Lactococcus lactis expressing sand fly PpSP15 salivary protein confers long-term protection against Leishmania major in BALB/c mice

Abstract

Cutaneous leishmaniasisis a vector-borne disease transmitted by Leishmania infected sand flies. PpSP15 is an immunogenic salivary protein from the sand fly Phlebotomus papatasi. Immunization with PpSP15 was shown to protect against Leishmania major infection. Lactococcus lactis is a safe non-pathogenic delivery system that can be used to express antigens in situ. Here, the codon-optimized Ppsp15-egfp gene was cloned in pNZ8121 vector downstream of the PrtP signal peptide that is responsible for expression and secretion of the protein on the cell wall. Expression of PpSP15-EGFP recombinant protein was monitored by immunofluorescence, flow cytometry and Western blot. Also, expression of protein in cell wall compartment was verified using whole cell ELISA, Western blot and TEM microscopy. BALB/c mice were immunized three times with recombinant L. lactis-PpSP15-EGFP cwa , and the immune responses were followed up, at short-term (ST, 2 weeks) and long-term (LT, 6 months) periods. BALB/c mice were challenged with L. major plus P. papatasi Salivary Gland Homogenate. Evaluation of footpad thickness and parasite burden showed a delay in the development of the disease and significantly decreased parasite numbers in PpSP15 vaccinated animals as compared to control group. In addition, immunized mice showed Th1 type immune responses. Importantly, immunization with L. lactis-PpSP15-EGFP cwa stimulated the long-term memory in mice which lasted for at least 6 months. Author summaryDifferent strains of Lactococcus lactis can be used as a suitable non-pathogenic vehicle for live vaccination. In this study, our results demonstrated that recombinant L. lactis could express PpSP15, an immunogenic component of Phlebotomus papatasi saliva, on the cell wall. Furthermore, localizing PpSP15 on the cell wall of L. lactis could trigger short (2 weeks) and long (6 months) memory cellular immunity in BALB/c mice, immunized with the recombinant L. lactis. In addition, after challenging the immunized mice with PLOS Neglected Tropical Diseases | https://doi.

Some Good and Some Bad: Sand Fly Salivary Proteins in the Control of Leishmaniasis and in Autoimmunity

“…Notably, LJL-143 and LJM-17 were proposed as good vaccine candidates against canine Leishmaniasis caused by L. infantum, although an in vivo protective phenotype is yet to be demonstrated (Collin et al, 2009;Abbehusen et al, 2018). Additionally, from the saliva of the closely related P. duboscqui and P. papatasi sand flies, the homologous salivary proteins PpSP15 and PdSP15 (also known as PduM02) protected mice and non-human primates effectively from L. major-induced CL (Oliveira et al, 2008;Oliveira et al, 2015;Davarpanah et al, 2020). Three other proteins from the saliva of P. papatasi, PpSP36 (apyrase), PpSP42, and PpSP44 (both yellow-related proteins) were also proposed as good vaccine candidates for human CL (Tlili et al, 2018); however, efficacy results are either still missing, or contrary to this hypothesis in the case of PpSP44 in mice (Oliveira et al, 2008).…”

“…interferon-g, and IL-12)/low anti-inflammatory (e.g. IL-4, IL-10, TGF-) CD4+ T cell-induced cytokine responses Gomes et al, 2008;Oliveira et al, 2008;Collin et al, 2009;Tavares et al, 2011;Xu et al, 2011;de Moura et al, 2013;Abi Abdallah et al, 2014;Oliveira et al, 2015;Abbehusen et al, 2018;Cunha et al, 2018;Tlili et al, 2018;Gholami et al, 2019;Cecilio et al, 2020;Davarpanah et al, 2020).…”

Plasmid Replicons for the Production of Pharmaceutical-Grade pDNA, Proteins and Antigens by Lactococcus lactis Cell Factories

“…This recombinant strain have a great efficiency in inducing mucosal and systemic immune responses in chicken, against pathogenic avian influenza virus infection. Recently, alternative strategies to display the antigens at the L. lactis surface were developed, such as using a combination of Usp45 and the cA (C terminus of the peptidoglycan-biding domain) domain of the N-Acetyl-muraminidase [ 145 ], the Spax anchoring domain (Lei et al, 2020) or the PrtP signal peptide [ 161 ].…”

A cutting-edge immunoinformatics approach for design of multi-epitope oral vaccine against dreadful human malaria

“…Moreover, L. lactismediated delivery of DNA vaccines also lead to the expression of post-translationally modified antigens by host cells resulting in presentation of conformationally restricted epitopes to the immune system for induction of both cellular and humoral immune responses [112]. Also, with the aforementioned properties, the last two decades witnesses the use of genetically engineered L. lactis system as effective oral based vaccine vehicles for delivering antigens of viruses, bacteria and parasites to elicit both systemic and mucosal immunity [155][156][157][158]. Finally, the size of PV1A and PV3B recombinant DNA (obtained after insertion of cDNA into pIL1 expression vector) was observed as 7477 bp and 8377 bp, respectively which lies inside the ORF and could be translated into respective protein sequences with four additional amino acids (MCKC) at the N-terminus (Fig.…”