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Purpose: Evaluation of humoral and cellular immune responses of naturally infected dogs against type I (rCPB) (Recombinant cycsteine proteinase B), and II (rCPA) (Recombinant cycsteine proteinase A) recombinant cysteine proteinases and C-terminal extension (CTE) of Leishmania infantum (L. infantum). Materials and Methods: In this study, fourteen infected dogs (7 with symptoms, 7 asymptomatics) from an endemic area and three uninfected dogs from a nonendemic region were selected and their humoral and cellular responses against type I and II recombinant cysteine proteinases, C-terminal extension (CTE) and F/T of Leishmania infantum were evaluated using the ELISA and lymphocyte proliferation assay, respectively. The level of specific IgG isotypes (IgG1 and IgG2) and lymphocyte proliferative response against rCPA, rCPB, CTE and Freezed/Thawed lysate (F/T) of L. infantum were examined. Results and Discussion: The results showed that in both of the symptomatic and asymptomatic dogs there is a high lymphoproliferative response to F/T antigens and moderate responses were observed when rCPs (Recombinant cycsteine proteinase) (rCPA and rCPB) and CTE were used. The level of antibody (total IgG, IgG1 and IgG2) recognition toward rCPA was low in the both groups of the dogs. In contrast, the CTE stimulates similarly as the CPB both of the humoral and cellular responses of all the infected animals and the level of total IgG and IgG2 isotypes against these antigens compared to the IgG1 was higher in the asymptomatic dogs. Since, the CTE is the terminal fragment of the CPB, it seems that the immunogenicity of the CPB is dependent on the CTE. Conclusion: The results of our investigation indicates that the CPB and CTE stimulate both humoral and cellular immune responses of L. infantum infected dogs, wherase the CPA is a weaker immunogen.

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Aims: One of the challenges of today's world and also global health priorities is pandemicity of AIDS. Studies have shown that the scope and breadth of the immune responses induction are very effective to protect against HIV. Moreover, simultaneous induction of humoral and cellular immunity responses increases the effectiveness of candidate HIV vaccines. Hence, new approaches such as polyepitopic vaccine strategy and addition of different adjuvants in HIV vaccines’ formulations have been recently considered.
Materials and Methods: In the present study, eukaryotic expression vector (pcDNA3.1-tat/pol/gag/env) was transformed and amplified in the prokaryotic host cells E. coli (DH5α). After vector extraction, it was concentrated and formulated alone and in combination with Alum adjuvant and used as DNA candidate vaccines. DNA candidate vaccines were, then, subcutaneously injected to the BALB/c mice on 0, 14, and 28 days and elicited humoral and cellular immunity responses were finally evaluated.
Findings: The results showed that the candidate DNA vaccine could not efficiently induce immunity responses (both humoral and cellular responses) by subcutaneous route injection.
Conclusion: This observation can be due to a defect in each of the steps of vector harvesting by the target cell to express the surface presentation of the epitopes on the one hand, or the inefficiency of the subcutaneous injection method on the other. Therefore, other vaccines’ injection and deliveries routes along with addition of other adjuvants in vaccine’s formulations could induce immunity responses efficiently and increase vaccine efficacy.