Impact of Continuous Axenic Cultivation in Leishmania infantum Virulence

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Diana Moreira (Author) Other; Nuno Santarem (Author) Other; Ines Loureiro (Author) Other; Joana Tavares (Author) Other; Ana Marta Silva (Author) Other; Ana Marina Amorim (Author) Other; Ali Ouaissi (Author) Other; Anabela Cordeiro da Silva (Author) FFUP; Ricardo Silvestre (Author) Other

Journal

Title: PLoS Neglected Tropical Diseases

Vol. 6

Final page: e1469

ISSN: 1935-2727

Publisher: Public Library of Science

Indexing

ISI Web of Knowledge - 34 Citations

Scopus - 49 Citations

Scientific classification

FOS: Medical and Health sciences > Health sciences

Other information

Authenticus ID: P-002-GYP

DOI: 10.1371/journal.pntd.0001469

Abstract (EN): Experimental infections with visceral Leishmania spp. are frequently performed referring to stationary parasite cultures that are comprised of a mixture of metacyclic and non-metacyclic parasites often with little regard to time of culture and metacyclic purification. This may lead to misleading or irreproducible experimental data. It is known that the maintenance of Leishmania spp. in vitro results in a progressive loss of virulence that can be reverted by passage in a mammalian host. In the present study, we aimed to characterize the loss of virulence in culture comparing the in vitro and in vivo infection and immunological profile of L. infantum stationary promastigotes submitted to successive periods of in vitro cultivation. To evaluate the effect of axenic in vitro culture in parasite virulence, we submitted L. infantum promastigotes to 4, 21 or 31 successive in vitro passages. Our results demonstrated a rapid and significant loss of parasite virulence when parasites are sustained in axenic culture. Strikingly, the parasite capacity to modulate macrophage activation decreased significantly with the augmentation of the number of in vitro passages. We validated these in vitro observations using an experimental murine model of infection. A significant correlation was found between higher parasite burdens and lower number of in vitro passages in infected Balb/c mice. Furthermore, we have demonstrated that the virulence deficit caused by successive in vitro passages results from an inadequate capacity to differentiate into amastigote forms. In conclusion, our data demonstrated that the use of parasites with distinct periods of axenic in vitro culture induce distinct infection rates and immunological responses and correlated this phenotype with a rapid loss of promastigote differentiation capacity. These results highlight the need for a standard operating protocol (SOP) when studying Leishmania species.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12