Veterinary Research Forum

Abstract Leishmaniasis comprises a spectrum of clinical manifestations caused by protozoan parasites of the genus Leishmania, order Trypanosomatida. Cutaneous leishmaniasis remains a significant zoonotic disease prevalent in tropical and subtropical regions, particularly in developing countries. Despite ongoing research, a definitive cure for this parasitic infection is still needed. This study explored the potential of activatable melittin (AM) as a selective treatment for cutaneous leishmaniasis caused by Leishmania major. The AM was designed using PepFold and ExPASy servers, incorporating a matrix metalloproteinase -2/9 cleavable linker to target L. major-infected macrophages selectively. To enhance drug delivery and reduce potential toxicity, AM was encapsulated within albumin nanoparticles and liposomes. The anti-leishmanial efficacy of these formulations was evaluated at AM concentrations ranging from 25.00 to 100 µg mL^-1 over 48 hr, with each experiment performed in 10 independent replicates (n = 10 per group). Statistical analysis using one-way ANOVA followed by Tukey's post-hoc test revealed a significant reduction in the average number of intracellular amastigotes per macrophage in the liposome-treated and albumin nanoparticle-treated groups (7.00 ± 1.50 amastigotes per macrophage) compared to the untreated infected control group (35.00 ± 3.20 amastigotes per macrophage). Treatment with 25.00 µg mL^-1 of AM encapsulated in non-toxic albumin nanoparticles and liposomes demonstrated the most promising anti-leishmanial effect, resulting in an approximately 80.00% reduction in intracellular L. major amastigotes (compared to control).

Abstract Rhipicephalus (Boophilus) spp. are important vectors for Babesia and Anaplasma species causing severe economic losses in livestock. Chemical compounds are commonly used to control tick infestation; however, acaricides resistance in tick has led to move toward alternative strategies such as vaccination. In this study, we introduced a vaccine candidate, namely CaTro against Rh. microplus tick composing of immunogenic B-cell epitopes derived from Rh. microplus cathepsin L and tropomyosin proteins. To evaluate this vaccine candidate, firstly the CaTro sequence was inserted into the prokaryotic expression vector and the recombinant protein CaTro was expressed in Bl21 bacteria. Afterward, purification was performed by Ni-NTA affinity chromatography. The quality of purified recombinant CaTro was also analyzed using sodium dodecyl sulfate-gel electrophoresis and western blotting. Moreover, to evaluate the induction of immune response, the rabbits were immunized with purified recombinant protein combined with Freund’s adjuvant. The findings of this study revealed molecular weight of expressed protein (CaTro) as 38.00 kDa. Furthermore, anti-CaTro antibody was detected in immunized rabbit's sera through dot blotting; while, there was not any response to the control rabbit's sera. The results suggest that CaTro is a potential candidate to develop an anti- Rh. microplus tick.