Introducing a new anti-Rhipicephalus (Boophilus) microplus tick recombinant vaccine candidate using cathepsin and tropomyosin multi-epitope gene.

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.

Antimicrobial activity of an antimicrobial peptide against amastigote forms of Leishmania major.

Zoonotic cutaneous leishmaniasis caused by Leishmania major is a most common type of vector-borne disease in Iran. The pentavalent antimonial drugs have been used in the treatment of cutaneous leishmaniasis for a long time, but drug resistance and some of serious side effects have been reported. Thus, discovery and development of new therapeutic candidates are needed. The CM11 peptide is one of these peptides that its anti-bacterial activity has been proven. This peptide is a short cecropin-melittin hybrid peptide obtained through a sequence combination approach. The aim of this study was to evaluate in vitro anti-leishmanial activity of CM11 peptide against amastigote forms of Leishmania major. In this study, amastigote forms of Iranian strain of L. major (MRHO/IR/75/ER) were cultured in the presence of different concentrations of meglumine antimoniate (Glucantime®) to find the most appropriate in vitro concentration of Glucantime® against L. major amastigotes. Then, the anti-leishmanial activities of various concentrations of CM11 peptide (8, 16, 32 and 64 µM) were evaluated for 24, 48 and 72 hr by DAPI staining. In addition, MTT assay was used to determine the cytotoxic effects of CM11 peptide on murine fibroblast cell line. The results showed that CM11 peptide has antimicrobial activity against Iranian isolate of L. major in the laboratory conditions. It seems that the CM11 peptide has significant potential to be used as a new anti-leishmanial agent.