Gene deleted live attenuated Leishmania vaccine candidates against visceral leishmaniasis elicit pro-inflammatory cytokines response in human PBMCs

Avishek, Kumar; Kaushal, Himanshu; Gannavaram, Sreenivas; Dey, Ranadhir; Selvapandiyan, Angamuthu; Ramesh, V.; Negi, Narender Singh; Dubey, Uma S.; Nakhasi, Hira L.; Salotra, Poonam

doi:10.1038/srep33059

Cited by 31 publications

(25 citation statements)

References 50 publications

(90 reference statements)

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“…The CD200 blocking directed CD200R + T cells to acquire Th1-type functional characteristics that further suggested that reduced CD200-CD200R expression may help antigen experience CD4 + T cells to produce inflammatory cytokines as observed in LdCen −/− -immunized animals. We have previously reported strong protection abilities of these parasites and herein provide one of the possible mechanisms via control of coinhibitory molecules such as CD200 and CD200R, resulting in CD4 + T cells to acquire Th1-type multi-functionality ( 10 – 14 ).…”

Section: Discussionmentioning

confidence: 83%

“…Of the various vaccine formulations tested, live attenuated parasites allow host immune system to interact with a broad repertoire of antigens, which is considered to be essential for the development of protective immunity, and importantly cause no pathology. We have reported on centrin-deleted L. donovani parasites (LdCen −/− ) as live attenuated vaccines in various animal models and in ex vivo human studies ( 10 – 14 ). LdCen −/− parasites induce multiple cytokine (IFNγ, IL-2, and TNFα)-secreting Th1 cells in the immunized mice, a response shown to be the best predictor of protective immunity ( 11 , 12 , 15 ).…”

Section: Introductionmentioning

confidence: 99%

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Centrin-Deleted Leishmania donovani Parasites Help CD4+ T Cells to Acquire Th1 Phenotype and Multi-Functionality Through Downregulation of CD200–CD200R Immune Inhibitory Axis

et al. 2018

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The protozoan parasite Leishmania has evolved several strategies to undermine host defense mechanisms by inducing Th2-type adaptive immunity and suppressing effector functions of Th1 phenotype. In our earlier studies, using centrin gene-deleted Leishmania (LdCen−/−) parasites as an immunogen, we have shown induction of an effective Th1-type immunity and robust memory responses that mediate protection against virulent challenge. However, role of inhibitory signals in Leishmania vaccine induced immunity in general, and LdCen−/− in particular has not been studied. Herein, we report that immunization with LdCen−/− parasites produces more functional Th1-type CD4+ T cells via downregulation of CD200–CD200R immune inhibitory axis compared to wild-type infection. We found that expression of CD200 and CD200R was significantly reduced in LdCen−/− infection compared to wild-type infection. Diminished CD200–CD200R signaling in LdCen−/− infection enabled proliferation of CD4+ T cells and resulted in the induction of pro-inflammatory cytokines and suppression of anti-inflammatory response. The effects of diminished CD200–CD200R signaling by LdCen−/− were most evident in the suppression of IL-10-producing CD4+ T cells that helped enhance more Th1 cytokine producing and multi-functional T cells compared to wild-type infection. In vivo blocking of CD200 expression with anti-CD200 treatment in wild-type infected mice limited Th2 response as indicated by reduction of IL-10-producing Tr1 cells and reduced parasite burden. On the other hand, treatment with anti-CD200 improved the LdCen−/− vaccine-induced multifunctional response and reduction in splenic parasite load upon challenge. Taken together, these studies demonstrate the role of CD200–CD200R signals in the protection induced by LdCen−/− parasites.

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Section: Discussionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Centrin-Deleted Leishmania donovani Parasites Help CD4+ T Cells to Acquire Th1 Phenotype and Multi-Functionality Through Downregulation of CD200–CD200R Immune Inhibitory Axis

et al. 2018

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“…One of these parasite lines with centrin1 gene deletion from a L. donovani strain ( LdCen −/− ) has been characterized extensively ( 15 , 16 , 19 , 20 ) with the LdCen −/− parasites showing 5–8 weeks persistence in mice ( 15 ). Our preclinical evaluations demonstrated the safety, immunogenicity characteristics of LdCen −/− parasites, and protection against infection with virulent L. donovani associated with an induction of a protective adaptive immune response in various animal models including mouse, hamster, and dog ( 15 , 19 , 20 ) and in ex vivo studies in human PBMCs in VL endemic areas ( 21 ).…”

