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

Turner, John W.; Rutberg, Allen T.; Naugle, Ricky E.; Kaur, Manpreet; Flanagan, Douglas R.; Bertschinger, H.J.; Liu, Irwin K. M.

doi:10.1071/wr07159

Cited by 28 publications

(18 citation statements)

References 12 publications

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“…Efforts to create longer‐lasting contraceptive vaccines with increased efficacy have involved modifying formulations (Henderson et al , Botha et al ), adjuvants (Allison and Gregoriadis , Gupta et al , Lyda et al ), and delivery matrices (Turner et al , ; Killian et al ). Previous studies have demonstrated a positive correlation between levels of pZP antibodies produced and contraceptive effect via binding of sperm receptor sites (Liu et al , Turner et al ); however, other contraceptive mechanisms of action may involve altered ovarian function.…”

Section: Discussionmentioning

confidence: 99%

“…Mares treated with a 1‐ml injection of 65‐µg pZP in a Freund's complete adjuvant (FCA) emulsion and the simultaneous injection of booster pellets designed to release pZP antigens at 1 month, 3 months, and 12 months had annual reproductive rates for 2001–2004 of 5.9%, 14.0%, 32.0%, and 47.5% compared to an average of 53.8 ± 1.3% for untreated mares (Turner et al ). However, the effectiveness of the slow‐release pellets has been inconsistent (Turner et al , Ransom et al ). SpayVac® (ImmunoVaccine Technologies, Inc. [IVT], Halifax, NS, Canada) is a pZP vaccine that uses a unique liposome technology (DepoVax®) and has delivered single‐dose, long‐lasting immunocontraception in a variety of species including fallow deer ( Dama dama ; Fraker et al ) and gray seals ( Halichoerus grypus ; Brown et al 1997 a ).…”

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confidence: 99%

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Effects of two porcine zona pellucida immunocontraceptive vaccines on ovarian activity in horses

et al. 2013

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Feral horse population growth rates as high as 25% are of concern to those responsible for managing range lands as well as conservation groups. Current methods to control these populations include adoption and long-term holding, which are both costly and controversial. Porcine zona pellucida (pZP) immunocontraception may have the greatest potential to control fertility because it has proven to be effective in other studies and vaccines are easy and safe to administer. One pZP vaccine formulation, SpayVac 1 (ImmunoVaccine Technologies, Inc., Halifax, NS, Canada), has demonstrated single-dose, multi-year contraceptive efficacy in other wildlife species, which would make it both practical and economical for field application. Over a 7-month period during the breeding season, we assessed the effect on ovarian activity of 2 formulations of SpayVac, 1 non-aqueous with modified Freund's adjuvant (MFA) and the other, an aqueous emulsion with MFA, compared to controls (n ¼ 7 per group). Comparative reproductive parameters included serum concentrations of progesterone (P 4 ) determined by enzyme-linked immunosorbent assay (ELISA), ovarian activity assessed by transrectal ultrasound and palpation, as well as gross and histological examination of ovaries upon necropsy (n ¼ 9 or 3 mares from each group) or after ovariectomy (n ¼ 12 or 4 mares from each group). We determined serum antibody titers using ELISA. Mean serum concentrations of P 4 were less in the non-aqueous MFA treatment group compared to control mares (P < 0.025). Ovaries collected from control mares weighed more (P ¼ 0.002) and had greater variation (P ¼ 0.003) than those from either vaccinated group. Both treatment groups also had smaller ovaries and fewer follicles compared to controls (P < 0.001). Three to 4 months after vaccination, 93% of SpayVac-injected mares ceased cycling; whereas all control mares continued to cycle throughout the study. Relatively constant antibody titers were reached by week 6 post-vaccination, although we found appreciable variation within treatment groups, especially 4-8 weeks post-vaccination. Based on our study, the SpayVac formulations impair ovarian function but do not affect other major organ systems, and could provide a safe and effective immunocontraceptive option for mares. Additional research to elucidate the vaccine's mechanism of action, actual contraceptive efficacy, and long-term effects are still needed. Ó 2013 The Wildlife Society.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Effects of two porcine zona pellucida immunocontraceptive vaccines on ovarian activity in horses

et al. 2013

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“…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.…”

