Myllymäki Henna, Niskanen Mirja, Oksanen Kaisa Ester, Sherwood Eleanor, Ahava Maarit, Parikka Mataleena, Rämet Mika
BioMediTech Institute and Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland.
Oral and Maxillofacial Unit, Tampere University Hospital, Tampere, Finland.
PLoS One. 2017 Jul 25;12(7):e0181942. doi: 10.1371/journal.pone.0181942. eCollection 2017.
Tuberculosis (TB) remains a major global health challenge and the development of a better vaccine takes center stage in fighting the disease. For this purpose, animal models that are capable of replicating the course of the disease and are suitable for the early-stage screening of vaccine candidates are needed. A Mycobacterium marinum infection in adult zebrafish resembles human TB. Here, we present a pre-clinical screen for a DNA-based tuberculosis vaccine in the adult zebrafish using an M. marinum infection model. We tested 15 antigens representing different types of mycobacterial proteins, including the Resuscitation Promoting factors (Rpf), PE/PPE protein family members, other membrane proteins and metabolic enzymes. The antigens were expressed as GFP fusion proteins, facilitating the validation of their expression in vivo. The efficiency of the antigens was tested against a low-dose intraperitoneal M. marinum infection (≈ 40 colony forming units), which mimics a primary M. tuberculosis infection. While none of the antigens was able to completely prevent a mycobacterial infection, four of them, namely RpfE, PE5_1, PE31 and cdh, led to significantly reduced bacterial burdens at four weeks post infection. Immunization with RpfE also improved the survival of the fish against a high-dose intraperitoneal injection with M. marinum (≈ 10.000 colony forming units), resembling the disseminated form of the disease. This study shows that the M. marinum infection model in adult zebrafish is suitable for the pre-clinical screening of tuberculosis vaccines and presents RpfE as a potential antigen candidate for further studies.
结核病仍然是一项重大的全球卫生挑战，开发更好的疫苗是抗击该疾病的核心任务。为此，需要能够复制疾病进程且适用于候选疫苗早期筛选的动物模型。成年斑马鱼感染海分枝杆菌类似于人类结核病。在此，我们利用海分枝杆菌感染模型，对成年斑马鱼中一种基于DNA的结核病疫苗进行临床前筛选。我们测试了15种代表不同类型分枝杆菌蛋白的抗原，包括复苏促进因子（Rpf）、PE/PPE蛋白家族成员、其他膜蛋白和代谢酶。这些抗原被表达为绿色荧光蛋白（GFP）融合蛋白，便于在体内验证其表达。针对低剂量腹腔注射海分枝杆菌（约40个菌落形成单位）测试了这些抗原的有效性，这种注射模拟了原发性结核分枝杆菌感染。虽然没有一种抗原能够完全预防分枝杆菌感染，但其中四种，即RpfE、PE5_1、PE31和cdh，在感染后四周导致细菌载量显著降低。用RpfE免疫也提高了鱼在高剂量腹腔注射海分枝杆菌（约10000个菌落形成单位）后的存活率，这种注射类似于疾病的播散形式。这项研究表明，成年斑马鱼中的海分枝杆菌感染模型适用于结核病疫苗的临床前筛选，并将RpfE作为进一步研究的潜在抗原候选物。
