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Kammoun-Rebai W, Bahi-Jaber N, Naouar I, Toumi A, Ben Salah A, Louzir H, Meddeb-Garnaoui A. Human cellular and humoral immune responses to Phlebotomus papatasi salivary gland antigens in endemic areas differing in prevalence of Leishmania major infection. PLoS Negl Trop Dis 2017; 11:e0005905. [PMID: 29023574 PMCID: PMC5638224 DOI: 10.1371/journal.pntd.0005905] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 08/24/2017] [Indexed: 01/22/2023] Open
Abstract
Background Sand fly saliva compounds are able to elicit specific immune responses that have a significant role in Leishmania parasite establishment and disease outcome. Characterizing anti-saliva immune responses in individuals living in well defined leishmaniasis endemic areas would provide valuable insights regarding their effect on parasite transmission and establishment in humans. Methodology/Principal findings We explored the cellular and humoral immune responses to Phlebotomus (P.) papatasi salivary gland extracts (SGE) in individuals living in cutaneous leishmaniasis (CL) old or emerging foci (OF, EF). OF was characterized by a higher infection prevalence as assessed by higher proportions of leishmanin skin test (LST) positive individuals compared to EF. Subjects were further subdivided into healed, asymptomatic or naïve groups. We showed anti-SGE proliferation in less than 30% of the individuals, regardless of the immune status, in both foci. IFN-γ production was higher in OF and only observed in immune individuals from OF and naïve subjects from EF. Although IL-10 was not detected, addition of anti-human IL-10 antibodies revealed an increase in proliferation and IFN-γ production only in individuals from OF. The percentage of seropositive individuals was similar in immune and naïves groups but was significantly higher in OF. No correlation was observed between anti-saliva immune responses and LST response. High anti-SGE-IgG responses were associated with an increased risk of developing ZCL. No differences were observed for anti-SGE humoral or cellular responses among naïve individuals who converted or not their LST response or developed or not ZCL after the transmission season. Conclusions/Significance These data suggest that individuals living in an old focus characterized by a frequent exposure to sand fly bites and a high prevalence of infection, develop higher anti-saliva IgG responses and IFN-γ levels and a skew towards a Th2-type cellular response, probably in favor of parasite establishment, compared to those living in an emerging focus. During murine experimental leishmaniasis sand fly saliva components modulate the host immune response and facilitate infection while pre-exposition to uninfected sand fly bites is associated with a protective cellular response against subsequent infection. Human anti-saliva immune responses are not well defined in leishmaniasis endemic areas. Here, we report an analysis of anti P. papatasi saliva cellular and humoral responses in individuals residing in endemic foci showing different prevalence rates of L. major infection. Individuals were further subdivided based on LST response and presence of typical CL scars. We showed higher anti-saliva cellular and humoral responses and a skew towards a Th2 response in the old focus characterized by the highest prevalence of infection. No correlation was observed between LST and anti-saliva cellular or humoral response. We showed that high anti-saliva IgG responses constituted a risk factor for the development of CL. Our findings suggest that the anti-P. papatasi saliva cellular and humoral response profiles vary with the level of sand fly exposure and the prevalence of infection in CL endemic areas. Such studies in humans from highly endemic areas could contribute to a better understanding of the immune response to sand fly saliva and its role in leishmaniasis outcome.
