Effects of active immunization against a synthetic peptide sequence of the inhibin  -subunit on plasma gonadotrophin concentrations, ovulation rate and lambing rate in ewes

Abstract

Thirty adult Mule (Blue-faced Leicester x Swaledale) ewes were actively immunized against a synthetically produced peptide corresponding to the N-terminus of the alpha-subunit of bovine inhibin conjugated to tuberculin purified protein derivative (PPD). Primary immunization in the late anoestrous period was followed by two booster injections at 5 week intervals. Control groups were either not immunized (n = 15) or received PPD only (n = 15). Ten days after the second booster, oestrus was synchronized using progestagen sponges and ovulation rate was assessed by laparoscopy on days 9-10 of the cycle. Blood samples were taken at the time of each immunization and immediately before laparoscopy. Ewes were mated with fertile rams in mid-November and the resulting conception, pregnancy and lambing rates monitored. All inhibin-immunized ewes generated antibodies that bound 125I-labelled native bovine inhibin (M(r) 32,000), and their plasma follicle-stimulating hormone (FSH) concentrations after the second booster were significantly higher than the preimmunization values (30%; P less than 0.001) and the corresponding value in the controls (25%; P less than 0.025). Inhibin immunization was associated with a 90% increase in ovulation rate (P less than 0.005) and had no adverse effect on conception rate (100%), pregnancy rate (100%) or length of gestation (146 days). However, only a 37% increase (P less than 0.05) in lambing rate was recorded for inhibin-immunized ewes, indicating a higher incidence of wastage of ova, or embryos, or both, in these ewes.(ABSTRACT TRUNCATED AT 250 WORDS)

Ovarian Localization of Immunoglobulin G and Inhibin .ALPHA.-Subunit in Guinea Pigs after Passive Immunization against the Inhibin .ALPHA.-Subunit.

“…Taken together, the findings may indicate that it is very difficult to induce superovulation in guinea pigs by temporarily increasing FSH. Passive immunization against inhibin increases FSH secretion in rats [10,30], hamsters [9], cows [7,8] and ewes [31][32][33] as expected. In contrast, in the present study, passive immunizations against inhibin failed to cause an apparent in increase in the plasma FSH level before ovulation.…”

Effects of active immunization of sheep against an amino terminal peptide of the inhibin alpha C subunit on intrafollicular levels of activin A, inhibin A and follistatin

“…About 1 year earlier, six of the ewes had been actively immunized against a synthetic peptide corresponding to the amino terminal region (amino acids 1-29) of the mature C subunit of bovine inhibin conjugated to tuberculin purified protein derivative (PPD) as described elsewhere (Wrathall et al 1990(Wrathall et al , 1992. At the same time four of the ewes were actively immunized against PPD alone to serve as carrierimmunized controls.…”

“…The existence of such ovarian compensatory mechanisms is also indicated by two studies carried out in this laboratory (Knight et al 1991b, Fray et al 1994) in which we failed to detect raised FSH levels in groups of long-term (>6-month) actively immunized ewes. Previously, the same ewes had shown raised FSH levels during their initial active immunization regimen (see Wrathall et al 1990Wrathall et al , 1992. Such inconsistencies in the FSH response to long-term inhibin immunoneutralization indicate that inhibin antibodies may have additional direct stimulatory effects on follicle development that are independent of changes in FSH secretion.…”

Ovarian Response and Hormonal Profiles in Heifers After Immunization and Re-immunization Against Inhibin .ALPHA.-Subunit.

“…Dev. 48: [599][600][601][602][603][604][605] 2002) t is reported that immunoneutralization of inhibin to induce superovulation provides an alternative to current follicle stimulating hormone (FSH) or equine chorionic gonadotropin (eCG) t r eat m en t pr o t o c o ls fo r t h e pr o d uc t i o n o f transferable embryos in mammals [1][2][3][4][5][6][7][8]. Several studies have shown that active immunization of heifers against inhibin α-subunit [9-13] and passive…”