title: Protective immunization of calves against Ostertagia ostertagi using fourth stage larval extracts.
abstract: ConA lectin was used to isolate glycoproteins from detergent extracts of fourth stage Ostertagia ostertagi larvae. This preparation contained proteins additional to those observed in a similar fraction prepared from adult O. ostertagi. Two vaccine trials were conducted with this preparation, and sub-fractions thereof, in groups of 6-8 worm-free calves. All groups were challenged with 50,000 O. ostertagi larvae 1 week after the final immunization, and protection was assessed by comparing the egg and worm counts of the immunized groups with their respective controls. Immunization with the ConA-binding antigen or its sub-fractions induced high titre serum antibody responses. In the first trial, the cumulative egg count of the group immunized with unfractionated antigen was 60% lower than the corresponding control value, and worm counts were 47% lower. In the second trial, the cumulative egg counts of the vaccinated groups ranged from 70% to 85% lower than the corresponding controls, with worm counts up to 64% lower. It was concluded that detergent-soluble, ConA-binding extracts prepared from O. ostertagi fourth stage larvae contained protective immunogens that were as effective as the best antigens published for O. ostertagi to date.
authors.affiliation: Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Scotland, UK. Aileen.Halliday@moredun.ac.uk
authors.forename: A M
authors.initials: AM
authors.lastname: Halliday
authors.forename: W D
authors.initials: WD
authors.lastname: Smith
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000517:prevention & control*; D003208:Concanavalin A / Q000737:chemistry / Q000276:immunology; D006023:Glycoproteins / Q000276:immunology / Q000302:isolation & purification; D015801:Helminth Proteins / Q000276:immunology* / Q000302:isolation & purification; D007114:Immunization; D007814:Larva / Q000737:chemistry / Q000276:immunology; D010028:Ostertagia / Q000737:chemistry / Q000276:immunology*; D010029:Ostertagiasis / Q000097:blood / Q000517:prevention & control* / Q000662:veterinary*; D016896:Treatment Outcome; D014612:Vaccines / Q000737:chemistry / Q000276:immunology / Q000627:therapeutic use*
chemical_list: D000276:Adjuvants, Immunologic; D000909:Antibodies, Helminth; D006023:Glycoproteins; D015801:Helminth Proteins; D014612:Vaccines; D003208:Concanavalin A