Validation of the protective Ostertagia ostertagi ES‐thiol antigens with different adjuvantia

Abstract

Intramuscular immunization of calves with an excretory-secretory antigen fraction enriched for cysteine proteinase activity (ES-thiol) and QuilA as adjuvant induces a protective immune response against the abomasal nematode Ostertagia ostertagi. The objectives of the present study were to confirm the protective capacity of ES-thiol in combination with QuilA, to test Al(OH)(3) as adjuvant for vaccination against O. ostertagi and to look for correlations between protection and immunological effector responses. Calves(seven animals/group) were vaccinated three times intramuscularly with 100 micro g antigen and/or adjuvant (ES-thiol with QuilA, ES-thiol with Al(OH)(3), QuilA alone and Al(OH)(3) alone) and subsequently challenged with a trickled oral infection of 25 000 infective larvae in total over 25 days. Faecal egg counts in the ES-thiol QuilA group were reduced by 56% during the two-month period of the trial compared to the QuilA control group (P < 0.002). Calves immunized with ES-thiol QuilA had significantly smaller adult worms (P < 0.002) and less eggs/female worm (P < 0.05) compared to the QuilA control group. No differences in egg output, worm counts or parameters of worm fitness were observed in the ES-thiol Al(OH)(3) group compared to the Al(OH)(3) control group. Although the protective immune mechanism against O. ostertagi remains unknown, protection in the ES-thiol QuilA group was associated with high levels of parasite-specific antibodies in the abomasal mucosa.

Granule Exocytosis of Granulysin and Granzyme B as a Potential Key Mechanism in Vaccine-Induced Immunity in Cattle against the Nematode Ostertagia ostertagi

“…After the final immunization, the animals were challenged with a trickle infection of 30,000 infective L3 larvae (1,000 L3 larvae/day for 30 days, 5 days a week, for a period of 6 weeks). Three weeks after the last challenge infection, all animals were sacrificed and parasitological parameters (i.e., fecal egg counts, worm counts, and worm lengths) were analyzed as described in previous trials (13,14,16).…”

“…These responses, however, fail to provide the host with a sufficient level of protection, or this level of protection is obtained only after a prolonged period. To date, only a few candidate vaccines against mucus-dwelling parasites have been developed; one of the most promising is an O. ostertagi vaccine that is based on excretory-secretory (ES) material of the parasite (13,14). Although these experimental vaccines provide the host with significant levels of protection, mimicking this response by using a recombinant version of the antigen, the absolute requirement of the economic viability of a vaccine remains difficult to meet and is currently the main bottleneck in the process of vaccine development (6).…”

Parasite Vaccines: Recent Progress in, and Problems Associated with their Development

“…Suffice to say here that the wrong choice of adjuvant can lead to misleading experimental outcomes with the result that good vaccine candidates may be rejected simply because inappropriate adjuvanting or delivery was used in the initial phases of testing. This is exemplified by a body of work investigating adult ES products as vaccine candidates against O. ostertagi in cattle [124]. One component, an ASP homologue was efficacious when given intramuscularly with QuilA as adjuvant but had no effect with aluminium hydroxide as adjuvant [124].…”

“…This is exemplified by a body of work investigating adult ES products as vaccine candidates against O. ostertagi in cattle [124]. One component, an ASP homologue was efficacious when given intramuscularly with QuilA as adjuvant but had no effect with aluminium hydroxide as adjuvant [124].…”

Gender-enriched transcription of activation associated secreted proteins in Ostertagia ostertagi

“…They are of general interest as they have shown their protective capacity in multiple vaccination trials against Ancylostoma spp., H. contortus and O. ostertagi (Schallig et al, 1997a;Ghosh and Hotez, 1999;Geldhof et al, 2002Geldhof et al, , 2004Goud et al, 2004;Meyvis et al, 2007). Three types of ASP proteins have been identified in nematodes: long ASP proteins composed of two distinct but related domains and short ASP molecules that show similarity to either the C-terminal or the N-terminal domain of the double-domain ASP.…”