Vaccine potential of LenA and LcpA proteins of Leptospira interrogans in combination with Escherichia coli heat-labile enterotoxin, B subunit (LTB)

Abstract

Background and Objectives: Leptospirosis is a zooanthroponosis caused by the genus of Leptospira. It is an emerging public health problem due to its increasing incidence. The achievement to a vaccine that prevent from entrance of Leptospira interrogans to the deeper tissues of the host is needed. This study aimed to investigate the immunogenicity of LcpA (rLcpA) and LenA (rLenA) recombinant proteins in combination with LTB (rLTB) recombinant protein as an adjuvant against lepto- spiral infection in hamsters.
 Materials and Methods: The genes encoding these proteins were cloned into pGH cloning vector and then lenA, lcpA and ltb genes subcloned into pET-15b and pET-28a expression vectors, respectively. The hamsters were immunized with the puri- fied recombinant proteins and challenged with Leptospira interrogans for evaluation of their survival. The antibody respons- es to the recombinant proteins were determined by ELISA. Then, data entered into SPSS software. Statistical Kruskal–Wallis test was used to compare the significant differences among different groups. The groups with significant differences were further analyzed by post hoc tests. The p value < 0.05 statistically was considered significant.
 Results: Immunized hamsters with rLenA-plus-rLTB, rLcpA-plus-rLTB and rLenA-plus-rLcpA-plus-rLTB proteins showed
 60%, 74%, and 80% survival rates, respectively. A significant amount of interleukin-17 (IL-17), interleukin-4 (IL-4) and gamma interferon (IFNγ) cytokines were produced in immunized hamsters.
 Conclusion: Based on our findings, rLcpA and rLenA proteins in combination with rLTB can protect the hamsters against L. interrogans and effectively induce a protective antibody response. Thus, these proteins can be used as an additional pro- phylactic tool against leptospira.

SARS-COV-2 RBD Oral Vaccine Boosted by Mucosal Immune Adjuvant LTB26 via DCs and B Cells Activation in Mice

“…However, the serum IgG level of LTB34+VP8 vaccination was slightly higher than that of LTB+VP8 treatment, but lower than that of LTB26+VP8 vaccination ( Fig.2A, p<0.01). On the contrary, the serum 6 IgG levels of LTB57+VP8 and LTB85+VP8 vaccinations were lower than that of LTB+VP8 groups ( Fig. 2A).…”

“…However, the toxicity of LT prevented its application in human. In recent years, non-toxic LTB adjuvant had been widely studied 6,9,24,25,26 .…”

“…However, the toxicity of LT prevented its application as adjuvant in human. In recent years, non-toxic LTB adjuvant had been widely used(Cunha, Moreira et al, 2017, Ghazali-Bina et al, 2019, Holmner et al, 2011, Liu, Ma et al, 2016, Ma, Luo et al, 2012). The binding specificity of LTB to GM1 was associated with adjuvant activity.…”

“…Nevertheless, LTB is also not applicable for weaker adjuvanticity comparing with LT. Therefore, the construction of non-toxic 4 LT has been a research hotspot in recent years 4,5,6,7,8 . However, there is little report to develop adjuvanticity-enhanced LTB adjuvant.…”

Human leptospirosis: In search for a better vaccine

“…Furthermore, reverse vaccinology (see below in item ‘Reverse vaccinology’) have revealed new potential vaccine targets like LenA, LcpA and OmpA‐like proteins. A vaccine containing recombinant proteins LenA and LcpA was able to protect 80% of the animals challenged with serovar Copenhageni and induced high IgG titres 144 . In addition, increased plasma levels of IFN‐γ, IL‐4 and IL‐17 were observed, suggesting activation of the cellular immune response 144 …”