Matos Marina N, Cazorla Silvia I, Schulze Kai, Ebensen Thomas, Guzmán Carlos A, Malchiodi Emilio L
Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Inmunología and Instituto de Estudios de la Inmunidad Humoral (IDEHU), UBA-CONICET, Buenos Aires, Argentina.
Universidad de Buenos Aires, Facultad de Medicina, Departamento de Microbiología, Parasitología e Inmunología and Instituto de Microbiología y Parasitología Médica (IMPaM), UBA-CONICET, Buenos Aires, Argentina.
PLoS Negl Trop Dis. 2017 Feb 24;11(2):e0005300. doi: 10.1371/journal.pntd.0005300. eCollection 2017 Feb.
The development of new adjuvants enables fine modulation of the elicited immune responses. Ideally, the use of one or more adjuvants should result in the induction of a protective immune response against the specific pathogen. We have evaluated the immune response and protection against Trypanosoma cruzi infection in mice vaccinated with recombinant Tc52 or its N- and C-terminal domains (NTc52 and CTc52) adjuvanted either with the STING (Stimulator of Interferon Genes) agonist cyclic di-AMP (c-di-AMP), a pegylated derivative of α-galactosylceramide (αGC-PEG), or oligodeoxynucleotides containing unmethylated CpG motifs (ODN-CpG). All groups immunized with the recombinant proteins plus adjuvant: Tc52+c-di-AMP, NTc52+c-di-AMP, CTc52+c-di-AMP, NTc52+c-di-AMP+αGC-PEG, NTc52+CpG, developed significantly higher anti-Tc52 IgG titers than controls. Groups immunized with c-di-AMP and Tc52, NTc52 or CTc52 showed the highest Tc52-specific IgA titers in nasal lavages. All groups immunized with the recombinant proteins plus adjuvant developed a strong specific cellular immune response in splenocytes and lymph node cells with significant differences for groups immunized with c-di-AMP and Tc52, NTc52 or CTc52. These groups also showed high levels of Tc52-specific IL-17 and IFN-γ producing cells, while NTc52+CpG group only showed significant difference with control in IFN-γ producing cells. Groups immunized with c-di-AMP and Tc52, NTc52 or CTc52 developed predominantly a Th17 and Th1immune response, whereas for NTc52+CpG it was a dominant Th1 response. It was previously described that αGC-PEG inhibits Th17 differentiation by activating NKT cells. Thus, in this work we have also included a group immunized with both adjuvants (NTc52+c-di-AMP+αGC-PEG) with the aim to modulate the Th17 response induced by c-di-AMP. This group showed a significant reduction in the number of Tc52-specific IL-17 producing splenocytes, as compared to the group NTc52+c-di-AMP, which has in turn correlated with a reduction in protection against infection. These results suggest that the Th17 immune response developed after immunizing with NTc52+c-di-AMP could have a protective role against T. cruzi infection. Groups NTc52+c-di-AMP, Tc52+c-di-AMP and NTc52PB, were the ones that showed better protection against infection with lower parasitemia and weight loss, and higher survival.
新型佐剂的研发能够对引发的免疫反应进行精细调节。理想情况下，使用一种或多种佐剂应能诱导针对特定病原体的保护性免疫反应。我们评估了用重组Tc52或其N端和C端结构域（NTc52和CTc52）接种的小鼠针对克氏锥虫感染的免疫反应和保护作用，这些重组蛋白分别与STING（干扰素基因刺激物）激动剂环二腺苷酸（c-di-AMP）、α-半乳糖神经酰胺的聚乙二醇化衍生物（αGC-PEG）或含有未甲基化CpG基序的寡脱氧核苷酸（ODN-CpG）联合作为佐剂。所有用重组蛋白加佐剂免疫的组：Tc52 + c-di-AMP、NTc52 + c-di-AMP、CTc52 + c-di-AMP、NTc52 + c-di-AMP + αGC-PEG、NTc52 + CpG，产生的抗Tc52 IgG滴度均显著高于对照组。用c-di-AMP与Tc52、NTc52或CTc52免疫的组在鼻腔灌洗液中显示出最高的Tc52特异性IgA滴度。所有用重组蛋白加佐剂免疫的组在脾细胞和淋巴结细胞中均产生了强烈的特异性细胞免疫反应，用c-di-AMP与Tc52、NTc52或CTc52免疫的组之间存在显著差异。这些组还显示出高水平的产生Tc52特异性IL-17和IFN-γ的细胞，而NTc52 + CpG组仅在产生IFN-γ的细胞方面与对照组有显著差异。用c-di-AMP与Tc52、NTc52或CTc52免疫的组主要产生Th17和Th1免疫反应，而NTc52 + CpG组则以Thl反应为主导。先前有报道称αGC-PEG通过激活NKT细胞抑制Th17分化。因此，在本研究中，我们还纳入了一组同时用两种佐剂免疫的组（NTc52 + c-di-AMP + αGC-PEG），旨在调节由c-di-AMP诱导的Th17反应。与NTc52 + c-di-AMP组相比，该组产生Tc52特异性IL-17的脾细胞数量显著减少，这反过来又与感染保护作用的降低相关。这些结果表明，用NTc52 + c-di-AMP免疫后产生的Th17免疫反应可能对克氏锥虫感染具有保护作用。NTc52 + c-di-AMP、Tc52 + c-di-AMP和NTc52PB组在感染保护方面表现更佳，寄生虫血症和体重减轻较低，存活率更高。
