A. (I) Schematic of PfCSP (NF54), with region 1 (R1) in red, NANP repeats in orange, NPDP/NVDP repeats in blue and region 2 (R2) thrombospondin repeats (TSR) in green. Junctional epitope NPDP19 included in our (II) KLH-based prototype malaria vaccine candidate and malaria peptide21 published (Kisalu et al., 2018) are indicated. Numbering (95–115) corresponds to PfCSP numbering. Schematic adapted from (Cockburn and Seder, 2018a; Kisalu et al., 2018).
B. ELISA to assess if NPDP19-peptide can be recognized by both iGL-CIS43 (purple) and mature CIS43 (black) antibodies in the context of KLH. The red line indicates HIV-1 bNAb VRC01, used as a negative control.
C. HiGL-CIS43κiGL-CIS43 B cell transfer system used for (D).
D. Representative flow cytometry graphs for recipient mice adoptively transferred to achieve precursor frequencies of 1:104, 1:105 and 1:106, immunized with PfCSP [50 µg/mouse]/Alhydrogel (n=5 per cell dilution) or NPDP19-KLH [50 µg/mouse]/Alhydrogel (n=5 per cell dilution). (Left to right) Graphs indicate total GC-responses, HiGL-CIS43κiGL-CIS43 CD45.2 B cell responses, and PfCSP-binding of CD45.2 B cells. Percentages based on parent populations.
E. Quantification of (D). Data normalized to B220+ B cells.
P values calculated by 2-way ANOVA for multiple comparisons (panel E). *P < 0.05; **P<0.01***; P<0.001; ****P<0.0001; ns, statistically non-significant differences.
See also Figure S2.