screening. In this application, we propose to generate recombinant and synthetic CTL2 and CTL2 fragments containing R154 and Q154 and characterize their reactions against a panel of HNA-3-specific antibodies. Constructs found to be most sensitive and specific for anti-CTL2 detection will be produced in quantity, formatted into a prototype solid phase immunoassay, and used to screen 7,000 serum samples from transfused, non-transfused and parous males and females to determine the prevalence of anti-HNA-3a in these populations. The Q154 version of these constructs should provide comparable information about anti-HNA-3b. Findings made are expected to 1) define, for the first time, the prevalence of anti-HNA-3a and anti- HNA-3b in blood donor populations; 2) characterize the immunogenicity of HNA-3 and HNA-3b (likelihood of an antibody being induced upon exposure to antigen through transfusion or during pregnancy) and 3) establish a basis for determining whether routine screening of blood donors for anti-HNA-3a and anti-HNA-3b is warranted. PUBLIC HEALTH RELEVANCE: Transfusion-associated acute lung injury (TRALI) is a serious complication of blood transfusion and the most common cause of transfusion-related mortality. Transfusion of antibodies specific for white blood cells (leukocytes) is a major cause of TRALI. Antibodies against a leukocyte antigen designated HNA-3a are especially prone to cause severe, often fatal TRALI but, for technical reasons, it has not been possible to test blood donors to detect them. Recent findings made in our laboratory make it likely that this obstacle can be overcome and studies to accomplish this are described in this application.))