Table 1. Characteristics of the antigens.
| Designation (GenBank accession no.) | Description | Evidence for protectionb | Optimal adjuvant | Stage of expression | Percent highly, poorly, and non-immunoresponsive calvesa | |
| IgG1c | IgG2c | |||||
| OoALT1 (EU573935) | Secreted larval acidic protein, ‘abundant larval transcript’ [43],[44] | Mouse [44],[45], human [45] | Alum [45] | L2, L3 [43],[44] | 100, 0, 0 (0, 23, 77) | 8, 92, 0 (0, 8, 92) |
| OoB8* (EU573934) | Uncharacterised [45] | Mouse, human [45] | Alum [45] | All [45] | 67, 33, 0 (8, 23, 69) | 0, 100, 0 (0, 15, 85) |
| OoRAL2 (EU573933) | Uncharacterised [46] | Moused, human [46], chimpanzee [47] | Freund'sd | L3, adult [46] | 100, 0, 0 (23, 23, 54) | 92, 8, 0 (8, 23, 69) |
| OoTMY1* (EU573931) | Tropomyosin moiety [33] | Human [33], jird [38] | Freund's [38] | All [33] | 100, 0, 0 (54, 46, 0) | 67, 33, 0 (15, 31, 54) |
| OoCPI (EU573930) | Cysteine protease inhibitor, ‘onchocystatin’ [48],[49] | Mouse, human [45] | Alum [45] | Egg, L3, L4, adult [48] | 100, 0, 0 (23, 23, 54) | 0, 100, 0 (0, 31, 69) |
| OoB20* (EU573937) | Uncharacterised [50] | Cow, jird [51] | Freund's [51] | Mf, L2, L3, L4 [50] | 100, 0, 0 (8, 23, 69) | 17, 83, 0 (0, 0, 100) |
| OoFAR1 (EU573932) | Fatty acid retinoid-binding protein [52] | Jird [53], human [40] | Freund's [53] | All [53] | 100, 0, 0 (23, 23, 54) | 100, 0, 0 (0, 31, 69) |
| OoFBA* (EU573936) | Fructose-1,6-bisphosphate aldolase [34] | Mouse [34] | Freund's [34] | All [34] | 100, 0, 0 (31, 31, 38) | 100, 0, 0 (0, 15, 85) |
Notes Mf, microfilaria; L2–4, larval developmental stages.
*: These antigens represent truncated polypeptides, not full-length proteins.
Vaccinated calves (n = 12) received all eight antigens in separate inoculations with the respective optimal adjuvant; data in parentheses are comparative values for adjuvant-control animals that received adjuvants only (n = 13).
‘Mouse’ refers to the Onchocerca volvulus L3 chamber model; ‘jird’ to the filarial parasite Acanthocheilonema viteae in its natural rodent host, Meriones unguiculatus; ‘cow’ to O. lienalis in its natural host; ‘chimpanzee’ to experimental infection with O. volvulus; and ‘human’ to serological recognition by putatively immune individuals from areas endemic for O. volvulus infection.
Highly, poorly and non-immunoresponsive animals exhibited OD405 nm>1.0, 0.1–1.0, or <0.1 units (respectively) immediately before natural exposure to infection. Prior correction for non-specific binding was achieved by subtraction of OD405 nm for a pool of negative control sera (obtained from 6 unexposed calves that received neither antigens nor adjuvants).
D. Abraham, unpublished data.