Interleukin-4 is a signature cytokine of T-helper type 2 (Th2) cells that play a major role in shaping immune responses. Its role in highly relevant animal model of tuberculosis (TB) like guinea pig has not been studied till date. In the current study, the guinea pig IL-4 gene was cloned and expressed using a prokaryotic expression vector (pET30 a(+)). This approach yielded a recombinant protein of 19 kDa as confirmed by mass spectrometry analysis and named as recombinant guinea pig (rgp)IL-4 protein. The authenticity of the expression of rgpIL-4 protein was further verified through polyclonal anti-IL4 antiserum raised in rabbits that showed specific and strong binding with the recombinant protein. The biological activity of the rgpIL-4 was ascertained in RAW264.7 cells where LPS-treated nitric oxide (NO) production was found to be suppressed in the presence of this protein. The three-dimensional structure of guinea pig IL-4 was predicted by utilizing the template structure of human interleukin-4, which shared a sequence homology of 58%. The homology modeling result showed clear resemblance of guinea pig IL-4 structure with the human IL-4. Taken together, our study indicates that the newly expressed, biologically active rgpIL-4 protein could provide deeper understanding of the immune responses in guinea pig to different infectious diseases like TB and non-infectious ones.

中文翻译：

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豚鼠IL-4的原核表达，体外生物学分析和计算机模拟结构评估。

白介素-4是2型T辅助细胞（Th2）的标志性细胞因子，在塑造免疫应答中起主要作用。迄今为止，尚未研究其在与豚鼠等结核病（TB）高度相关的动物模型中的作用。在当前的研究中，使用原核表达载体（pET30 a（+））克隆并表达了豚鼠IL-4基因。经质谱分析证实，该方法产生了19 kDa的重组蛋白，并命名为重组豚鼠（rgp）IL-4蛋白。rgpIL-4蛋白表达的真实性通过在兔中产生的多克隆抗IL4抗血清进一步证实，该抗血清显示出与重组蛋白的特异性和强结合性。rgpIL-4的生物学活性在RAW264中确定。发现在这种蛋白质存在下，经LPS处理的一氧化氮（NO）产生受到抑制的7个细胞。利用人白细胞介素4的模板结构预测了豚鼠IL-4的三维结构，该模板结构具有58％的序列同源性。同源性建模结果显示豚鼠IL-4结构与人IL-4明显相似。综上所述，我们的研究表明，新近表达的具有生物活性的rgpIL-4蛋白可以提供对豚鼠对结核病和非传染性疾病等多种传染性疾病的免疫反应的更深入了解。同源性建模结果显示豚鼠IL-4结构与人IL-4明显相似。综上所述，我们的研究表明，新近表达的具有生物活性的rgpIL-4蛋白可以提供对豚鼠对结核病和非传染性疾病等多种传染性疾病的免疫反应的更深入了解。同源性建模结果显示豚鼠IL-4结构与人IL-4明显相似。综上所述，我们的研究表明，新近表达的具有生物活性的rgpIL-4蛋白可以提供对豚鼠对结核病和非传染性疾病等多种传染性疾病的免疫反应的更深入了解。