Williams D J, Behnke J M
Immunology. 1983 Jan;48(1):37-47.
The nematode parasite Nematospiroides dubius survives to give a chronic primary infection in mice. However, mice subjected to weekly infections of 125 larvae, interspersed by treatment with an anthelmintic to prevent the accumulation of lethal numbers of adult worms in the intestine, develop host-protective antibodies in their serum. The protective effect of these antibodies was demonstrated by passive transfer to naive recipients or to mice already adoptively immunized with immune mesenteric lymph node cells (IMLNC). Sera were first shown to exhibit protective activity during the third and fourth weeks of the multiple immunizing infection, reaching a peak level by week six beyond which there was no further increase in protective activity. This increase was correlated with a ten-fold, concurrent rise in serum IgG1 levels. None of the other immunoglobulin isotypes underwent comparable changes in concentration nor could they be correlated with the pattern of appearance of host-protective antibodies in the sera of donor mice. This suggested that host protective antibodies were of the IgG1 class. CFLP and C57BL10 mice (the latter is a weak responder strain) both had high levels of host-protective antibodies in their serum. However when the sera from NIH mice (a strong responder strain) were compared, they exhibited far less protective activity on passive transfer to recipient mice, although when given together with IMLNC, serum from multiply-immunized NIH mice enhanced the protective effect of IMLNC synergistically. When primary infection serum was assayed in this passive/adoptive transfer model, no host-protective antibodies could be demonstrated, even with pools of primary infection serum taken 10 and 17 weeks after infection. These results are discussed with respect to the possible mechanisms by which N. dubius evades the host immune system to give rise to long-lasting primary infections in mice.
线虫寄生虫双睾旋尾线虫能在小鼠体内存活并引发慢性原发性感染。然而，每周感染125条幼虫并穿插使用驱虫药以防止肠道内成虫数量累积至致死水平的小鼠，其血清中会产生宿主保护性抗体。通过将血清被动转移至未感染的受体小鼠或已用免疫肠系膜淋巴结细胞（IMLNC）进行过适应性免疫的小鼠体内，证明了这些抗体的保护作用。血清首先在多次免疫感染的第三和第四周表现出保护活性，到第六周达到峰值水平，此后保护活性不再进一步增加。这种增加与血清IgG1水平同时升高十倍相关。其他免疫球蛋白同种型的浓度均未发生类似变化，也无法与供体小鼠血清中宿主保护性抗体的出现模式相关联。这表明宿主保护性抗体属于IgG1类。CFLP和C57BL10小鼠（后者是弱应答品系）血清中均具有高水平的宿主保护性抗体。然而，当比较NIH小鼠（强应答品系）的血清时，尽管多次免疫的NIH小鼠血清与IMLNC一起给予时能协同增强IMLNC的保护作用，但将其被动转移至受体小鼠时，其表现出的保护活性要低得多。在这种被动/适应性转移模型中检测原发性感染血清时，即使使用感染后10周和17周采集的原发性感染血清池，也未发现宿主保护性抗体。针对双睾旋尾线虫逃避宿主免疫系统从而在小鼠体内引发持久原发性感染感染的可能的机制，对这些结果进行了讨论。
