Papel del mecanismo de inmunoadherencia de "Leishmania" en la infección humana

Abstract

La leishmaniosis es una enfermedad parasitaria causada por protozoos hemoflagelados del genero Leishmania que se transmite al hombre y a otros vertebrados a través de la picadura de un díptero de la familia Plebotominae. Cuando un flebótomo infectado pica al hospedador vertebrado, perfora la piel con su probóscide buscando las vénulas de la dermis, las lacera y provoca un pequeño hematoma donde deposita los promastigotes. Tras el contacto con la sangre tiene lugar la activación del complemento y deposición del C3 en la superficie del parásito. En primates, los promastigotes opsonizados se unen a eritrocitos y posteriormente son transferidos a las células aceptoras de la sangre: los leucocitos...The leishmaniosis are vector-borne diseases caused by trypanosomatid protozoa of the genus Leishmania. These parasites have a heteroxenous life cycle, living as extracellular flagellated promastigotes in the digestive tract of the insect vector and as obligate intracellular sessile amastigotes within mononuclear phagocytes in vertebrate hosts. Leishmania is transmitted to susceptible vertebrate hosts through the bite of infected sandflies of the genus Phlebotomus. Phlebotomine sandflies are telmophage diptera that feed from hematomas; infected females inoculate promastigotes into hematomas in host skin while probing for dermal capillaries. After blood contact, promastigotes are opsonized by host serum factors that trigger complement activation and C3 deposition on parasites. In primate blood, C3-opsonized promastigotes immune-adhere to erythrocytes and in non-primate mammalian blood, to platelets. Erythrocyte-bound promastigotes are subsequently shuttled to acceptor blood leukocytes and the C3-coated parasites are endocytosed by polymorphonuclear (PMN) phagocytes and monocytes. Inside phagolysosomes of permissive leukocytes, promastigotes differentiate to amastigotes and establish infection...