DEVELOPMENT OF A LEISHMANIA VACCINES

皮肤利什曼病每年仍影响约1000万人，尽管在病媒控制、寄生虫根除和各种疫苗配方的创造方面进行了许多尝试。 在人类自然感染所有皮肤种属后，产生固体免疫。 用活寄生虫接种疫苗，或利什曼化，只在皮肤利什曼病流行的地区进行过试验。 由于使用了活的寄生虫，所诱发的病变常常并发长期溃疡和瘢痕形成。 用灭活制剂接种疫苗仅在少数人中显示出免疫原性，并且从未在大规模试验中显示出有效性。 最近使用小鼠模型的观察表明，白细胞介素-12可以逆转易感BALB/c小鼠的免疫应答时，作为佐剂与粗利什曼原虫疫苗制剂。 在几家制药公司的合作下，我们正在开发一种用于人体临床试验的产品。虽然小鼠模型已经显示出当与IL-12组合时几种抗原是有效的，但是迫切需要证实用细胞因子佐剂在人中接种的潜力，并确保粗制品的安全性和免疫原性。 我们已经完成了一系列使用小鼠和恒河猴的实验，以测试几种制剂的安全性、效力、有效性和稳定性。 疫苗抗原是在我们的实验室从寄生虫的培养物中制备的，这些寄生虫经过洗涤，然后冷冻和解冻几次以破坏细胞。 这些粗制利什曼原虫制剂显示出尽管高压灭菌也能很好地工作，并且高压灭菌的制剂在37！C. 已提交IND进行I/II期临床试验，目前处于临床暂停状态。 其他疫苗策略的临床前研究已经开始，包括DNA疫苗接种和使用CpG寡核苷酸作为佐剂。

Cutaneous leishmaniasis still affects about 10 million people a year, despite numerous attempts at vector control, parasite eradication, and creation of various vaccine formulations. Solid immunity develops after natural infection in humans with all cutaneous species. Vaccination against the disease with living parasites, or leishmanization, has only been tried in areas where cutaneous leishmaniasis is endemic. The lesion induced is often complicated by prolonged ulceration and scarring since live parasites are used. Vaccination with killed preparations has only been shown to be immunogenic in small numbers of people, and has never been shown to be effective in large trials. Recent observations using the mouse model have shown that Interleukin-12 can reverse the immune response of susceptible BALB/c mice when used as an adjuvant with a crude leishmania vaccine preparation. With the cooperation of several pharmaceutical companies, we are developing a product for use in human clinical trials. While the mouse model has shown several antigens to be efficacious when combined with IL-12, there is an urgent need to confirm the potential for vaccination in humans with the cytokine adjuvant, and to assure the community of the safety and immuno- genicity of a crude preparation. We have completed a series of experiments using mice and rhesus macaques to test the safety, potency, efficacy, and stability of several preparations. The vaccine antigen was made in our labs from cultures of parasites that are washed, then frozen and thawed several times to break the cells. These crude leishmania preps were shown to work well despite autoclaving, and the autoclaved preparation remains stable after one month at 37!C. An IND has been submitted for the Phase I/II clinical trial, which is currently on clinical hold. Preclinical studies for other vaccine strategies have been initiated including DNA vaccination and the use of CpG oligonucleotides as an adjuvant.