Chisholm Carly F, Soucie Kaitlin R, Song Jane S, Strauch Pamela, Torres Raul M, Carpenter John F, Ragheb Jack A, Randolph Theodore W
Department of Chemical and Biological Engineering, Center for Pharmaceutical Biotechnology, University of Colorado Boulder, Boulder, Colorado 80309.
Department of Immunology & Microbiology, University of Colorado School of Medicine, Aurora, Colorado 80045.
J Pharm Sci. 2017 Jun;106(6):1519-1527. doi: 10.1016/j.xphs.2017.02.008. Epub 2017 Feb 16.
Silicone oil microdroplets may act as adjuvants, promoting unwanted immune responses against both foreign and self-proteins. Proteins often unfold upon adsorption to silicone oil microdroplets, but it is unclear how such unfolding might affect the immune response. In this study, we found that hen egg lysozyme (HEL) readily adsorbed to silicone oil microdroplets and perturbed the conformation of HEL. We compared the immune response to injections of HEL formulated in the presence and absence of silicone oil microdroplets in both wild-type mice and transgenic littermates that express a soluble form of HEL (sHEL), thus rendering them immunologically tolerant to this nominal self-antigen. Following 2 subcutaneous injections of a HEL formulation containing silicone oil microdroplets, wild-type mice exhibited a stronger IgG1 antibody response against HEL compared to the response in wild-type mice that administered an oil-free HEL formulation. However, when HEL was subcutaneously administered to sHEL-transgenic mice, immunological tolerance to sHEL was not broken in the presence of silicone oil microdroplets. Thus, although structural perturbations in proteins adsorbed to silicone oil microdroplets may augment the immune response, in the case of endogenously expressed proteins, such structural perturbations may not be sufficient to result in a breach of immunological tolerance.
硅油微滴可能充当佐剂，促进针对外来蛋白和自身蛋白的不必要免疫反应。蛋白质吸附到硅油微滴上时常会发生解折叠，但尚不清楚这种解折叠如何影响免疫反应。在本研究中，我们发现鸡蛋清溶菌酶（HEL）很容易吸附到硅油微滴上并扰乱HEL的构象。我们比较了在野生型小鼠和表达可溶性HEL（sHEL）形式的转基因同窝小鼠中，注射有无硅油微滴情况下配制的HEL后的免疫反应，从而使它们对这种名义上的自身抗原具有免疫耐受性。在皮下注射含硅油微滴的HEL制剂两次后，与注射无油HEL制剂的野生型小鼠相比，野生型小鼠对HEL表现出更强的IgG1抗体反应。然而，当将HEL皮下注射给sHEL转基因小鼠时，在存在硅油微滴的情况下，对sHEL的免疫耐受性并未被打破。因此，尽管吸附到硅油微滴上的蛋白质的结构扰动可能增强免疫反应，但对于内源性表达的蛋白质而言，这种结构扰动可能不足以导致免疫耐受性的破坏。
