Infectious plasmodium sporozoites grown in vitro

Inventors

EAPPEN, Abraham G. • Hoffman, Stephen L.

Assignees

Sanaria Inc

Abstract

The application is directed to in vitro-reared Plasmodium sporozoites of human host range wherein sporogony from gametocyte stage to sporozoite stage is external to mosquitoes, and methods of producing the same. Provided herein are in vitro-reared infectious Plasmodium sporozoites (SPZ) of human host range, particularly P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi, wherein sporogony from gametocyte stage to sporozoite stage is external to mosquitoes, and methods of producing the same.

Core Innovation

The invention is directed to a composition comprising in vitro-reared Plasmodium-species ookinetes of human host range, where development of the ookinetes from the gametocyte stage occurs in a culture external to mosquitoes. The composition is defined as being absent any mosquito material.

The described concept broadens Plasmodium species coverage for human host range, including Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium knowlesi, by enabling development external to mosquitoes. The culture environment replaces mosquito-dependent sporogony by providing a development pathway in vitro from gametocytes to ookinetes.

The disclosures further align the in vitro-reared stage with downstream infectious sporozoites, including mature infectious P. falciparum sporozoites. The document reports substantially higher in vitro oocyst numbers relative to mosquitoes and includes an infectivity comparison using a hepatocyte potency assay, with reference to sporozoites being fresh, aseptic purified, and in a cryopreserved reference context.

The described workflow includes stages from exflagellation to lectin agglutination, collection for inoculation into ookinete medium, subsequent oocyst medium, and harvest of sporozoites. The document also describes optional embodiments regarding the absence of attendant mosquito material, and includes a 3D matrix approach using transwell inserts.

Claims Coverage

The independent claim (clm-00001) covers an in vitro-reared, human-host-range Plasmodium ookinete composition formed from gametocytes in a culture external to mosquitoes, explicitly requiring absence of mosquito material. Dependent claims further refine the composition by specifying aseptic preparation, cryopreservation, and narrowing to Plasmodium falciparum.

Overall, the claim set centers on an in vitro production of Plasmodium-species human-host-range ookinetes from gametocytes in a culture external to mosquitoes, while requiring that the composition contains no mosquito material, with dependent variations adding aseptic preparation, cryopreservation, and restriction to Plasmodium falciparum.

Stated Advantages

Documented Applications