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Affiliation(s)
- Wafa Kammoun-Rebai
- Laboratory of Medical Parasitology, Biotechnologies and Biomolecules, Institut Pasteur de Tunis, Tunis, Tunisia
- Département de Biologie, Université Tunis El Manar, Tunis, Tunisia
| | - Narges Bahi-Jaber
- UPSP EGEAL Institut Polytechnique LaSalle Beauvais, Beauvais, France
| | - Ikbel Naouar
- Département de Biologie, Université Tunis El Manar, Tunis, Tunisia
- Laboratory of Transmission, Control and Immunobiology of Infection, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Amine Toumi
- Laboratory of Transmission, Control and Immunobiology of Infection, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Afif Ben Salah
- Laboratory of Transmission, Control and Immunobiology of Infection, Institut Pasteur de Tunis, Tunis, Tunisia
- Arabian Gulf University, College of Medicine and Medical Sciences, Manama, Bahrain
| | - Hechmi Louzir
- Laboratory of Transmission, Control and Immunobiology of Infection, Institut Pasteur de Tunis, Tunis, Tunisia
- Faculté de Médecine de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Amel Meddeb-Garnaoui
- Laboratory of Medical Parasitology, Biotechnologies and Biomolecules, Institut Pasteur de Tunis, Tunis, Tunisia
- * E-mail:
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Chamakh-Ayari R, Chenik M, Chakroun AS, Bahi-Jaber N, Aoun K, Meddeb-Garnaoui A. Leishmania major large RAB GTPase is highly immunogenic in individuals immune to cutaneous and visceral leishmaniasis. Parasit Vectors 2017; 10:185. [PMID: 28416006 PMCID: PMC5393016 DOI: 10.1186/s13071-017-2127-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 04/04/2017] [Indexed: 12/17/2022] Open
Abstract
Background We previously identified a Leishmania (L.) major large RAB GTPase (LmlRAB), a new atypical RAB GTPase protein. It is highly conserved in Leishmania species while displaying low level of homology with mammalian homologues. Leishmania small RAB GTPases proteins have been involved in regulation of exocytic and endocytic pathways whereas the role of large RAB GTPases proteins has not been characterized yet. We report here the immunogenicity of both recombinant rLmlRAB and rLmlRABC, in individuals with immunity against L. major or L. infantum. Methods PBMC were isolated from individuals cured of L. major (CCLm) or from healthy individuals. The latter were subdivided into high or low IFN-γ responders. Healthy high IFN-γ responders, considered as asymptomatics, were living in an endemic area for L. major (HHRLm) or L. infantum (HHRLi). Healthy low IFN-γ responders (HLR) were considered as naïve controls. Cells from all volunteers were stimulated with rLmlRAB or rLmlRABC. Cytokines were analysed by CBA and ELISA and phenotypes of IFN-γ-producing cells were analysed by flow cytometry. Results Both rLmlRAB and rLmlRABC induced high significant levels of IFN-γ in CCLm, HHRLm and HHRLi groups. Phenotype analysis of rLmlRAB and rLmlRABC-stimulated T cells in CCLm individuals showed a significant increase in the percentage of specific IFN-γ-producing CD4+ and CD8+ T cells. rLmlRAB induced significant granzyme B levels in CCLm and HHRLm. Low but significant granzyme B levels were detected in naïve group. IL-10 was detected in immune and naïve individuals. Conclusion We showed that rLmlRAB protein and its divergent carboxy-terminal part induced a predominant Th1 response in individuals immune to L. major or L. infantum. Our results suggest that rLmlRAB and rLmlRABC proteins are potential cross-species vaccine candidates against cutaneous and visceral leishmaniasis.
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Affiliation(s)
- Rym Chamakh-Ayari
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Institut Pasteur de Tunis, Tunis, Tunisia.,University of Carthage, Tunis, Tunisia
| | - Mehdi Chenik
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Ahmed Sahbi Chakroun
- Molecular Epidemiology and Experimental Pathology Applied to Infectious Diseases Laboratory, Institut Pasteur de Tunis, Tunis, Tunisia
| | | | - Karim Aoun
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Amel Meddeb-Garnaoui
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Institut Pasteur de Tunis, Tunis, Tunisia.
