皮卡佐剂及其治疗性疫苗作用机理

Mechanisem of Action of PICKCa Adjuvant and Its Therapeutic Vaccines

摘要: 皮卡是人用安全的疫苗佐剂，是双链聚肌苷酸聚胞苷酸及微量卡那霉素和氯化钙的复合物。该佐剂是三种模式识别受体TLR3、NOD和RIG-1的配体。皮卡佐剂疫苗与受体结合后在体内活化非特异免疫，包括巨噬细胞吞噬功能，促进干扰素(IFN)、白细胞介素-2(IL-2)、-6、-12、肿瘤坏死因子(TNF)等细胞因子的产生，促进产生共刺激因子CD40、CD80、CD86，促进抗原呈递细胞的提呈、活化T淋巴细胞，促进特异性的细胞免疫和体液免疫应答，促进免疫细胞的增殖。皮卡佐剂不仅提高疫苗的免疫原性，更由于促进干扰素、白细胞介素-2、-12的产生，使从主要产生体液免疫的预防性疫苗转变成具有强烈细胞免疫的治疗性疫苗。在三次独立的先感染后免疫的暴露后小白鼠和比格犬的试验中，在没有接种抗血清情况下，国内外市售人用狂犬病疫苗保护率仅为20%~30%，而皮卡狂犬病疫苗可高达70%~100%，统计学分析具有显著的差异(P < 0.05~0.01)。皮卡狂犬病治疗性疫苗和皮卡乙肝治疗性疫苗正在新加坡进行1期临床研究。

Abstract: PICKCa, a safe vaccine adjuvant for human use, is a complex of poly IC-kanamycin-Cacl2. It is the ligand of pattern recognition receptors of TLR3, NOD and RIG-1. PICKCa vaccines can activate innate pathways in vivo to produce cytokines including IFN-α, IFN-β, IFN-γ, IL-2, IL-12p40, IL-6, TNF-α, promote macrophage function, stimulate antigen-presenting cells to produce co-stimulators of CD40, CD80, CD86, activate cell-mediated immunity and humoral immunity. Due to PICKCa adjuvant enhancing productions of IFN, IL-2, IL-12, the adjuvant may make prophylactic vaccines from main humoral immunity to possess strong cell-mediated immunity as therapeutic vaccines. In 3 independent assays of post-explosure immunizations of mice and beagle dogs, PICKCa rabies vaccine was much better than commercial adjuvant-free rabies vaccines, the protective rate was 70% - 100% and 20% - 30% respectively, and the statistical analyses were significantly different (P < 0.05 - 0.01). PICKCa rabies vaccine and PICKCa hepatitis B vaccine are ongoing in phase-1 clinical trials in Singapore.