ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal; Instituto de Biologia Molecular e Celular - IBMC, Porto, Portugal.
Immunology. 2014 Feb;141(2):256-67. doi: 10.1111/imm.12191.
Neospora caninum is an Apicomplexa parasite that in the last two decades was acknowledged as the main pathogenic agent responsible for economic losses in the cattle industry. In the present study, the effectiveness of intranasal immunization with N. caninum membrane antigens plus CpG adjuvant was assessed in a murine model of intragastrically established neosporosis. Immunized mice presented a lower parasitic burden in the brain on infection with 5 × 10(7) tachyzoites, showing that significant protection was achieved by this immunization strategy. Intestinal IgA antibodies raised by immunization markedly agglutinated live N. caninum tachyzoites whereas previous opsonization with IgG antibodies purified from immunized mice sera reduced parasite survival within macrophage cells. Although an IgG1 : IgG2a ratio < 1 was detected in the immunized mice before and after infection, indicative of a predominant T helper type 1 immune response, no increased production of interferon-γ was detected in the spleen or mesenteric lymph nodes of the immunized mice. Altogether, these results show that mucosal immunization with N. caninum membrane proteins plus CpG adjuvant protect against intragastrically established neosporosis and indicate that parasite-specific mucosal and circulating antibodies have a protective role against this parasitic infection.
刚地弓形虫是顶复门的寄生虫，在过去二十年中被认为是导致牛养殖业经济损失的主要病原。在本研究中，通过鼻腔内免疫刚地弓形虫膜抗原加 CpG 佐剂，评估了其在经口感染建立的弓形虫病小鼠模型中的效果。用 5×10(7)速殖子感染后，免疫组小鼠脑部寄生虫负荷降低，表明这种免疫策略可显著提供保护。免疫产生的肠黏膜 IgA 抗体可明显凝集活的刚地弓形虫速殖子，而先前用从免疫鼠血清中纯化的 IgG 抗体调理可减少寄生虫在巨噬细胞内的存活。尽管在感染前后，免疫小鼠中检测到 IgG1:IgG2a 比值<1，表明存在主要的辅助性 T 细胞 1 型免疫应答，但在免疫小鼠的脾脏或肠系膜淋巴结中未检测到干扰素-γ的增加。综上所述，这些结果表明，用刚地弓形虫膜蛋白加 CpG 佐剂进行黏膜免疫可预防经口感染建立的弓形虫病，并表明寄生虫特异性黏膜和循环抗体在针对这种寄生虫感染中具有保护作用。
