The Vaccine
Onchocerciasis (river blindness) vaccine candidates
| Antigen (expression system) |
Location | In vitro L3 killing |
In vivo L3 killing |
In vivo Adult killing |
In vivo Microfilaria killing |
|---|---|---|---|---|---|
| CPI-2M (bacteria ) |
ES, Surface, all stages |
Ov L3 94% |
Ov >30% (rProtein ) |
Ls 50% (rProtein ) Bm >45% (rProtein) Ls 70% (DNA) |
Ls >85% (DNA) Ls >85% (synthetic peptide) |
| RAL-2 (bacteria) |
ES, surface, all stages |
Ov L3 100% |
Ov >40% (rProtein ) |
Bm >60% (rProtein ) |
Bm >90% (rProtein ) |
| 103 (yeast) |
Surface, all stages |
Ov L3 100% Ov Mf >90% |
Ov >35% (rProtein ) |
Bm >40% (rProtein) |
Ls >90% (DNA) |
Onchocerciasis (river blindness) vaccine candidatesPercentages represent killing in vitro (human antigen-specific antibodies + neutrophils) or reduction in parasite burden in vivo
ES, excreted-secreted antigens
rProtein, recombinant protein
Ov, Onchocerca volvulus
Bm, Brugia malayi
Ls, Litomosoides sigmodontis
L3, third stage infective larvae
Mf, microfilaria
Protecting children, reducing morbidity and transmission
Our goal is production and testing of a river blindness vaccine through Phase I trials by 2022.
It is envisaged that the onchocerciasis vaccine will be used initially to protect vulnerable children (<5 years of age) living in loiasis co-endemic areas. The vaccine will reduce adult worm burden and fecundity with consequential reduction in pathology associated with microfilariae. In addition, a vaccine will find use in ongoing ivermectin MDA areas and contribute to reduction in transmission rates; and, will protect areas where local elimination may have been achieved.