Livingston P O, Jones M, Deleo A B, Oettgen H F, Old L J
J Immunol. 1985 Aug;135(2):1505-9.
We have shown previously that the serologic response of BALB/c mice to immunization with BALB/c sarcoma Meth A cells can be more effectively augmented by pretreatment with cyclophosphamide (Cy) than by the use of adjuvants. The serologic response was directed against a highly restricted cell surface antigen, closely related to or identical with the unique transplantation antigen characteristic for this tumor. In this paper, we report the results of our attempts to obtain additional augmentation by using Cy and adjuvants together. For these studies, the optimal Cy dose, interval between Cy and vaccine administration, and vaccine cell number were determined. Mice were injected with Cy 25 mg/kg i.p., and 3 days later, with viable irradiated (10,000 rad) Meth A cells subcutaneously, under conditions in which only few mice produced antibody. Sera were tested for antibody with reactivity against Meth A by complement dependent cytotoxicity (CDCX), which predominantly detects IgM, and by the protein A (PA) and anti-IgG assays, which detect IgG. Of the various adjuvants tested, only monophosphoryl lipid A (MPLA) and CP20,961 resulted in significantly increased titers of reactivity in both the CDCX and PA assays over that obtained when using Cy alone. Although the mean titers observed with CDCX ranged between 1/160 and 1/320, no titer above 1/40 was observed with the PA assay. The specificity of the CDCX reactivity detected by the assay for the Meth A antigen was ascertained by absorption analysis of selected sera by using a panel of BALB/c spleen and tumor cell lines grown in vitro or in vivo. PA titers were too low to permit absorption analysis, and the titers obtained in the anti-IgG assay were lower still. Attempts to augment the anti-Meth A IgG response or to convert the IgM response to IgG were unsuccessful. The combined approach described here (i.e., vaccination with irradiated syngeneic tumor cells plus MPLA in Cy-pretreated mice) was also shown to be effective in augmenting the serologic response against two additional murine leukemia virus-negative sarcomas that are known to be less immunogenic, CMS4 and CMS5. It appears, therefore, that this combined approach may be applicable to stimulating serologic responses against a variety of tumor cell surface antigens.
我们之前已经表明，与使用佐剂相比，用环磷酰胺（Cy）预处理能更有效地增强BALB/c小鼠对BALB/c肉瘤Meth A细胞免疫接种的血清学反应。该血清学反应针对的是一种高度受限的细胞表面抗原，与该肿瘤特有的独特移植抗原密切相关或相同。在本文中，我们报告了尝试联合使用Cy和佐剂以获得进一步增强效果的结果。对于这些研究，确定了最佳的Cy剂量、Cy与疫苗接种之间的间隔以及疫苗细胞数量。给小鼠腹腔注射25 mg/kg的Cy，3天后，在只有少数小鼠产生抗体的条件下，皮下注射经辐照（10,000拉德）的活Meth A细胞。通过补体依赖性细胞毒性（CDCX，主要检测IgM）以及蛋白A（PA）和抗IgG检测法检测血清中针对Meth A的抗体反应性，后者检测IgG。在所测试的各种佐剂中，只有单磷酰脂质A（MPLA）和CP20,961在CDCX和PA检测中导致反应性滴度显著高于单独使用Cy时获得的滴度。尽管在CDCX中观察到的平均滴度在1/160至1/320之间，但在PA检测中未观察到高于1/40的滴度。通过使用一组在体外或体内培养的BALB/c脾细胞和肿瘤细胞系对选定血清进行吸收分析，确定了CDCX检测所检测到的针对Meth A抗原的反应性的特异性。PA滴度太低，无法进行吸收分析，而在抗IgG检测中获得的滴度更低。增强抗Meth A IgG反应或将IgM反应转化为IgG的尝试均未成功。这里描述的联合方法（即在经Cy预处理的小鼠中用辐照的同基因肿瘤细胞加MPLA进行疫苗接种）也被证明可有效增强针对另外两种已知免疫原性较低的小鼠白血病病毒阴性肉瘤CMS4和CMS5的血清学反应。因此，看来这种联合方法可能适用于刺激针对多种肿瘤细胞表面抗原的血清学反应。
