Local and systemic effect of transfection-reagent formulated DNA vectors on equine melanoma.
Authors: Mählmann Kathrin, Feige Karsten, Juhls Christiane, Endmann Anne, Schuberth Hans-Joachim, Oswald Detlef, Hellige Mareu, Doherr Marcus, Cavalleri Jessika-M V
Journal: BMC veterinary research
Summary
Grey horses frequently develop melanoma, a challenging condition with limited effective treatments, prompting investigation of DNA vaccination as a potential immunotherapeutic strategy. Researchers vaccinated 27 melanoma-affected grey horses across three groups with intramuscular injections of DNA vectors encoding equine interleukins (IL-12 and IL-18) paired with either human glycoprotein 100, human tyrosinase, or interleukins alone, with one selected tumour receiving additional intradermal peritumoral injection; tumour measurements via callipers and ultrasound and serum antibody responses were tracked across multiple timepoints through day 120. Although the vaccination regimen successfully induced specific serum antibodies against the human melanoma-associated antigens in vaccinated horses, there were no statistically significant differences in melanoma volume reduction between treatment groups or compared to baseline measurements. The findings suggest that whilst xenogenic DNA vaccination can generate an immunological response in equine melanoma patients, this immune activation did not translate into measurable tumour regression under the protocols tested, indicating that alternative vaccination schedules, adjuvant strategies, or combination approaches warrant further investigation before this approach can be recommended for clinical practice.
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Practical Takeaways
- •DNA vaccination shows immunological promise in grey horses with melanoma, potentially offering an alternative to surgical management for this high-incidence condition
- •Combined intramuscular and intradermal injection protocols may provide both systemic and local anti-tumour immunity
- •Antibody response was successfully induced, suggesting the vaccination approach warrants further clinical investigation for efficacy endpoints
Key Findings
- •DNA vector vaccination encoding equine IL-12 and IL-18 with human melanoma-associated antigens (hgp100 or htyr) was administered to 27 grey horses with melanoma across three treatment groups
- •Specific serum antibodies against hgp100 and htyr were successfully generated, demonstrating xenogenic immunological response
- •Intramuscular vaccination combined with intradermal peritumoral injection was evaluated for local and systemic effects on melanoma lesion size