Section: Introductionmentioning

confidence: 82%

Immunization with Live Attenuated Leishmania donovani Centrin−/− Parasites Is Efficacious in Asymptomatic Infection

et al. 2017

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Currently, there is no vaccine against visceral leishmaniasis (VL). Toward developing an effective vaccine, we have reported extensively on the immunogenicity of live attenuated LdCentrin−/− mutants in naive animal models. In VL endemic areas, asymptomatic carriers outnumber symptomatic cases of VL and are considered to be a reservoir of infection. Vaccination of asymptomatic cases represents a viable strategy to eliminate VL. Immunological correlates of protection thus derived might have limited applicability in conditions where the immunized host has prior exposure to virulent infection. To examine whether LdCen−/− parasites can induce protective immunity in experimental hosts that have low-level parasitemia from a previous exposure mimicking an asymptomatic condition, we infected C57Bl/6 mice with wild-type Leishmania donovani parasites expressing LLO epitope (LdWTLLO 103, i.v.). After 3 weeks, the mice with low levels of parasitemia were immunized with LdCen−/− parasites expressing 2W epitope (LdCen−/−2W 3 × 106 i.v.) to characterize the immune responses in the same host. Antigen experienced CD4+ T cells from the asymptomatic (LdWTLLO infected) LdCen−/−2W immunized, and other control groups were enriched using LLO- and 2W-specific tetramers, followed by Flow cytometric analysis. Our analysis showed that comparable CD4+ T cell proliferation and CD4+ memory T cell responses (TCM) represented by CD62Lhi, CCR7+, and IL-7R+ T cell populations were induced with LdCen−/−2W in both asymptomatic and naive animals that received LdCen−/− immunization. Upon restimulation with peptide, TCM cells differentiated into effector T cells and there was no significant difference in the recall response in animals with asymptomatic infection. Following virulent challenge, comparable reduction in splenic parasite burden was observed in both asymptomatic and naive LdCen−/− immunized animals concomitant with the development of multifunctional CD4+ and CD8+ T cells. Further, LdCen−/−2W immunization resulted in complete clearance of the preexisting asymptomatic infection (LdWTLLO). Our results demonstrate that LdCen−/−2W immunization could be efficacious for use in asymptomatic VL individuals. Further, immunization with LdCen−/− could help in reducing the parasite burden in the asymptomatic cases and aid in controlling the VL in endemic areas.

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“…Genetically modified live-attenuated L. donovani Δ Ldcen and Δ Ldp27 has been described as vaccine candidates 10 , 42 , 43 , but also several targets have been implicated in loss of virulence upon disruption in different Leishmania species that often elicit protective immunity in vivo such as: silent information regulator (SIR2) 44 , A2 45 , arabino-1,4-lactone oxidase 9 and biopterin transporter BT1 46 , 47 in L. donovani ; HSP70-II in L. infantum 48 ; mitochondrial superoxide dismutase in L. amazonensis 49 ; δ-amastins in L. braziliensis 50 and cysteine protease B in L. mexicana 51 …”

Section: Discussionmentioning

confidence: 99%

Growth arrested live-attenuated Leishmania infantum KHARON1 null mutants display cytokinesis defect and protective immunity in mice

Santi

Lanza

Tunes

et al. 2018

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There is no safe and efficacious vaccine against human leishmaniasis available and live attenuated vaccines have been used as a prophylactic alternative against the disease. In order to obtain an attenuated Leishmania parasite for vaccine purposes, we generated L. infantum KHARON1 (KH1) null mutants (ΔLikh1). This gene was previously associated with growth defects in L. mexicana. ΔLikh1 was obtained and confirmed by PCR, qPCR and Southern blot. We also generate a KH1 complemented line with the introduction of episomal copies of KH1. Although ΔLikh1 promastigote forms exhibited a growth pattern similar to the wild-type line, they differ in morphology without affecting parasite viability. L. infantum KH1-deficient amastigotes were unable to sustain experimental infection in macrophages, forming multinucleate cells which was confirmed by in vivo attenuation phenotype. The cell cycle analysis of ΔLikh1 amastigotes showed arrested cells at G2/M phase. ΔLikh1-immunized mice presented reduced parasite burden upon challenging with virulent L. infantum, when compared to naïve mice. An effect associated with increased Li SLA-specific IgG serum levels and IL-17 production. Thus, ΔLikh1 parasites present an infective-attenuated phenotype due to a cytokinesis defect, whereas it induces immunity against visceral leishmaniasis in mouse model, being a candidate for antileishmanial vaccine purposes.

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Gene deleted live attenuated Leishmania vaccine candidates against visceral leishmaniasis elicit pro-inflammatory cytokines response in human PBMCs

Cited by 31 publications

References 50 publications

Centrin-Deleted Leishmania donovani Parasites Help CD4+ T Cells to Acquire Th1 Phenotype and Multi-Functionality Through Downregulation of CD200–CD200R Immune Inhibitory Axis

Centrin-Deleted Leishmania donovani Parasites Help CD4+ T Cells to Acquire Th1 Phenotype and Multi-Functionality Through Downregulation of CD200–CD200R Immune Inhibitory Axis

Immunization with Live Attenuated Leishmania donovani Centrin−/− Parasites Is Efficacious in Asymptomatic Infection

Growth arrested live-attenuated Leishmania infantum KHARON1 null mutants display cytokinesis defect and protective immunity in mice

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