Infectivity of the Subspecies of the Leishmania braziliensis Complex in Vivo and in Vitro

Rey, Jean-Loup; Travi, Bruno L.; Valencia, Anais Zully; Saravia, Nancy Gore

doi:10.4269/ajtmh.1990.43.623

Cited by 42 publications

(39 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…infectivity in BALB/c mice and hamsters is very variable and unpredictable by comparison with other species. 39,40 Several reports have documented macrophage-like cell line in vitro infection as being an alternate model for conversion from promastigote to amastigote stage. 41,42 The U937 cell line has been extensively used for parasite differentiation, replication, and maturation studies.…”

Section: Discussionmentioning

confidence: 99%

Cultivation and characterization of stable Leishmania guyanensis complex axenic amastigotes derived from infected U937 cells.

Puentes¹,

Díaz²,

Hoya³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

View full text Add to dashboard Cite

Abstract. The study of the differential regulation of several genes, in both Leishmania parasite life cycle forms, has been simplified by the development of in vitro axenic amastigote culture. Different reports have described extracellular amastigote production and maintenance from several Leishmania spp. A general approach to induce amastigote-like transformation includes progressive pH and temperature changes. Production of axenic amastigotes in continuous cultures using amastigotes recovered from macrophages is described in this report. Leishmania (Viannia) panamensis (M/HOM/PA/71/LS94) and Leishmania (V). guyanensis (M/HOM/BR/75/M4147) intracellular amastigotes were recovered from the human macrophage-like U937 cell line previously infected with promastigotes. The parasites were immediately adapted for growth and kept as axenic amastigotes at 34ЊC and acidic pH. These organisms were able to infect macrophage cell lines, maintain amastigote morphologic features, and express stage-specific transcripts. The relevance of axenic amastigotes in characterizing virulence factors in American leishmaniasis is discussed.

show abstract

Section: Discussionmentioning

confidence: 99%

Cultivation and characterization of stable Leishmania guyanensis complex axenic amastigotes derived from infected U937 cells.

Puentes¹,

Díaz²,

Hoya³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

View full text Add to dashboard Cite

show abstract

“…The U937 cell line has been successfully used as model for infection with macrophage-specific pathogens as diverse as Leishmania [17][18][19], Brucella, and Listeria [20] or Salmonella [21] species and thus represents a valuable model to study human macrophage-pathogen interactions. To support infection by Leishmania, U937 cells have been differentiated into M -like cells by using phorbol myristate acetate [17,18,22], a molecule that triggers a large panel of intracellular events associated with protein kinase C activation.…”

Section: Discussionmentioning

confidence: 99%

“…To support infection by Leishmania, U937 cells have been differentiated into M -like cells by using phorbol myristate acetate [17,18,22], a molecule that triggers a large panel of intracellular events associated with protein kinase C activation. In this study, we applied for U937 cell differentiation a procedure first used to promote infection by bacteria [20].…”

Section: Discussionmentioning

confidence: 99%

Human monocytic U937 cells transfected with human hepatic inducible nitric oxide synthase exhibit leishmanicidal activity

Bertholet

Mauël

2000

Journal of Leukocyte Biology

View full text Add to dashboard Cite

“…Recientemente, Spath y Beverly (15) diseñaron un método de separación de formas metacíclicas, independiente de LPG, el cual mostró buena eficacia y correlación con el método basado en aglutinación con PNA; sin embargo, su utilidad práctica en otras especies diferentes a L. major aún no se ha evaluado. La transformación hacia una forma más infectiva in vitro es evidente o está bien documentada en especies de Leishmania del Viejo Mundo; sin embargo, no parece existir una infectividad estrictamente dependiente de la fase de crecimiento en cepas de Leishmania del subgénero Viannia (16).…”

Section: Evidencias De Un Estadio Infectivo En Promastigotes De Leishunclassified

