Antitumor immunity by OK-432-conjugated tumor vaccine in mice cancer model

我们先前已经证明，OK-432缀合的肿瘤疫苗（KLN-205疫苗）在小鼠舌癌模型中强烈抑制肿瘤发病率和生长，并作为肿瘤特异性免疫提高存活率。本研究旨在阐明KLN-205疫苗诱导抗肿瘤免疫应答的机制。将6周龄雌性DBA/2小鼠单独随机化，分为三组。来源于DBA/2小鼠鳞状细胞癌的KLN-205肿瘤细胞。将KLN-205细胞与作为KLN-205疫苗的OK-432混合。将制备的KLN-205疫苗每周一次注射到小鼠体内，持续3周，分离小鼠的脾细胞并与肿瘤细胞一起培养。然后使用ELISA测量血清和培养上清液中的细胞因子。通过间接免疫过氧化物酶染色进行CD 4、CD 8、CD 25（IL-2 R α）、CD 69和CD 122（IL-2 R β）的免疫组织化学分析。当用KLN-205疫苗免疫小鼠三次时，在血清和脾细胞培养上清中观察到高于对照小鼠的INF-γ水平。KLN-205疫苗组接种肿瘤后，肿瘤细胞周围浸润的CD 4和CD 8 T细胞数量多于对照组。免疫组化结果显示，KLN-205疫苗组T细胞CD 25（IL-2 R α）、CD 69和CD 122（IL-2 R β）的表达在24 h时短暂升高。这些结果表明KLN-205疫苗诱导肿瘤特异性细胞介导的免疫并抑制肿瘤活性。

We have previously documented that OK-432-conjugated tumor vaccine (KLN-205 vaccine) strongly suppressed tumor incidence and growth, and improved survival rate as tumor-specific immunity in murine tongue cancer model. The aim of this study is to clarify the mechanisms of antitumor immune response elicited by KLN-205 vaccine. Six-week-old female DBA/2 mice were individually randomized, divided into three groups. KLN-205 tumor cells derived from the squamous cell carcinoma of DBA/2 mice. KLN-205 cells were mixed with OK-432 serviced as KLN-205 vaccine. The prepared KLN-205 vaccine was injected into mice once a week for 3 weeks, and splenetic cells from the mice were isolated and cultured with tumor cells. Cytokines in serum and culture supernatant were then measured using ELISA. Immunohistochemical analysis for CD4, CD8, CD25(IL-2Rα), CD69, and CD122(IL-2Rβ) was performed by indirect immunoperoxidase staining. When the mice were immunized with the KLN-205 vaccine three times, higher INF-y levels were seen in serum and culture supernatant of splenetic cells than the control mice. After tumor inoculation in the KLN-205 vaccine group, a greater number of CD4 and CD8 T cells had infiltrated around tumor cells than the control group. Moreover immunohistochemical results showed that the expression of CD25(IL-2Rα), CD69, and CD122(IL-2Rβ) in T cells were transiently higher by 24 hours in the KLN-205 vaccine group. These results indicated that the KLN-205 vaccine induced tumor-specific cell-mediated immunity and suppress tumor activity.