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Naouar I, Boussoffara T, Chenik M, Gritli S, Ben Ahmed M, Belhadj Hmida N, Bahi-Jaber N, Bardi R, Gorgi Y, Ben Salah A, Louzir H. Prediction of T Cell Epitopes from Leishmania major Potentially Excreted/Secreted Proteins Inducing Granzyme B Production. PLoS One 2016; 11:e0147076. [PMID: 26771180 PMCID: PMC4714855 DOI: 10.1371/journal.pone.0147076] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 12/27/2015] [Indexed: 01/05/2023] Open
Abstract
Leishmania-specific cytotoxic T cell response is part of the acquired immune response developed against the parasite and contributes to resistance to reinfection. Herein, we have used an immune-informatic approach for the identification, among Leishmania major potentially excreted/secreted proteins previously described, those generating peptides that could be targeted by the cytotoxic immune response. Seventy-eight nonameric peptides that are predicted to be loaded by HLA-A*0201 molecule were generated and their binding capacity to HLA-A2 was evaluated. These peptides were grouped into 20 pools and their immunogenicity was evaluated by in vitro stimulation of peripheral blood mononuclear cells from HLA-A2+-immune individuals with a history of zoonotic cutaneous leishmaniasis. Six peptides were identified according to their ability to elicit production of granzyme B. Furthermore, among these peptides 3 showed highest affinity to HLA-A*0201, one derived from an elongation factor 1-alpha and two from an unknown protein. These proteins could constitute potential vaccine candidates against leishmaniasis.
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Affiliation(s)
- Ikbel Naouar
- Laboratory of Transmission, Control, and Immunobiology of Infections-LR11IPT02, Pasteur Institute of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
| | - Thouraya Boussoffara
- Laboratory of Transmission, Control, and Immunobiology of Infections-LR11IPT02, Pasteur Institute of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
- * E-mail:
| | - Mehdi Chenik
- University of Tunis El Manar, Tunis, Tunisia
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Pasteur Institute of Tunis, Tunis, Tunisia
| | - Sami Gritli
- Department of Pathology, Charles Nicolle Hospital and Faculty of Medicine of Tunis, Tunis, Tunisia
| | - Melika Ben Ahmed
- Laboratory of Transmission, Control, and Immunobiology of Infections-LR11IPT02, Pasteur Institute of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
| | - Nabil Belhadj Hmida
- Laboratory of Transmission, Control, and Immunobiology of Infections-LR11IPT02, Pasteur Institute of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
| | - Narges Bahi-Jaber
- Laboratory of Transmission, Control, and Immunobiology of Infections-LR11IPT02, Pasteur Institute of Tunis, Tunis, Tunisia
- UPSP EGEAL Institut Polytechnique LaSalle Beauvais, Beauvais, France
| | - Rafika Bardi
- Laboratory of Immunology, Charles Nicolle Hospital, Tunis, Tunisia
| | - Yousr Gorgi
- Laboratory of Immunology, Charles Nicolle Hospital, Tunis, Tunisia
| | - Afif Ben Salah
- Laboratory of Transmission, Control, and Immunobiology of Infections-LR11IPT02, Pasteur Institute of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
| | - Hechmi Louzir
- Laboratory of Transmission, Control, and Immunobiology of Infections-LR11IPT02, Pasteur Institute of Tunis, Tunis, Tunisia
- University of Tunis El Manar, Tunis, Tunisia
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Elmhiri G, Hamoudi D, Dou S, Bahi-Jaber N, Reygnier J, Larcher T, Firmin S, Abdennebi-Najar L. Antioxidant properties of formula derived Maillard reaction products in colons of intrauterine growth restricted pigs. Food Funct 2016; 7:2582-90. [DOI: 10.1039/c5fo01551k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The present study has been conducted to evaluate the impact of the consumption of high MRP formula on changes in the microbiota and oxidative stress in the colon of IUGR piglets.
