Vaccination with L. infantum chagasi Nucleosomal Histones Confers Protection against New World Cutaneous Leishmaniasis Caused by Leishmania braziliensis

Abstract

BackgroundNucleosomal histones are intracellular proteins that are highly conserved among Leishmania species. After parasite destruction or spontaneous lysis, exposure to these proteins elicits a strong host immune response. In the present study, we analyzed the protective capability of Leishmania infantum chagasi nucleosomal histones against L. braziliensis infection using different immunization strategies.Methodology/Principal FindingsBALB/c mice were immunized with either a plasmid DNA cocktail (DNA) containing four Leishmania nucleosomal histones or with the DNA cocktail followed by the corresponding recombinant proteins plus CpG (DNA/Protein). Mice were later challenged with L. braziliensis, in the presence of sand fly saliva. Lesion development, parasite load and the cellular immune response were analyzed five weeks after challenge. Immunization with either DNA alone or with DNA/Protein was able to inhibit lesion development. This finding was highlighted by the absence of infected macrophages in tissue sections. Further, parasite load at the infection site and in the draining lymph nodes was also significantly lower in vaccinated animals. This outcome was associated with increased expression of IFN-γ and down regulation of IL-4 at the infection site.ConclusionThe data presented here demonstrate the potential use of L. infantum chagasi nucleosomal histones as targets for the development of vaccines against infection with L. braziliensis, as shown by the significant inhibition of disease development following a live challenge.

Gene Expression Profile of High IFN-γ Producers Stimulated with Leishmania braziliensis Identifies Genes Associated with Cutaneous Leishmaniasis

“…braziliensis or were cultured in the absence of stimulus (control). RNA was employed in individual quantitative Real Time PCR (qRT-PCR) reactions using primers for IFNG, CXCL10, IFI27, IL6 and IRF1 designed using Primer Express Software (ThermoFisher Scientific), reactions were performed as described elsewhere [10]. qRT- PCRs reactions were run in triplicates for each gene of interest and compared with a housekeeping gene ( GAPDH ), also using the ΔΔCt method [11].…”

Skin vaccination using microneedles coated with a plasmid DNA cocktail encoding nucleosomal histones of Leishmania spp.

“…Leishmania spp. nucleosomal histones elicit interesting immune responses and have been investigated as potential candidate vaccines to prevent leishmaniasis (Carneiro et al, 2012;Carrion et al, 2008b;Iborra et al, 2004). Herein, MN administration of these histones, in the form of a plasmid DNA vaccine, has been explored and may result in a superior immune response compared to conventional i.m., s.c. or i.d.…”

“…The protective efficacy of Leishmania histones administered as a DNA vaccine, either homologous (plasmid DNA only) or heterologous immunization (plasmid DNA + recombinant protein and/or adjuvant) has been previously reported against different species of Leishmania with contradictory results. This homologous vaccine was effective in murine models of CL caused by L. major (Carrion et al, 2008b;Iborra et al, 2004) and L. braziliensis (Carneiro et al, 2012) but it was not able to control infection against VL caused by L. infantum in mice (Carrion et al, 2008a) or hamsters (Pereira et al, 2015). However, Baharia et al found optimum prophylactic efficacy using recombinant histone proteins of L. donovani instead of L. infantum plasmids in those hamsters infected with L. donovani (Baharia et al, 2014).…”

“…This plasmid DNA cocktail resulted in a specific Th1 response with enhanced IFN-γ production and low IL-4 levels, which contributed to control L. major infection in immunized mice (Iborra et al, 2004). Carneiro et al also determined that BALB/c mice immunized with the plasmid DNA mixture expressing four different L. infantum chagasi nucleosomal histones (homologous immunization, DNA/DNA) was as effective as the combination of the DNA cocktail followed by the corresponding recombinant proteins and CpG as an adjuvant (heterologous vaccination, DNA/rprotein+CpG) (Carneiro et al, 2012).…”

Cutaneous Leishmaniasis: Update on Vaccine Development

“…77 Vaccination with DNA-encoding L infantum histone genes H2A, H2B, H3, and H4 also controlled both L major and L braziliensis infections in Balb/C mice. 52,53 Addition of KMP-11 (kinetoplastid membrane protein-11), A2, and HSP70 genes to H2A, H2B, H3, and H4 in the form of HisAK70 DNA vaccine was successful in clearing parasites from the liver in a mouse model of visceral leishmaniasis and resulted in 100% inhibition of parasite visceralization in the CL model. 54 Therefore, the enhanced DNA vaccine provided cross-protection against both CL and visceral leishmaniasis (L major and L infantum).…”