Novartis Vaccines Institute for Global Health, Siena, Italy.
Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Switzerland.
Vaccine. 2014 May 13;32(23):2688-95. doi: 10.1016/j.vaccine.2014.03.068. Epub 2014 Apr 3.
Neisseria meningitidis causes epidemics of meningitis in sub-Saharan Africa. These have mainly been caused by capsular group A strains, but W and X strains are increasingly contributing to the burden of disease. Therefore, an affordable vaccine that provides broad protection against meningococcal disease in sub-Saharan Africa is required.
We prepared Generalized Modules for Membrane Antigens (GMMA) from a recombinant serogroup W strain expressing PorA P1.5,2, which is predominant among African W isolates. The strain was engineered with deleted capsule locus genes, lpxL1 and gna33 genes and over-expressed fHbp variant 1, which is expressed by the majority of serogroup A and X isolates.
We screened nine W strains with deleted capsule locus and gna33 for high-level GMMA release. A mutant with five-fold increased GMMA release compared with the wild type was further engineered with a lpxL1 deletion and over-expression of fHbp. GMMA from the production strain had 50-fold lower ability to stimulate IL-6 release from human PBMC and caused 1000-fold lower TLR-4 activation in Human Embryonic Kidney cells than non-detoxified GMMA. In mice, the GMMA vaccine induced bactericidal antibody responses against African W strains expressing homologous PorA and fHbp v.1 or v.2 (geometric mean titres [GMT]=80,000-200,000), and invasive African A and X strains expressing a heterologous PorA and fHbp variant 1 (GMT=20-2500 and 18-5500, respectively). Sera from mice immunised with GMMA without over-expressed fHbp v.1 were unable to kill the A and X strains, indicating that bactericidal antibodies against these strains are directed against fHbp.
A GMMA vaccine produced from a recombinant African N. meningitidis W strain with deleted capsule locus, lpxL1, gna33 and overexpressed fHbp v.1 has potential as an affordable vaccine with broad coverage against strains from all main serogroups currently causing meningococcal meningitis in sub-Saharan Africa.
脑膜炎奈瑟菌在撒哈拉以南非洲引发了脑膜炎的流行。这些流行主要是由荚膜组 A 菌株引起的，但 W 和 X 菌株对疾病负担的贡献越来越大。因此，需要一种负担得起的疫苗，为撒哈拉以南非洲的脑膜炎球菌病提供广泛的保护。
我们从表达 PorA P1.5,2 的重组 W 血清群菌株中制备了通用膜抗原（GMMA），该菌株在非洲 W 分离株中占优势。该菌株经过基因工程改造，缺失了荚膜基因座基因 lpxL1 和 gna33，并过表达了大多数 A 和 X 血清群分离株表达的 fHbp 变体 1。
我们筛选了 9 株具有缺失荚膜基因座和 gna33 的 W 株，以获得高水平的 GMMA 释放。与野生型相比，GMMA 释放增加了五倍的突变体进一步进行了 lpxL1 缺失和 fHbp 的过表达。与未解毒的 GMMA 相比，生产菌株的 GMMA 从人 PBMC 释放 IL-6 的能力低 50 倍，对人胚肾细胞中 TLR-4 的激活作用低 1000 倍。在小鼠中，GMMA 疫苗诱导了针对表达同源 PorA 和 fHbp v.1 或 v.2 的非洲 W 株的杀菌抗体反应（几何平均滴度 [GMT]=80,000-200,000），以及表达异源 PorA 和 fHbp 变体 1 的侵袭性非洲 A 和 X 株（GMT=20-2500 和 18-5500）。用未过表达 fHbp v.1 的 GMMA 免疫的小鼠血清不能杀死 A 和 X 株，表明针对这些株的杀菌抗体针对 fHbp。
从缺失荚膜基因座、lpxL1、gna33 和过表达 fHbp v.1 的重组非洲 N. meningitidis W 菌株中生产的 GMMA 疫苗具有作为一种负担得起的疫苗的潜力，对目前在撒哈拉以南非洲引起脑膜炎球菌性脑膜炎的所有主要血清群菌株具有广泛的覆盖范围。
