Fig. 1: Serotype distribution and immunogenicity of PrsA1 and PrsA2.

a Western blot detection of PrsA1 and PrsA2 in crude membrane extracts collected from eight representative clinical GAS isolates of different emm-types. (M1 strain A20, M4 strain 6043-05, M49 strain NTU43, M6 strain NTU45, M58 strain NTU46, M12 strain NTU25, M89 strain NTU30, M124 strain NTU32). b, c Expression of prsA1 and prsA2 in response to human serum. M1 GAS (strain A20) were treated with RPMI 1640 medium (Mock) or RPMI 1640 medium with 10% normal human serum (NHS) for 30 min, followed by analyzing the transcript levels of prsA1 (b) and prsA2 (c) by RT-qPCR analysis. Data shown were normalized with recA, gyrsA and proS and presented as means ± SD from five independent experiments. Statistical analysis was performed using Student’s t test. ** <0.01; *** <0.005. d His-tagged PrsA1 and PrsA2 proteins (0.5 µg) were separated by 10% SDS-PAGE and probed with murine sera collected from GAS-infected mice (1:500 dilution). e His-tagged PrsA1, PrsA2 and NlpI proteins (0.5 µg) were separated by 10% SDS-PAGE and probed with human sera obtained from patients with invasive GAS infections and healthy adults (1:300 dilution). f–h Serum IgG cross-reactivity to human heart tissue proteins. Western blot analysis of human heart lysates with antisera from rabbits immunized with PrsA1 (f) and PrsA2 (g) or mice immunized with M1 proteins (h). Purified recombinant PrsA1, PrsA2 and M1 proteins were included as positive controls.