Persistence of anti-zonae pellucidae antibodies following a single inoculation of porcine zonae pellucidae in the domestic equine

Abstract

In this study of equids, we investigated the antibody response and the effect on the estrous cycle following a single inoculation of porcine zonae pellucidae (pZP) employing controlled-release methodology. We also investigated the use of two different water-soluble adjuvants as an alternative to oil-based adjuvants. Twenty-seven domestic mares were inoculated with various formulations of pZP and adjuvant. We showed that the anti-pZP antibodies generated as a result of the inoculations persisted for at least 43 weeks (length of the study). Of the various formulations used in the study, pZP and QS-21 water-soluble adjuvant, administered in combination with an emulsified preparation of pZP and Freund's Complete Adjuvant generated a significantly (P < 0.05) higher titer of anti-pZP antibodies when compared with other formulations employing the water-soluble adjuvant, Carbopol. Hormone analyses for cyclicity indicated a high incidence and extended duration of persistent corpora lutea among the treated mares. The positive control group of mares receiving two standard inoculations of pZP and Freund's Complete and Incomplete Adjuvants, as well as the placebo group of mares injected with QS-21 only, also exhibited high incidences of persistent corpora lutea. However, all mares eventually returned to normal cyclicity. The basis for the high incidence and extended duration of persistent corpora lutea was unexplained. The results demonstrate for the first time the persistent generation of anti-pZP antibodies following a single inoculation of pZP incorporated into a controlled-released preparation in the horse. This study further suggests that a single inoculation of pZP sequestered in a controlled-release lactide-glycolide polymer may serve as an alternative to traditional two-inoculation protocols for contraception investigations in the equine.

Contraceptive Vaccines for Wildlife: A Review

“…The matrix used thus far has incorporated various ratios of lactide-glycolide, either in the form of microcapsules 81 or in the form of small pellets that can be injected either by hand or by dart. [82][83][84] Results thus far have been encouraging, but not definitive, and a great deal of variability in both the manufacturing process and the results has resulted. Another difficulty with this approach is that it has not been possible to incorporate powerful oil-based adjuvants in the microcapsules and pellets.…”

Phytoestrogen treatment induces testis alterations in dogs. Potential use in population control

“…Their efficacy varies mostly on the general response by the organism rather than on the particular mechanism they are trying to regulate. Antibody-based strategies rely on the response and neutralization equilibrium the immune response allows each time either antigen in active immunization or antibody in passive immunization is boosted (Liu et al 2005). GnRH-based methods are a promising field for reproductive control methods (Herbert and Trigg 2005;Earl et al 2006).…”

“…In females, several oocyte or ZP-based have been the subject of several groups during several years (Serrano and Garcia-Suarez 2001;Srivastava et al 2002). These strategies are not yet fully resolved and at this time are difficult to be applied to free roaming animals (Liu et al 2005).…”

Controlled-release components of PZP contraceptive vaccine extend duration of infertility

“…In vivo assessment should include pretreatment, treatment (contraceptive effect) and followup (return to fertility) data. To date, positive outcomes of in vitro release-delay studies and in vivo titre studies associated with controlled-release pellets have correlated well with fieldtreatment contraceptive success in horses (Turner et al 2002;Liu et al 2005) and deer (Turner et al 1992;Rutberg et al 2004).…”

“…We determined conservation of immunoreactivity by Ochterlony immuno-diffusion and titre response of mares immunised with these PZP preparations. No significant effect on PZP of heat or solvent exposure was observed (Liu et al 2005;Turner et al 2007). …”