Nonobese Diabetic (NOD) Mice Lack a Protective B-Cell Response against the "Nonlethal" 17XNL Malaria Protozoan.

. 17XNL is a nonlethal malaria strain in mice of different genetic backgrounds including the C57BL/6 mice (I-A/I-E) used in this study as a control strain. We have compared the trends of blood stage infection with the nonlethal murine strain of 17XNL malaria protozoan in immunocompetent Nonobese Diabetic (NOD) mice prone to type 1 diabetes (T1D) and C57BL/6 mice (control mice) that are not prone to T1D and -cure the 17XNL infection. Prediabetic NOD mice could not mount a protective antibody response to the 17XNL-infected red blood cells (iRBCs), and they all succumbed shortly after infection. Our data suggest that the lack of anti- 17XNL-iRBCs protective antibodies in NOD mice is a result of parasite-induced, Foxp3 T regulatory (Treg) cells able to suppress the parasite-specific antibody secretion. . The NOD mouse model may help in identifying new mechanisms of B-cell evasion by malaria parasites. It may also serve as a more accurate tool for testing antimalaria therapeutics due to the lack of interference with a preexistent -curing mechanism present in other mouse strains.