Titus M J, Bartlett G L, Kreider J W
Int J Cancer. 1982 Jun 15;29(6):699-705. doi: 10.1002/ijc.2910290617.
Immunization of mice with 10(6) irradiated LSTRA murine leukemia cells (LX) induced weak immunity to subsequent tumor-cell challenge. Admixture of low doses (1.4-14 micrograms of C. parvum with the LX usually augmented the immunity. Higher doses (1,400-7,000 micrograms) of admixed C. parvum not only failed to augment immunity, but prevented immunization by the contained LX. We investigated the mechanism by which 1,400 micrograms of C. parvum mixed with 10(6) LX prevents immunization by the LX. The inhibitory effect was a function of the ratio of C. parvum to tumor cells. Injection of 1,400 micrograms C. parvum, alone or mixed with the LX, did not prevent immunization by LX given simultaneously at a separate site. Injection of C. parvum, alone or mixed with the LX, did not prevent immunization by LX injected simultaneously at a separate site sharing a common lymph-node drainage area. The high dose of C. parvum prolonged retention of radiolabelled LX at the injection site and decreased the rate of distribution of the LX to other organs, particularly the spleen. These results indicate that a high dose of C. parvum prevented immunization through a localized process at the injection site.
用10⁶个经辐射的LSTRA小鼠白血病细胞（LX）对小鼠进行免疫接种，可诱导对后续肿瘤细胞攻击的弱免疫力。低剂量（1.4 - 14微克）的微小隐孢子虫与LX混合通常会增强免疫力。高剂量（1400 - 7000微克）的混合微小隐孢子虫不仅未能增强免疫力，反而阻止了所含LX的免疫接种作用。我们研究了1400微克微小隐孢子虫与10⁶个LX混合后阻止LX免疫接种的机制。抑制作用是微小隐孢子虫与肿瘤细胞比例的函数。单独注射1400微克微小隐孢子虫或与LX混合注射，均不能阻止在另一个部位同时注射的LX的免疫接种作用。在共享一个共同淋巴结引流区域的另一个部位同时注射LX时，单独注射微小隐孢子虫或与LX混合注射，均不能阻止其免疫接种作用。高剂量的微小隐孢子虫使放射性标记的LX在注射部位的滞留时间延长，并降低了LX向其他器官，特别是脾脏的分布速率。这些结果表明，高剂量的微小隐孢子虫通过注射部位的局部过程阻止了免疫接种。
