Increased Resistance to Taenia crassiceps Murine Cysticercosis in Qa-2 Transgenic Mice

We previously reported important differences in resistance to Taenia crassiceps murine cysticercosis between BALB/c substrains. It was suggested that resistance might correlate with expression of the nonclassic class I major histocompatibility complex (MHC) Qa-2 antigen; BALB/cAnN is Qa-2 negative and highly susceptible to T. crassiceps, whereas BALB/cJ expresses Qa-2 and is highly resistant. In this study, we investigated the role of Qa-2 in mediating resistance to cysticercosis by linkage analysis and infection of Qa-2 transgenic mice. In BALB/cAnN × (C57BL/6J × BALB/cAnN)F(1) and BALB/cAnN × (BALB/cJ × BALB/cAnN)F(1) backcrosses, the expression of Qa-2 antigen correlated with resistance to cysticercosis. Significantly fewer parasites were recovered from infected Qa-2 transgenic male and female mice than from nontransgenic mice of similar genetic background. These results clearly demonstrate that the Qa-2 MHC antigen is involved in resistance to T. crassiceps cysticercosis.

我们此前曾报道，不同BALB/c亚系小鼠在抗克氏带绦虫（Taenia crassiceps）鼠囊尾蚴病的能力上存在显著差异。有研究提出，该抗性可能与非经典I类主要组织相容性复合体（MHC）Qa-2抗原的表达相关：BALB/cAnN亚系小鼠Qa-2抗原呈阴性，对克氏带绦虫（T. crassiceps）感染高度易感；而BALB/cJ亚系小鼠表达Qa-2抗原，表现出高度抗性。本研究通过连锁分析以及Qa-2转基因小鼠感染实验，探究了Qa-2抗原在介导囊尾蚴病抗性中的作用。在BALB/cAnN × (C57BL/6J × BALB/cAnN)F₁以及BALB/cAnN × (BALB/cJ × BALB/cAnN)F₁回交群体中，Qa-2抗原的表达与囊尾蚴病抗性显著相关。感染后，从Qa-2转基因雌雄小鼠体内回收的寄生虫数量显著低于遗传背景一致的非转基因小鼠。上述结果明确证实，MHC-Qa-2抗原参与了抗克氏带绦虫鼠囊尾蚴病的免疫过程。