Section: Duration Of Contraceptive Actionmentioning

confidence: 99%

Contraceptive Vaccines for Wildlife: A Review

Kirkpatrick¹,

Lyda²,

Frank³

2011

American J Rep Immunol

115

105

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Citation Kirkpatrick JF, Lyda RO, Frank KM. Contraceptive vaccines for wildlife: a review. Am J Reprod Immunol 2011; 66: 40–50 Wildlife, free‐ranging and captive, poses and causes serious population problems not unlike those encountered with human overpopulation. Traditional lethal control programs, however, are not always legal, wise, safe, or publicly acceptable; thus, alternative approaches are necessary. Immunocontraception of free‐ranging wildlife has reached the management level, with success across a large variety of species. Thus far, the immunocontraceptive research and management applications emphasis have been centered on porcine zona pellucida and gonadotropin‐releasing hormone vaccines. Contraceptive success has been achieved in more than 85 different wildlife species, at the level of both the individual animal and the population. At the population management level with free‐ranging species, the primary focus has been on wild horses, urban deer, bison, and African elephants. The challenges in the development and application of vaccine‐based wildlife contraceptives are diverse and include differences in efficacy across species, safety of vaccines during pregnancy, the development of novel delivery systems for wild and wary free‐ranging animals, and the constraints of certain non‐contraceptive effects, such as effects on behavior. Beyond the constraints imposed by the public and a host of regulatory concerns, there exists a real limitation for funding of well‐designed programs that apply this type of fertility control.

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“…The development of a novel, safe and effective adjuvant (AdjuVac, National Wildlife Research Center, Fort Collins, CO, USA) combined with PZP-based vaccine succeeded in rendering animals of several species infertile for several years after a single dose (Table 1). Injectable formulations of PZP vaccines, such as the proprietary liposome-containing product SpayVac (ImmunoVaccine Technologies, Inc., Halifax, NS, Canada), with controlled-release properties, have been developed that generate responses for multiple years following a single administration (Brown et al 1997;Turner et al 2008;Rutberg et al 2013). Modified FCA has also been used as a safe, effective substitute for FCA (Lyda et al 2005).…”

Section: Immunocontraceptive Vaccinesmentioning

confidence: 99%

Fertility control to mitigate human–wildlife conflicts: a review

2014

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Abstract. As human populations grow, conflicts with wildlife increase. Concurrently, concerns about the welfare, safety and environmental impacts of conventional lethal methods of wildlife management restrict the options available for conflict mitigation. In parallel, there is increasing interest in using fertility control to manage wildlife. The present review aimed at analysing trends in research on fertility control for wildlife, illustrating developments in fertility-control technologies and delivery methods of fertility-control agents, summarising the conclusions of empirical and theoretical studies of fertility control applied at the population level and offering criteria to guide decisions regarding the suitability of fertility control to mitigate human-wildlife conflicts. The review highlighted a growing interest in fertility control for wildlife, underpinned by increasing numbers of scientific studies. Most current practical applications of fertility control for wild mammals use injectable single-dose immunocontraceptive vaccines mainly aimed at sterilising females, although many of these vaccines are not yet commercially available. One oral avian contraceptive, nicarbazin, is commercially available in some countries. Potential new methods of remote contraceptive delivery include bacterial ghosts, virus-like particles and genetically modified transmissible and non-transmissible organisms, although none of these have yet progressed to field testing. In parallel, new species-specific delivery systems have been developed. The results of population-level studies of fertility control indicated that this approach may increase survival and affect social and spatial behaviour of treated animals, although the effects are species-and context-specific. The present studies suggested that a substantial initial effort is generally required to reduce population growth if fertility control is the sole wildlife management method. However, several empirical and field studies have demonstrated that fertility control, particularly of isolated populations, can be successfully used to limit population growth and reduce human-wildlife conflicts. In parallel, there is growing recognition of the possible synergy between fertility control and disease vaccination to optimise the maintenance of herd immunity in the management of wildlife diseases. The review provides a decision tree that can be used to determine whether fertility control should be employed to resolve specific human-wildlife conflicts. These criteria encompass public consultation, considerations about animal welfare and feasibility, evaluation of population responses, costs and sustainability.

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

Cited by 28 publications

References 12 publications

Effects of two porcine zona pellucida immunocontraceptive vaccines on ovarian activity in horses

Effects of two porcine zona pellucida immunocontraceptive vaccines on ovarian activity in horses

Contraceptive Vaccines for Wildlife: A Review

Fertility control to mitigate human–wildlife conflicts: a review

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