Infection with lesion-derived Leishmania mexicana amastigotes inhibited LPS-induced IL-12 production by mouse bone marrow-derived macrophages. This effect was associated with expression of cysteine peptidase B (CPB) because amastigotes of CPB deletion mutants had limited ability to inhibit IL-12 production, whereas preincubation of cells with a CPB inhibitor, cathepsin inhibitor IV, was able to...

balb/c mice are highly susceptible to infection with the protozoan parasite leishmania major. this susceptibility has been attributed in part to the expansion of th2 cells and production of their cytokines, il-4 and il-10 and down-regulation of th1 cytokine, inf-γ. the inability of susceptible hosts to mount the immune response necessary to activate macrophage and destroy the parasites can be d...

Signaling through exposed phosphatidylserine (PS) is fundamental for the TGFbeta1-dependent, noninflammatory phagocytosis of apoptotic cells. This same mechanism operates in the internalization of amastigotes of Leishmania (L) amazonensis (L(L)a) in a process quoted as apoptotic mimicry. Now we show that the host modulates PS exposure by the amastigotes and, as a consequence, BALB/c mice-derive...

Four diamines and three amino alcohols derived from 1-decanol, 1-dodecanol and 1,2-dodecanediol were evaluated in an in vitro assay against a mixture of trypomastigote and intracellular amastigote forms of Trypanosoma cruzi. Two of these compounds (6 and 7) showed better activity against both proliferative stages of T. cruzi than the positive control benznidazole, three were of similar potency ...

Leishmaniasis is among the world's most neglected diseases. Currently available drugs for treatment present drawbacks, urging the need for more effective, safer, and cheaper drugs. A small library of artemisinin-derived trioxanes and synthetic trioxolanes was tested against promastigote and intramacrophage amastigote forms of Leishmania infantum. The trioxolanes LC50 and LC95 presented the best...

Antitrypanosomal activity of chloroform extract of Senna villosa leaves was evaluated in the sub acute phase of mice infected with Trypanosoma cruzi. Oral doses of 3.3, 6.6 and 13.2 µg/g were tested during 15 days on infected mice BALB/c, beginning treatment 40 days after infection to evaluate specifically the antitrypanosomal activity over the amastigote form of the parasite. Two different amo...

In spite of the growing knowledge obtained about immune control of Trypanosoma cruzi infection, the mechanisms responsible for the variable clinico-pathological expression of Chagas disease remain unknown. In a twist from previous concepts, recent studies indicated that tissue parasitism is a pre-requisite for the development of chronic myocarditis. This fundamental concept, together with the r...

this study was carried out to identify the efficacy of caparis spinosa root extract on promastigotes and amastigotes of leishmania major . caparis spinosa extracts were prepared. promastogotes of  l.major (1×10 6 parasites/ml)were incubated at 26 ºc for 24,48 and 72hours in fresh medium(nnn), in absence or presence of different concentrations (0.1,0.3,0.5,0.7,0.9 mg/ml) of caparis spinosa metha...

A massive and homogeneous amount of amastigote-like forms was detected in the stomodeal valve (SV) and the thoracic mid-gut (TMG) of Leishmania major-infected Phlebotomus papatasi, which received a second blood meal 13 to 21 days post-infection on healthy anaesthetized hamsters. After re-feeding, the infected sand flies were dissected out to examine the morphology of the parasite in SV, TMG and...