Fig. 2

Heterologous cross-species immunization increases secondary liver burden compared to homologous immunization in part by circumventing homologously directed antibody responses. a Liver burden at 44 h after single (Py), homologous (Py → Py) or heterologous (Pb → Py) RAS immunizations of BALB/cj mice compared to uninfected animals (none). b Liver burden at 24 h after final immunization of WT C57BL/6 or μMT mice with either single (Pb) or double (Pb → Pb) homologous RAS regimens. c Liver burden at 24 h after homologous RAS immunization of BALB/cj mice mock-treated or treated with anti-CD20 antibodies to deplete B cells. *p < 0.05,**p < 0.01, ***p < 0.001,****p < 0.0001, Students t-test. All doses were 1 × 10⁴ RAS. Plasmodium 18S rRNA content was normalized to the host GAPDH mRNA and differences are expressed in log₁₀ changes in parasite 18S rRNA concentration relative to the single exposure control average