There are many strategies to control leishmaniasis, but majority of them are inadequate. Killed Leishmania vaccine (KLV) has been applied for its immunogenicity in human and mouse model. Bacillus Calmette-Guerin (BCG) as adjuvant is an immunemodulator inducing humoral and cellular immune responses during zoonotic cutaneous leishmaniasis (ZCL). Both KLV and BCG have been applied for their immune responses in hosts for controlling leishmaniasis. In this study, KLV and BCG were applied to inhibit replication and visceralization of Leishmania major in BALB/c mice. Mice were injected with KLV and BCG, followed by infection with promastigotes of L. major. Six weeks after infection, a small nodule appeared, which was followed by development of a large lesion and visceralization. Effects of KLV and BCG, physiopathological changes, lesion size, delay of lesion formation, proliferation of amastigotes inside macrophages and detection of amastigotes in target organs were studied. Results showed that the KLV had anti-leishmanial activity by reducing lesion size on late infection. In KLV and BCG group, the average number of amastigotes in macrophages was lower than in other groups. Significant reductions in number of amastigotes in both spleen and lymph node were observed, indicating lower visceralization of Leishmania parasites in these target organs. No significant changes were presented in body weights, survival rates and degrees of splenomegaly in test group. It can be concluded that application of KLV and BCG had acceptable efficacy in reduction of skin lesions size and proliferation of parasites, even though a few side-effects were observed. It is indicated that KLV/BSG may have ability to modulate host immune responses against Leishmania parasites and to reduce pathophysiology of the disease during infection.
Apical membrane antigen-1 (AMA-1) of Plasmodium vivax Grassi et Feletti, 1890 is a promising malaria vaccine candidate. However, antigenic variation is a major problem to design a universal malaria vaccine. Hence, detailed understanding of the pvama-1 gene polymorphism can provide conductive information on this potential vaccine component. Therefore, this study investigated the extent of genetic polymorphisms at domain I (DI), DII and partial DIII of AMA-1 among Iranian P. vivax isolates. Out of 107 blood samples, 92 were analysed based on the quality of the sequencing data. The sequences were classified into 53 haplotypes. Amino acid changes were observed at 31 positions that 17 were located at DI, 11 were at DII and the rest of them (3 positions) were at DIII. Thus, codon polymorphisms at DI were found to be higher than DII. Also, five of these polymorphic codons (D242E, T374P, S389R, Y391F, I395F) were novel and have not been reported yet. Neutrality analysis by using the dN-dS difference (the difference between the rate of non-synonymous and synonymous mutations) showed a negative diversifying selection at DI, DII and across the length of both domains. The potential B-cell epitopes were found in 5 regions of the PvAMA-1 with 10 mutation sites (E145A, K188N, E189N/K/D, K190Q/E, P210S, E227V, D242E, R249H, G253E, K352E), whereas only one mutation (G288E) has been detected in intrinsically unstructured/disordered regions. Fixation index (Fst) estimation between Iranian and Indian isolates (0.0131) indicated a significant low genetic differentiation. Distribution of the polymorphic sites and IURs mapped on a three dimensional structure of PvAMA-1 showed that these regions were located at two opposite faces of the molecule. In conclusion, the results have significant value in the design and development of a malaria vaccine based on this antigen.