TY - JOUR
T1 - Entamoeba histolytica
T2 - Mechanism of decrease of virulence of axenic cultures maintained for prolonged periods
AU - Olivos, Alfonso
AU - Ramos, Espiridión
AU - Nequiz, Mario
AU - Barba, Carlos
AU - Tello, Eusebio
AU - Castañón, Guadalupe
AU - González, Augusto
AU - Martínez, Rubén D.
AU - Montfort, Irmgard
AU - Pérez-Tamayo, Ruy
N1 - Funding Information:
This work was supported in part by CONACyT Grants 30831-M, DGAPA Grant IN-244202 and 241402. We received excellent technical help from Pedro Balderas, Víctor Cornejo and Marco E. Gudiño as well as the professional animal care of Ricardo Vargas and Daniel Sánchez Almaraz.
PY - 2005/7
Y1 - 2005/7
N2 - Intraportal injection of non-virulent E. histolytica (derived from prolonged axenic culture of virulent E. histolytica) strain HM1-IMSS in normal hamsters results in no liver lesions and disappearance of the parasites 48-72 h after injection. Viability of non-virulent E. histolytica after 2 h of in vitro incubation in either fresh or decomplemented hamster serum is the same as control virulent E. histolytica (50-90%). In hamsters made leukopenic, or both leukopenic + hypocomplementemic, or hypocomplementemic + sephadex microspheres (to produce focal liver ischemia) intraportally injected non-virulent E. histolytica cause no lesions and disappear after 24 h. In addition, neither hypocomplementemia nor immunosuppression with cyclosporin A prolonged the survival of non-virulent E. histolytica. Methyl prednisolone treatment of hamsters resulted in survival of large numbers of non-virulent E. histolytica in the liver, with little inflammation and minimal tissue damage, for up to 7 days. Inflammatory cells (macrophages) would appear to be chiefly responsible for elimination of non-virulent E. histolytica. Parallel experiments with E. dispar suggest a different mechanism for its non-pathogenicity.
AB - Intraportal injection of non-virulent E. histolytica (derived from prolonged axenic culture of virulent E. histolytica) strain HM1-IMSS in normal hamsters results in no liver lesions and disappearance of the parasites 48-72 h after injection. Viability of non-virulent E. histolytica after 2 h of in vitro incubation in either fresh or decomplemented hamster serum is the same as control virulent E. histolytica (50-90%). In hamsters made leukopenic, or both leukopenic + hypocomplementemic, or hypocomplementemic + sephadex microspheres (to produce focal liver ischemia) intraportally injected non-virulent E. histolytica cause no lesions and disappear after 24 h. In addition, neither hypocomplementemia nor immunosuppression with cyclosporin A prolonged the survival of non-virulent E. histolytica. Methyl prednisolone treatment of hamsters resulted in survival of large numbers of non-virulent E. histolytica in the liver, with little inflammation and minimal tissue damage, for up to 7 days. Inflammatory cells (macrophages) would appear to be chiefly responsible for elimination of non-virulent E. histolytica. Parallel experiments with E. dispar suggest a different mechanism for its non-pathogenicity.
UR - http://www.scopus.com/inward/record.url?scp=20444502898&partnerID=8YFLogxK
U2 - 10.1016/j.exppara.2005.03.020
DO - 10.1016/j.exppara.2005.03.020
M3 - Artículo
C2 - 15955329
AN - SCOPUS:20444502898
SN - 0014-4894
VL - 110
SP - 309
EP - 312
JO - Experimental Parasitology
JF - Experimental Parasitology
IS - 3 SPEC. ISS.
ER -