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Affiliation(s)
- Ghada Elmhiri
- UP-EGEAL 2012.10.101 Institut Polytechnique LaSalle Beauvais
- Beauvais Cedex
- France
| | - Dounia Hamoudi
- UP-EGEAL 2012.10.101 Institut Polytechnique LaSalle Beauvais
- Beauvais Cedex
- France
| | - Samir Dou
- UP-EGEAL 2012.10.101 Institut Polytechnique LaSalle Beauvais
- Beauvais Cedex
- France
| | - Narges Bahi-Jaber
- UP-EGEAL 2012.10.101 Institut Polytechnique LaSalle Beauvais
- Beauvais Cedex
- France
| | - Julie Reygnier
- UP-EGEAL 2012.10.101 Institut Polytechnique LaSalle Beauvais
- Beauvais Cedex
- France
- Laboratoire Périnatalité et Risques Toxiques (PERITOX)
- UMR-I01 INERIS
| | - Thibaut Larcher
- INRA
- UMR 703 APEX
- Ecole Nationale Vétérinaire Agroalimentaire et de l'Alimentation Nantes-Atlantique (Oniris)
- Nantes
- France
| | - Stéphane Firmin
- UP-EGEAL 2012.10.101 Institut Polytechnique LaSalle Beauvais
- Beauvais Cedex
- France
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Markikou-Ouni W, Drini S, Bahi-Jaber N, Chenik M, Meddeb-Garnaoui A. Immunomodulatory Effects of Four Leishmania infantum Potentially Excreted/Secreted Proteins on Human Dendritic Cells Differentiation and Maturation. PLoS One 2015; 10:e0143063. [PMID: 26581100 PMCID: PMC4651425 DOI: 10.1371/journal.pone.0143063] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 10/07/2015] [Indexed: 11/18/2022] Open
Abstract
Leishmania parasites and some molecules they secrete are known to modulate innate immune responses through effects on dendritic cells (DCs) and macrophages. Here, we characterized four Leishmania infantum potentially excreted/secreted recombinant proteins (LipESP) identified in our laboratory: Elongation Factor 1 alpha (LiEF-1α), a proteasome regulatory ATPase (LiAAA-ATPase) and two novel proteins with unknown functions, which we termed LiP15 and LiP23, by investigating their effect on in vitro differentiation and maturation of human DCs and on cytokine production by DCs and monocytes. During DCs differentiation, LipESP led to a significant decrease in CD1a. LiP23 and LiEF-1α, induced a decrease of HLA-DR and an increase of CD86 surface expression, respectively. During maturation, an up-regulation of HLA-DR and CD80 was found in response to LiP15, LiP23 and LiAAA-ATPase, while an increase of CD40 expression was only observed in response to LiP15. All LipESP induced an over-expression of CD86 with significant differences between proteins. These proteins also induced significant IL-12p70 levels in immature DCs but not in monocytes. The LipESP-induced IL-12p70 production was significantly enhanced by a co-treatment with IFN-γ in both cell populations. TNF-α and IL-10 were induced in DCs and monocytes with higher levels observed for LiP15 and LiAAA-ATPase. However, LPS-induced cytokine production during DC maturation or in monocyte cultures was significantly down regulated by LipESP co-treatment. Our findings suggest that LipESP strongly interfere with DCs differentiation suggesting a possible involvement in mechanisms established by the parasite for its survival. These proteins also induce DCs maturation by up-regulating several costimulatory molecules and by inducing the production of proinflammatory cytokines, which is a prerequisite for T cell activation. However, the reduced ability of LipESP-stimulated DCs and monocytes to respond to lipopolysaccharide (LPS) that can be observed during human leishmaniasis, suggests that under certain circumstances LipESP may play a role in disease progression.
