Effect of the haematocrit layer geometry on Plasmodium falciparum static thin-layer in vitro cultures

<p>Abstract</p> <p>Background</p> <p><it>In vitro </it>cultivation of <it>Plasmodium falciparum </it>is usually carried out through the continuous preservation of infected erythrocytes deposited in static thin layers of settled haematocrit. This technique, called the candle-jar method, was first achieved by Trager and Jensen in 1976 and has undergone slight modifications since then. However, no systematic studies concerning the geometry of the haematocrit layer have been carried out. In this work, a thorough investigation of the effects of the geometric culturing conditions on the parasite's development is presented.</p> <p>Methods</p> <p>Several experimental trials exploring different settings have been carried out, covering haematocrit layer depths that ranged from 6 mm to 3 mm and separation between the walls of the culturing device that ranged from 7.5 mm to 9 mm. The obtained results have been analysed and compared to different system-level models and to an Individual-Based Model.</p> <p>Conclusion</p> <p>In line with the results, a mechanism governing the propagation of the infection which limits it to the vicinity of the interface between the haematocrit layer and the culture medium is deduced, and the most appropriate configurations are proposed for further experimental assays.</p

Lymphocyte responsiveness to a candidate malaria sporozoite vaccine (R32tet32) of individuals with naturally acquired Plasmodium falciparum malaria.

Lymphocyte proliferative responses to the candidate malaria sporozoite vaccine antigen R32tet32 were evaluated in 29 patients with acute Plasmodium falciparum malaria, 20 convalescent patients, 11 nonimmune individuals, and 22 healthy residents of two endemic malarious areas in Thailand. The results indicate that 14 of 20 (70%) convalescent patients and 14 of 22 (64%) residents of endemic areas responded to the R32tet32 antigen. However, only 8 of 29 (28%) patients with acute P. falciparum malaria responded. When 4 of the convalescent patients who remained in a malaria-free area were restudied 5-10 months after the acute infection, they were either not responsive or their responses had greatly diminished. These findings show that sensitization to R32tet32 occurs following a natural P. falciparum infection, but the cellular immune response to sporozoite antigens may be short-lived and may be suppressed during acute P. falciparum malaria