title: Production of anti-idiotypic antibodies resembling bovine somatotropin by active immunization of lactating cows.
abstract: Anti-idiotypic antibodies produced in lactating cows by immunization with rabbit antibodies raised against bovine somatotropin (bST) were evaluated for bST-like immunoactive and biological activities. Twenty New Zealand White rabbits were immunized against bST. Serum was purified using protein A-Sepharose CL-4B and bST-Sepharose 4B affinity chromatography to yield specific anti-bST immunoglobulin G (IgG). Twenty-four lactating cows were allocated to a randomized complete block design and were immunized with either: (1) rabbit anti-bST (n = 12) or (2) non-specific rabbit IgG (n = 12, control). Cows were immunized starting at day 68 of lactation with 800 micrograms antigen emulsified with Freund's complete adjuvant and 1 mg Quil A administered by i.m. injections. Repeated immunizations of 800 micrograms antigen in Freund's incomplete adjuvant and 1 mg Quil A followed after 3 weeks and then every 5 weeks throughout lactation. Serum samples were collected twice weekly and were analysed for anti-rabbit IgG titre and immunoactive bST concentration by radioimmunoassay. All cows developed antibodies against rabbit IgG by the second and third immunizations. With rising titres, immunoactive bST concentrations increased in cows treated with anti-bST following each of the six repeated immunizations to 4.7 +/- 3.3, 10.0 +/- 4.2, 12.0 +/- 4.8, 17.3 +/- 6.7, 24.0 +/- 10.0 and 36.3 +/- 20.4 ng/ml (mean +/- S.E.M.) compared with controls (0.81 +/- 0.09 ng/ml, overall mean +/- S.E.M.). To assess the biological activity of these bST anti-idiotypic antibodies, milk yield and serum insulin-like growth factor-I (IGF-I) concentrations were analysed in all cows and a subset of six cows per treatment respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Animal and Poultry Science, University of Guelph, Ontario, Canada.
authors.forename: C L
authors.initials: CL
authors.lastname: Schalla
authors.forename: S
authors.initials: S
authors.lastname: Roberge
authors.forename: B N
authors.initials: BN
authors.lastname: Wilkie
authors.forename: B W
authors.initials: BW
authors.lastname: McBride
authors.forename: J S
authors.initials: JS
authors.lastname: Walton
mesh_terms: D000818:Animals; D000906:Antibodies / Q000008:administration & dosage; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis*; D002417:Cattle / Q000097:blood / Q000276:immunology*; D005260:Female; D013006:Growth Hormone / Q000097:blood / Q000276:immunology*; D007116:Immunization, Passive; D007074:Immunoglobulin G / Q000008:administration & dosage; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007774:Lactation / Q000276:immunology*; D011247:Pregnancy; D011817:Rabbits; D011863:Radioimmunoassay; D011897:Random Allocation
chemical_list: D000906:Antibodies; D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone