Active immunization of beef heifers against luteinizing hormone: III. Evaluation of dose and longevity.
Objectives were to evaluate the dose (Exp. 1) and purity of LH preparations (Exp. 2) on the anti-LH antibody response in heifers. Experiment 3 evaluated the longevity of LH immunization on sterility in heifers. In Exp. 1, 115 crossbred heifers were injected every 3 wk for 6 wk with .1, .33, 1.0, 3.0 or 9.0 mg of LH-ovalbumin. Concentrations of anti-LH antibodies generated were quantified by determining the percentage of binding of [125I]LH in serum. Mena LH binding over wk 0 to 12 was greater in heifers immunized with 1.0 mg conjugate than in heifers immunized with other doses (P less than .05). In Exp. 2, LH-ovalbumin conjugates were made from either LH-1, LH-2 or LH-3, which had relative immunological potencies of 2.1, 1.5 and 1.2 x NIH-LH-S1 units/mg, respectively. Forty-eight crossbred beef heifers were immunized against one of these three LH-ovalbumin conjugates, against LH conjugated without ovalbumin (LH-LH), or against ovalbumin alone (Oval). Estrous cycle activity was monitored by measuring serum progesterone concentration. Potency of the LH preparation used in the LH-ovalbumin conjugate was correlated (r = .94) with its ability to produce LH antibodies. In Exp.3, heifers were injected with 1 mg antigen every 2 wk for 10 wk. Five LH-1 heifers and five control heifers were slaughtered for examination of ovaries 10 wk after the last booster injection. The remaining five LH-I and five control animals were placed with a bull 8 wk after the last booster. All five control heifers conceived by 4 +/- 1 wk after placement with the bull whereas the LH-immunized heifers remained acyclic for 42 to 96 wk.
Grieger
D M
DM
Washington State University, Pullman 99163.
Scarborough
R
R
deAvila
D M
DM
Johnson
H E
HE
Reeves
J J
JJ
D000818:Animals; D000917:Antibody Formation; D002417:Cattle / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D004971:Estrus / Q000276:immunology; D005260:Female; D007114:Immunization / Q000662:veterinary*; D007986:Luteinizing Hormone / Q000008:administration & dosage / Q000276:immunology*; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology*; D011374:Progesterone / Q000097:blood; D011897:Random Allocation; D013245:Sterilization, Reproductive / Q000662:veterinary*
D011374:Progesterone; D007986:Luteinizing Hormone; D010047:Ovalbumin