Mutant/mutation
In the mutant (CS^5MΔN) the wild type cs gene is replaced with a mutated cs gene carrying 5 mutations that changed the natural H-2K^d restricted epitope SYIPSAEKI to SIINFEKL, an H-2K^b restricted epitope and the mutated cs gene lacks the entire N terminus excluding the signal sequence (including region I).

Protein (function)
The CS protein is the major protein on the surface of sporozoites and is critical for development of sporozoites within the oocysts and is involved in motility and invasion of both the salivary gland of the mosquito and the liver cells. The protein is also found on the oocyst plasma membrane and on the inner surface of the oocyst capsule. Specific motifs in CS are involved in sporozoite binding to mosquito salivary glands and in sporozoite attachment to heparan sulfate proteoglycans in the liver of the mammalian host. During substrate-dependent locomotion of sporozoites, CS is secreted at the sporozoite anterior pole, translocated along the sporozoite axis and released on the substrate at the sporozoite posterior pole. Following sporozoite invasion of hepatocytes, the CS is released in the host cell cytoplasm.

Phenotype
See additional information below

Additional information
From the paper:
'As a second approach, we generated mutant parasites that expressed the SIINFEKL epitope in a CS-restricted manner and were unable to migrate out of the skin due to a deletion in the N-terminal third of the CS protein (RMgm-609], P. berghei CS^5MΔN. In further agreement with the hypothesis that sporozoite motility is required for parasite entry into the lymphatics, P. berghei CS^5MΔN sporozoites exhibited a severe impairment in their migration to the DLN. To evaluate the effect of these changes in DLN access on the development of cell-mediated immunity, mice were given CFSE-labeled OT-1 cells, injected ID with P. berghei CS^5M (RMgm-609] or P. berghei CS^5MΔN sporozoites, and OT-1 proliferation was examined 3 days later in the DLN. OT-1 proliferation was significantly reduced in mice injected with P. berghei CS^5MΔN sporozoites. To determine whether the diminished CD8+ T cell response observed at day 3 was due to a delay in sporozoite migration to the DLN, rather than an absolute reduction, we measured the expansion of OT-1 cells in the DLN, spleen, and liver 10 days after ID inoculation of P. berghei CS^5M or P. berghei CS^5MΔN sporozoites. In line with our previous findings, we found that ID immunization with P. berghei CS^5MΔN sporozoites led to drastically reduced OT-1 responses 10 days after immunization as compared to P. berghei CS^5M sporozoites. Importantly, when injected IV, P. berghei CS^5MΔN sporozoites were fully infectious and induced similar OT-1 responses in the spleen and liver as compared to control parasites (P. berghei CS^5M). These findings demonstrate that the SIINFEKL epitope is expressed by the mutant parasite and is efficiently presented by APCs upon sporozoite access to lymphoid organs. Together, our studies with Fab-treated and transgenic parasites establish a critical role for sporozoite migration to the DLN in CD8+ T cell priming after ID inoculation.

Other mutants
RMgm-613: A mutant with the wild type cs gene replaced with a mutated cs gene carrying 5 mutations that changed the natural H-2K^d restricted epitope SYIPSAEKI to SIINFEKL, an H-2K^b restricted epitope

RMgm-609: A mutant with the wild type csp replaced with a mutated csp containing a specific deletion of entire N terminus, (including region I) and  excluding the signal sequence (amino acids NKSIQAQRNLNELCYNEGNDNKLYHVLNSKNGKIYNRNTVNRLLADAPEGKKNEKKNEKIERNNKLKQP)