Work

More time to kill: A longer liver stage increases T cell-mediated protection against pre-erythrocytic malaria

Year: 2023

Type: article

Abstract: Liver stage (LS) Plasmodia mature in 2-2.5 days in rodents compared to 5-6 days in humans. Plasmodium-specific CD8+ T cell expansion differs across these varied timespans. To mimic the kinetics of CD8+ T cells of human Plasmodium infection, a two-dose challenge mouse model that achieved 4-5 days of LS exposure was developed. In this model, mice were inoculated with a non-protective, low dose of late-arresting, genetically-attenuated sporozoites to initiate T cell activation and then re-inoculated 2-3 days later with wild-type sporozoites. Vaccines that partially protected against traditional challenge completely protected against two-dose challenge. During the challenge period, CD8+ T cell frequencies increased in the livers of two-dose challenged mice but not in traditionally challenged mice, further suggesting that this model better recapitulates kinetics of CD8+ T cell expansion in humans during the P. falciparum LS. Vaccine development and antigen discovery efforts may be aided by using this two-dose challenge strategy.

Source: iScience

DOI: 10.1016/j.isci.2023.108489