Full maturation of in vitro Plasmodium falciparum oocysts using the AlgiMatrix 3D culture system.

Background: Plasmodium falciparum oocysts undergo growth and maturation in a unique setting within the mosquito midgut, firmly situated between the epithelium and the basal lamina. This location exposes them to specific nutrient exchange and metabolic processes while in direct contact with the mosquito haemolymph. The limited availability of in vitro culture systems for growth of the various P. falciparum mosquito stages hampers study of their biology and impedes progress in combatting malaria.

Methods: An artificial in vitro environment was established to mimic this distinctive setting, transitioning from a 2D culture system to a 3D model capable of generating fully mature oocysts that give rise to in vitro sporozoites.

Results: A two-dimensional (2D) chamber slide was employed along with an extracellular matrix composed of type IV collagen, entactin, and gamma laminin. This matrix facilitated development of the optimal medium composition for cultivating mature P. falciparum oocysts in vitro. However, the limitations of this 2D culture system in replicating the in vivo oocyst environment prompted a refinement of the approach by optimizing a three-dimensional (3D) alginate matrix culture system. This new system offered improved attachment, structural support, and nutrient exchange for the developing oocysts, leading to their maturation and the generation of sporozoites.

Conclusions: This technique enables the in vitro growth of P. falciparum oocysts and sporozoites.