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Affiliation(s)
- Wafa Markikou-Ouni
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Sima Drini
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, Institut Pasteur de Tunis, Tunis, Tunisia
- Unité de Parasitologie moléculaire et Signalisation, Institut Pasteur, Paris, France
| | - Narges Bahi-Jaber
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, Institut Pasteur de Tunis, Tunis, Tunisia
- UPSP EGEAL Institut Polytechnique LaSalle Beauvais, Beauvais, France
| | - Mehdi Chenik
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Amel Meddeb-Garnaoui
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, Institut Pasteur de Tunis, Tunis, Tunisia
- * E-mail:
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Chamakh-Ayari R, Bras-Gonçalves R, Bahi-Jaber N, Petitdidier E, Markikou-Ouni W, Aoun K, Moreno J, Carrillo E, Salotra P, Kaushal H, Negi NS, Arevalo J, Falconi-Agapito F, Privat A, Cruz M, Pagniez J, Papierok GM, Rhouma FBH, Torres P, Lemesre JL, Chenik M, Meddeb-Garnaoui A. In vitro evaluation of a soluble Leishmania promastigote surface antigen as a potential vaccine candidate against human leishmaniasis. PLoS One 2014; 9:e92708. [PMID: 24786587 PMCID: PMC4008367 DOI: 10.1371/journal.pone.0092708] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 02/24/2014] [Indexed: 12/31/2022] Open
Abstract
PSA (Promastigote Surface Antigen) belongs to a family of membrane-bound and secreted proteins present in several Leishmania (L.) species. PSA is recognized by human Th1 cells and provides a high degree of protection in vaccinated mice. We evaluated humoral and cellular immune responses induced by a L. amazonensis PSA protein (LaPSA-38S) produced in a L. tarentolae expression system. This was done in individuals cured of cutaneous leishmaniasis due to L. major (CCLm) or L. braziliensis (CCLb) or visceral leishmaniasis due to L. donovani (CVLd) and in healthy individuals. Healthy individuals were subdivided into immune (HHR-Lm and HHR-Li: Healthy High Responders living in an endemic area for L. major or L. infantum infection) or non immune/naive individuals (HLR: Healthy Low Responders), depending on whether they produce high or low levels of IFN-γ in response to Leishmania soluble antigen. Low levels of total IgG antibodies to LaPSA-38S were detected in sera from the studied groups. Interestingly, LaPSA-38S induced specific and significant levels of IFN-γ, granzyme B and IL-10 in CCLm, HHR-Lm and HHR-Li groups, with HHR-Li group producing TNF-α in more. No significant cytokine response was observed in individuals immune to L. braziliensis or L. donovani infection. Phenotypic analysis showed a significant increase in CD4+ T cells producing IFN-γ after LaPSA-38S stimulation, in CCLm. A high positive correlation was observed between the percentage of IFN-γ-producing CD4+ T cells and the released IFN-γ. We showed that the LaPSA-38S protein was able to induce a mixed Th1 and Th2/Treg cytokine response in individuals with immunity to L. major or L. infantum infection indicating that it may be exploited as a vaccine candidate. We also showed, to our knowledge for the first time, the capacity of Leishmania PSA protein to induce granzyme B production in humans with immunity to L. major and L. infantum infection.
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Affiliation(s)
- Rym Chamakh-Ayari
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Rachel Bras-Gonçalves
- Institut de Recherche pour le Développement, UMR177 IRD/CIRAD «INTERTRYP», Montpellier, France
| | - Narges Bahi-Jaber
- Laboratory of Transmission, Control and Immunobiology of Infection, LR11-IPT-02, Institut Pasteur de Tunis, Tunis, Tunisie
- UPSP EGEAL Institut Polytechnique LaSalle Beauvais, Beauvais, France
| | - Elodie Petitdidier
- Institut de Recherche pour le Développement, UMR177 IRD/CIRAD «INTERTRYP», Montpellier, France
| | - Wafa Markikou-Ouni
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Karim Aoun
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Javier Moreno
- WHO Collaborating Center for Leishmaniasis, Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Madrid, Spain
| | - Eugenia Carrillo
- WHO Collaborating Center for Leishmaniasis, Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Madrid, Spain
| | - Poonam Salotra
- National Institute of Pathology (ICMR), Safdarjung Hospital Campus, New Delhi, India
| | - Himanshu Kaushal
- National Institute of Pathology (ICMR), Safdarjung Hospital Campus, New Delhi, India
| | - Narender Singh Negi
- National Institute of Pathology (ICMR), Safdarjung Hospital Campus, New Delhi, India
| | - Jorge Arevalo
- Instituto de Medicina Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Francesca Falconi-Agapito
- Instituto de Medicina Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Angela Privat
- Instituto de Medicina Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Maria Cruz
- Instituto de Medicina Tropical “Alexander von Humboldt”, Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Julie Pagniez
- Institut de Recherche pour le Développement, UMR177 IRD/CIRAD «INTERTRYP», Montpellier, France
