A vaccine combining two Leishmania braziliensis proteins offers heterologous protection against Leishmania infantum infection

A recombinant chimeric protein composed of human and mice‐specific CD4+ and CD8+ T‐cell epitopes protects against visceral leishmaniasis

“…The spleen of the infected and vaccinated animals was removed, and in vitro cultures were performed as described . The frequency of CD4 + and CD8 + T cells expressing intracytoplasmic cytokines (IFN‐γ, TNF‐α and IL‐10) was determined following a conventional strategy analysis as previously described . The results were expressed as indexes, which were determined by dividing the percentage of CD4 + and CD8 + cytokine‐positive T cells in the stimulated culture, by this observed in the unstimulated control culture (stimulated/unstimulated culture ratio).…”

“…Results were expressed as the log of the titre (ie the dilution corresponding to the last positive well), adjusted per milligram of organ. In addition, the splenic parasite load was evaluated by a q PCR assay, as described …”

Selection strategy of phage-displayed immunogens based on an in vitro evaluation of the Th1 response of PBMCs and their potential use as a vaccine against Leishmania infantum infection

“…The selection strategy used to identify new immunogenic targets based on phage molecules can be considered valid, since these products are not infective or pathogenic to mammalian hosts, but they do replicate inside the host cells, improving the quality and intensity of the generated immune response [ 49 ]. In addition, phage-exposed peptides are robust, stable to harsh conditions and highly immunogenic, and present five copies in each viral particle, in a population of millions of phages, but without interfering in the infectivity of these agents [ 50 – 53 ]. Moreover, the production of the compounds is considered easier and cheaper, when compared to the synthesis of peptides or production of recombinant proteins [ 54 ].…”

The challenges on developing vaccine against visceral leishmaniasis

“…Polyproteins such as KSAC, with sequences from the Leishmania homolog of the receptor for activated C kinase (LACK), glycoprotein 63 kDa (gp63), thiol-specific-antioxidant, hydrophilic acylated surface protein B, sterol 24-c-metlhytransferase, KMP-11, A2 and cysteine proteinase B (CPB) proteins, have been formulated with adjuvants as monophosphoryl lipid A, and shown promising results. Finally, newly identified Leishmania antigens have been selected based on their recognition by sera from symptomatic and asymptomatic dogs using immune proteomic platforms (5) . These antigens have been sequenced and then analyzed in silico resulting in identification of specific cluster of differentiation 4+ (CD4+) and cluster of differentiation 8+ (CD8+) epitopes.…”

“…The concept of formulating cross-protective vaccines based on common antigens in the Leishmania genus and their ability to elicit a particular type of immune response is interesting, but also a challenge. Although partial protection against L. infantum infection has been observed when a Leishmania braziliensis hypothetical protein and eukaryotic initiation factor 5a (EiF5a) were used in conjunction as a polyprotein vaccine in a mouse model (5) , this has yet to be shown in other animals.…”