Development and Assessment of Transgenic Rodent Parasites for the Preclinical Evaluation of Malaria Vaccines

Abstract

Rodent transgenic parasites are useful tools for the preclinical evaluation of malaria vaccines. Over the last decade, several studies have reported the development of transgenic rodent parasites expressing P. falciparum antigens for the assessment of vaccine-induced immune responses, which traditionally have been limited to in vitro assays. However, the genetic manipulation of rodent Plasmodium species can have detrimental effects on the parasite's infectivity and development. In this chapter, we present a few guidelines for designing transfection plasmids, which should improve transfection efficiency and facilitate the generation of functional transgenic parasite strains. In addition, we provide a transfection protocol for the development of transgenic P. berghei parasites as well as practical methods to assess the viability and infectivity of these newly generated strains throughout different stages of their life cycle. These techniques should allow researchers to develop novel rodent malaria parasites expressing antigens from human malaria species and to determine whether these transgenic strains are fully infectious and thus represent stringent platforms for the in vivo evaluation of malaria vaccine candidates.

Leveraging genome editing to functionally evaluate Plasmodium diversity

“…Pioneering studies reported the use of rodent malaria parasites to investigate the functional relevance of P. falciparum liver stage [79] and blood stage [58] vaccine candidates. Most of the recently developed P. berghei chimeras have been accomplished using the twostep gene insertion marker out technique [80], which has been used in assessing both transmission-blocking [81] and pre-erythrocytic vaccines [82,83], enabling successful replacement of orthologous gene targets and also marker-free parasite lines. More recently, Shinzawa and colleagues developed a transgenic P. berghei line constitutively expressing the Sp-Cas9 gene [84], which could be of great interest for future work involving P. berghei as a model.…”

Human challenge trials in vaccine development, Rockville, MD, USA, September 28–30, 2017

“…These models allow the use of mice for testing novel CSP-based vaccine candidates, such as a self-assembling protein nanoparticlebased malaria vaccine [9], or monoclonal antibodies binding to the vaccine antigen [10], potentially defining new protective epitopes. Specific chimeras can be engineered to study other antigens, such as TRAP or CelTOS, and guidelines have been published [11].…”

Human sterile immunity to Plasmodium vivax malaria correlates with specific antibody response elicited by immunization with radiation-attenuated sporozoites

“…This prevents malaria disease caused by asexual parasite blood stages and further transmission mediated by sexual blood stages. Moreover, genetically (GAP) and chemically attenuated (CAP) P. falciparum and rodent malaria parasites have con rmed the protective e cacy of whole attenuated parasites [16][17][18][19][20][21][22][23][24] .…”