“…Al menos, cinco formas se han descrito en el vector durante el desarrollo del parásito Leishmania (subgénero Leishmania): promastigotes procíclicos, nectomónadas, haptomónadas, paramastigotes y, finalmente, promastigotes metacíclicos (19). Las formas metacíclicas tienden a ser más pequeñas, delgadas y con un flagelo más largo, presentan alta movilidad y migran hacia la parte anterior del tracto digestivo ubicándose a la altura de la probóscide (16,19). Como promastigotes metacíclicos, están listos para ser inoculados en el hospedero mamífero ante una nueva ingestión de sangre por el vector (7,19).…”

Section: Cambios Morfológicos Genéticos Y Bioquímicos Asociados Con unclassified

Metaciclogénesis: un proceso fundamental en la biología de Leishmania

Muskus¹,

Marín-Villa²

2002

biomedica

View full text Add to dashboard Cite

La metaciclogénesis es un proceso que experimentan naturalmente los promastigotes de Leishmania en el tracto digestivo del insecto vector y cuya finalidad es transformar los promastigotes en formas altamente infectivas y capaces de sobrevivir en el hospedero vertebrado, donde es sometido a los ataques por parte del sistema inmune. Se ha demostrado que este fenómeno ocurre también en promastigotes en crecimiento en cultivos axénicos in vitro. El proceso de metaciclogénesis se asoció inicialmente con cambios morfológicos, observándose que los promastigotes cambiaban su forma y tamaño con incremento en la longitud del flagelo. Luego, se logró asociar con este fenómeno la expresión de ciertas moléculas implicadas en virulencia, como el lipofosfoglicano (LPG) y una proteasa de superficie, la gp63. Se demostró que estas moléculas experimentaban cambios tanto cuantitativos como cualitativos a medida que los promastigotes se diferencian de promastigotes procíclicos no infectivos a metacíclicos o infectivos. Hoy en día, mediante técnicas de hibridización substractiva con cADN o de amplificación diferencial, se han logrado identificar genes cuyo patrón de expresión está íntimamente ligado al proceso de metaciclogénesis. Se han identificado moléculas como el producto del gen B y una proteína asociada con la metaciclogénesis (Mat-1), las cuales se expresan exclusivamente en promastigotes metacíclicos, mientras que otras como las proteínas Meta-1, SHERP y HASP se sobrexpresan en los promastigotes metacíclicos. Sin embargo, la función y asociación de estas proteínas con este patrón particular de expresión y virulencia se está empezando a evaluar.Palabras clave: metaciclogénesis, Leishmania, promastigotes, LPG, gp63. Metacyclogenesis: a basic process in Leishmania biologyMetacyclogenesis is a process whereby Leishmania transforms from poorly infective procyclic promastigotes into highly infective metacyclic promastigotes. In nature, metacyclogenesis occurs in the insect vector. This transformation is accompanied by an increased ability to infect and survive in the vertebrate host, where the parasite is attacked by the host's immune system. Metacyclogenesis has also been shown to occur in axenic cultures of promastigotes. Morphological changes in size and shape, and length of flagellum were first associated with differentiation in the insect gut and in different phases of growth in culture. Later, the expression of molecules such as LPG and the surface protease gp63 were associated with this process. These two molecules were observed to undergo qualitative and quantitative modifications as the promastigotes differentiated from procyclic to metacyclic forms. Using cDNA subtractive hybridization-based methods or differential amplification, previously unknown genes tightly linked to metacyclogenesis have been identified. Gene products exclusively expresed in metacyclic promastigotes included a gene B product and Mat-1 -a gene associated with metacyclogenesis. Other proteins, Meta-1, SHERP and HASP, were up-regulated during the met...

show abstract

Infectivity of the Subspecies of the Leishmania braziliensis Complex in Vivo and in Vitro

Cited by 42 publications

References 0 publications

Cultivation and characterization of stable Leishmania guyanensis complex axenic amastigotes derived from infected U937 cells.

Cultivation and characterization of stable Leishmania guyanensis complex axenic amastigotes derived from infected U937 cells.

Human monocytic U937 cells transfected with human hepatic inducible nitric oxide synthase exhibit leishmanicidal activity

Metaciclogénesis: un proceso fundamental en la biología de Leishmania

Contact Info

Product

Resources

About