Lopez-Romero Gloria, Garzon Thania, Rascon Raul, Valdez Alejandra, Quintero Jael, Arvizu-Flores Aldo A, Garibay-Escobar Adriana, Rascon Lucila, Astiazarán-García Humberto, Velazquez Carlos
Coordinación de Nutrición, Centro de Investigación en Alimentación y Desarrollo A.C. Hermosillo, Sonora, Mexico.
Department of Chemistry-Biology, University of Sonora, Hermosillo, Sonora, Mexico.
Immunobiology. 2017 Aug;222(8-9):884-891. doi: 10.1016/j.imbio.2017.05.008. Epub 2017 May 17.
Giardia lamblia is a protozoan parasite that causes one of the most common gastrointestinal diseases worldwide. To eliminate the parasite from the host intestine, it is necessary the activation of B-cell and T-cell dependent mechanisms. The knowledge about Giardia antigens that can stimulate the host immune response is limited. Recently, it has been described the Binding Immunoglobulin Protein (BIP) of G. lamblia (71kDa) as a potential immunogen. Additionally, our group has identified a highly immunogenic antigen (5G8 protein) of G. lamblia with a relative molecular mass of approximately 70kDa. There is some evidence suggesting that the 5G8 protein may activate both humoral and cellular immune responses. Based on these observations and preliminary mass spectrometry analyses, we hypothesized that the antigen 5G8 could be the BIP protein. In the present study, we characterize immunochemically the BIP protein of Giardia. Flow cytometric assays and western blotting were used to determine the expression profile of BIP and 5G8 antigens in Giardia trophozoites. The differences in expression profile indicated that BIP and 5G8 are not the same molecule. ELISA and Western blotting assays revealed that BIP protein was recognized by antibodies produced during G. lamblia infection in C3H/HeN mice. MTT assays did not reveal the activation of cellular immune response induced by BIP protein in vitro. In addition, we identified the potential B-cell and T-cell epitopes of G. lamblia BIP protein. This molecule is a conserved protein among Giardia strains and other pathogens. The complete immunological characterization of this antigen will contribute to a better understanding of the host-parasite interactions in Giardia infection.
蓝氏贾第鞭毛虫是一种原生动物寄生虫，可引发全球最常见的胃肠道疾病之一。要从宿主肠道中清除该寄生虫，激活B细胞和T细胞依赖性机制是必要的。关于能刺激宿主免疫反应的蓝氏贾第鞭毛虫抗原的知识有限。最近，已将蓝氏贾第鞭毛虫的结合免疫球蛋白蛋白（BIP，71kDa）描述为一种潜在的免疫原。此外，我们团队已鉴定出蓝氏贾第鞭毛虫一种相对分子质量约为70kDa的高免疫原性抗原（5G8蛋白）。有一些证据表明5G8蛋白可能激活体液免疫和细胞免疫反应。基于这些观察结果和初步的质谱分析，我们推测抗原5G8可能就是BIP蛋白。在本研究中，我们对蓝氏贾第鞭毛虫的BIP蛋白进行了免疫化学特征分析。采用流式细胞术检测和蛋白质印迹法来确定BIP和5G8抗原在蓝氏贾第鞭毛虫滋养体中的表达谱。表达谱的差异表明BIP和5G8不是同一分子。酶联免疫吸附测定（ELISA）和蛋白质印迹分析显示，BIP蛋白可被C3H/HeN小鼠感染蓝氏贾第鞭毛虫期间产生的抗体识别。MTT检测未揭示BIP蛋白在体外诱导的细胞免疫反应的激活。此外，我们鉴定了蓝氏贾第鞭毛虫BIP蛋白潜在的B细胞和T细胞表位。该分子在蓝氏贾第鞭毛虫菌株和其他病原体中是一种保守蛋白。对该抗原进行完整的免疫学特征分析将有助于更好地理解蓝氏贾第鞭毛虫感染中的宿主 - 寄生虫相互作用。
