Faecal egg output, adult worm burdens and ELISA antibody responses following vaccination with rH11-4/5 co-expressed proteins or with native H11-enriched extract. Faecal egg count (FEC) (A) was monitored from days 14–34 post-challenge infection and adult worm burdens (B) counted at necropsy on day 35. The mean group count from lambs vaccinated with rH11-4 /5 proteins, native H11-enriched extract or Vax Saponin adjuvant are shown, with error bars representing the standard error of the mean. (C) ELISA OD values of antisera (1/800 dilution) reactivity to rH11-4/5 co-expressed proteins or native H11 extract following immunisation with the homologous antigen. Lambs were vaccinated on days 0, 21 and 42 and challenged with 5000 L3 on day 42, as indicated. (D) Ig isotype responses (1/50 dilution) to native H11-enriched extract measured by ELISA.