| | | | - Faten Bel Haj Rhouma
- Laboratory of Transmission, Control and Immunobiology of Infection, LR11-IPT-02, Institut Pasteur de Tunis, Tunis, Tunisie
| | - Pilar Torres
- Centro de Transfusión de la Comunidad de Madrid, Madrid, Spain
| | - Jean-Loup Lemesre
- Institut de Recherche pour le Développement, UMR177 IRD/CIRAD «INTERTRYP», Montpellier, France
| | - Mehdi Chenik
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Institut Pasteur de Tunis, Tunis, Tunisia
| | - Amel Meddeb-Garnaoui
- Laboratory of Medical Parasitology, Biotechnology and Biomolecules, LR11-IPT-06, Institut Pasteur de Tunis, Tunis, Tunisia
- * E-mail:
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Pontier D, Fouchet D, Bahi-Jaber N, Poulet H, Guiserix M, Natoli E, Sauvage F. When domestic cat (Felis silvestris catus) population structures interact with their viruses. C R Biol 2008; 332:321-8. [PMID: 19281962 PMCID: PMC7185750 DOI: 10.1016/j.crvi.2008.07.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 07/21/2008] [Indexed: 12/11/2022]
Abstract
Many theoretical studies have proposed different causal mechanisms by which the structure of a host population could have important implications for life history traits of pathogens. However, little information is available from real systems to test these hypotheses. The domestic cat, Felis silvestris catus, whose populations exhibit a great variability in social and spatial structure, represent an ideal case study to assess this question. In the present article, we show how cat population structure may have influenced the evolution of feline viruses and, in return, how these viruses may have modified the genetic structure of cat populations. To cite this article: D. Pontier et al., C. R. Biologies 332 (2009).
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Affiliation(s)
- Dominique Pontier
- Université de Lyon, Université Lyon 1, CNRS, UMR 5558, Laboratoire de Biométrie et Biologie Evolutive, 69622 Villeurbanne, France.
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Abstract
Stochastic fluctuations in the transmission process of microparasites generate a risk of parasite extinction that cannot be assessed by deterministic models, especially in host populations of small size. While this risk of extinction represents a strong selection pressure for microparasites, it is usually not clearly separated from the deterministic ones. We suggest here that this stochastic selection pressure can affect the selection of the transmission mode of microparasites. To avoid extinction, parasites should maximize their inter-population transmission to ensure frequent reintroductions. Since the types of contacts may differ if congeners belong to the same or distinct populations, strains that are mainly transmitted through inter-population contacts might be selected. To examine this assumption, we analyse the issue of the competition between two strains differing in their transmission mode using a stochastic metapopulation model in which hosts may display different behaviours inside and outside their populations. We show that stochastic selection pressures may drive parasite evolution towards a transmission mode that maximizes the persistence of the parasite. We study the conditions under which stochastic selection pressures may surpass the deterministic ones. Our results are illustrated by the cases of feline immunodeficiency virus in cats and of sexually transmitted diseases in mammals.
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Affiliation(s)
- Narges Bahi-Jaber
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), CNRS, Université de Lyon, Université Lyon 1, 43 boulevard 11 novembre 1918, 69622 Villeurbanne Cedex, France.
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Guiserix M, Bahi-Jaber N, Fouchet D, Sauvage F, Pontier D. The canine distemper epidemic in Serengeti: are lions victims of a new highly virulent canine distemper virus strain, or is pathogen circulation stochasticity to blame? J R Soc Interface 2007; 4:1127-34. [PMID: 17456450 PMCID: PMC2396208 DOI: 10.1098/rsif.2007.0235] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2007] [Accepted: 03/20/2007] [Indexed: 11/12/2022] Open
Abstract
In the year 1994, the Serengeti lion population was decimated by a canine distemper disease outbreak. Retrospective investigations showed that this host population had already been in contact with the pathogen in 1981 without any detected sign of disease. As an alternative to the virus mutation hypothesis to explain this difference in virulences observed in 1981 and 1994, we propose a novel mechanism of disease emergence based on variation in population immunity. We use a stochastic model to show that stochastic fluctuations in pathogen circulation, owing to a low probability of virus transmission from its reservoir to the target host and thereby resulting in variations in the global immunity level of the target host population, can explain the observations made in Serengeti. This mechanism may also be involved in other infectious disease emergences or re-emergences.
