Anti-idiotypic responses of lactating cows immunized with monoclonal antibodies against bovine somatotropin.
The objective of this study was to produce anti-idiotypic antibodies with bovine somatotropin (bST)-like activity by active immunization of lactating cows and to determine their effects on milk yield. Several monoclonal antibodies against bST were evaluated for their interaction with bST in a rat growth bioassay. Two bST-agonist monoclonal antibodies (1 and 2), and two bST-antagonist monoclonal antibodies (3 and 4) were selected. Cows were immunized with immunoglobulin G as a control (n = 12) or with one of the four anti-bST monoclonal antibodies (1, 2, 3, 4; n = 12) on d 3, 24, 45, 66, 87, 108, 129, and 150 of lactation. From wk 3 of lactation, all cows immunized with each of the four anti-bST monoclonal antibodies developed anti-idiotypes until wk 30 of lactation. Total lactation yields were not different among monoclonal antibodies 2, 3, and 4 and control cows (9299, 9321, 9733, and 9415 kg, respectively). However, cows immunized with anti-bST monoclonal antibody 1 had reduced lactation yield compared with cows on other treatments (8136 kg). Daily milk yield of cows immunized with monoclonal antibody 1 was decreased from wk 9 of lactation [36.2 vs. 40.9 kg/d (control)] until the end of lactation, concomitantly with decreased bST concentration from wk 9 of lactation. Cows immunized with anti-bST monoclonal antibody 4 had increased milk yield compared with that of controls during wk 3 to 6 and wk 18 to 21 of lactation. Therefore, anti-idiotypes directed against anti-bST 1 had bST-antagonistic effects on lactation performance; anti-idiotypes against anti-bST 4 transiently increased milk yield.
Roberge
S
S
Department of Animal and Poultry Science, University of Guelph, ON, Canada.
Wilkie
B N
BN
Walton
J S
JS
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000097:blood*; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000494:pharmacology; D002417:Cattle / Q000276:immunology*; D005260:Female; D013006:Growth Hormone / Q000276:immunology*; D007016:Hypophysectomy; D007114:Immunization; D007700:Kinetics; D007774:Lactation / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D013006:Growth Hormone