Nutrition Program, School of Biological and Population Health Sciences, College of Public Health and Human Sciences, Oregon State University, Corvallis, OR 97331, USA.
Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA.
Nutrients. 2020 Jun 27;12(7):1904. doi: 10.3390/nu12071904.
Oral administration of pathogen-specific recombinant antibodies may help to prevent infant gastrointestinal (GI) pathogen infection; however, to neutralize an infectious agent, these antibodies must resist degradation in the GI tract. Palivizumab, a recombinant antibody specific for the respiratory syncytial virus (RSV), was used as a model for pathogen-specific IgG in human milk. The aim was to compare the remaining binding capacity of palivizumab in milk between three mothers after exposure to an in vitro model of infant gastrointestinal digestion (gastric and duodenal fluids) using ELISA. The neutralizing capacity of palivizumab in pooled human milk, gastric contents, and stools from preterm infants was also evaluated for blocking RSV with green fluorescent protein (RSV-GFP) infection in Hep-2 cells using confocal and inverted microscopy and flow cytometry. The reduction of palivizumab binding capacity in human milk and digested samples was slightly different between mothers. Overall, palivizumab decreased 50% after simulated gastric digestion with pepsin and 62% after simulated intestinal digestion with pancreatin. Palivizumab (2-8 μg/mL) in human milk or stool samples blocked RSV (3.4 × 10 FFU/mL) infection (no syncytia formation on Hep-2 cells) by microscopy. Syncytia formation was detected on Hep-2 cells when RSV was incubated in gastric contents or virus medium with 2-4 μg/mL of palivizumab, but no infection was observed at 8 μg/mL. No fluorescence (absence of infected cells) was detected when palivizumab (100 μg/mL) was incubated in human milk or medium with RSV-GFP (1.1 × 10 FFU/mL), whereas fluorescence increased with the reduced concentration of palivizumab using flow cytometry. These results suggest that undigested and digested matrices could change the binding and neutralizing capacity of viral pathogen-specific antibodies.
口服病原体特异性重组抗体可能有助于预防婴儿胃肠道 (GI) 病原体感染；然而，为了中和感染因子，这些抗体必须在胃肠道中抵抗降解。帕利珠单抗是一种针对呼吸道合胞病毒 (RSV) 的重组抗体，被用作人乳中病原体特异性 IgG 的模型。本研究旨在使用 ELISA 比较 3 位母亲在体外婴儿胃肠道消化模型（胃和十二指肠液）暴露后，帕利珠单抗在人乳中的结合能力。还评估了帕利珠单抗在早产儿人乳、胃液和粪便中的中和能力，以使用共聚焦和倒置显微镜以及流式细胞术阻断绿色荧光蛋白 (RSV-GFP) 感染 Hep-2 细胞。在人乳和消化样本中，帕利珠单抗的结合能力减少在母亲之间略有不同。总体而言，在胃蛋白酶模拟胃液消化后，帕利珠单抗减少了 50%，在胰蛋白酶模拟肠液消化后减少了 62%。人乳或粪便样本中的帕利珠单抗（2-8 μg/mL）通过显微镜阻断 RSV（3.4×10 FFU/mL）感染（Hep-2 细胞上无合胞体形成）。当 RSV 在胃液或含病毒的培养基中与 2-4 μg/mL 的帕利珠单抗孵育时，在 Hep-2 细胞上检测到合胞体形成，但在 8 μg/mL 时未观察到感染。当 RSV-GFP（1.1×10 FFU/mL）与人乳或培养基中孵育帕利珠单抗（100 μg/mL）时，未检测到荧光（无感染细胞），而使用流式细胞术时，随着帕利珠单抗浓度的降低，荧光增加。这些结果表明，未消化和消化的基质可能会改变病毒病原体特异性抗体的结合和中和能力。
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