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Affiliation(s)
- Micheline Guiserix
- Laboratoire de Biométrie et Biologie Evolutive, CNRS, UMR 5558, Université de Lyon, Université Lyon 1, Villeurbanne, France.
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Ouakad M, Bahi-Jaber N, Chenik M, Dellagi K, Louzir H. Selection of endogenous reference genes for gene expression analysis in Leishmania major developmental stages. Parasitol Res 2007; 101:473-7. [PMID: 17318579 DOI: 10.1007/s00436-007-0491-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2006] [Accepted: 02/01/2007] [Indexed: 10/23/2022]
Abstract
At the era of post-genomics, gene expression analysis constitutes an important step for understanding the biological functions of genes. For this, reverse transcription and real-time polymerase chain reaction (RT-PCR) is one of the most accurate techniques available to date. Normalization with a proper internal control is critical for the generation of reliable results with biological significance. This is particularly true for pathogens, like Leishmania (L.) parasites, that alternate between different stages during their life cycle. In this study, we evaluate six different sequences for their potential as suitable internal control for the study of gene expression in three different developmental stages (procyclic and metacyclic promastigotes and amastigotes) of the parasite Leishmania major. Experiments were performed on RNA purified from three L. major isolates using the RT-PCR technique. Data analysis was performed using GeNorm and NormFinder programs. We could determine that a sequence encoding rRNA45 is the most stable in the three developmental stages of the parasite and can thus be used as a reference gene in gene expression studies in L. major.
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Affiliation(s)
- Meriam Ouakad
- Laboratory of Immunopathology, Vaccinology and Molecular Genetics (LIVGM), Institut Pasteur de Tunis, BP 74, 13, Place Pasteur, 1002, Tunis-Belvedere, Tunisia
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Abstract
In order to improve our understanding of directly transmitted pathogens within host populations, epidemic models should take into account individual heterogeneities as well as stochastic fluctuations in individual parameters. The associated cost results in an increasing level of complexity of the mathematical models which generally lack consistent formalisms. In this paper, we demonstrate that complex epidemic models could be expressed as colored stochastic Petri nets (CSPN). CSPN is a mathematical tool developed in computer science. The concept is based on the Markov Chain theory and on a standard well codified graphical formalism. This approach presents an alternative to other computer simulation methods since it offers both a theoretical formalism and a graphical representation that facilitate the implementation, the understanding and thus the replication or modification of the model. We explain how common concepts of epidemic models--such as the incidence function--can be easily translated into an individual based point of view in the CSPN formalism. We then illustrate this approach by using the well documented susceptible-infected model with recruitment and death.
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Affiliation(s)
- Narges Bahi-Jaber
- UMR C.N.R.S. 5558 Biométrie et Biologie Evolutive, Université Claude Bernard Lyon-1, 43 Boul. 11 Novembre 1918, 69622 Villeurbanne Cedex, France.
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12
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Abstract
A new theoretical approach is proposed to investigate the effect of intra-individual variability in behavior on the spread of directly transmitted diseases within host populations. The classical hawk-dove game is used to describe interactions between individuals on a fast time scale (the day). Individuals may exhibit both tactics according to their own experience, to environment conditions, and to the opponent. They are not able to recognize the epidemiological state of their opponents. This fast-time part of the model is coupled to a classical compartmental epidemic model describing the demography of the population and the transmission of the disease from an infected individual to a healthy one on a slow time scale (the year). The model is applied to the case of feline immunodeficiency virus (FIV)-domestic cat population system. Our model gives rise to different predictions according to values of cost and gain due to fights: extinction of the epidemic, FIV endemicity at low, intermediate and high prevalence. These predictions are in good agreement with results from domestic cat populations living in different environmental conditions.
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Affiliation(s)
- Narges Bahi-Jaber
- Biométrie et Biologie Evolutive, UMR CNRS 5558, Université Claude Bernard Lyon 1, 43 boulevard du 11 Novembre 1918, FR-69622, Cédex, Villeurbanne, France.
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