Indeed, a chimera in which the end of the A helix and the B helix of CD9 were substituted by the 21 corresponding residues of CD81 (CD9[81B]: VVDDDANNAKAVVKTFHETLD) could support infection by P. yoelii sporozoites to the same extent as CD81ccg9 (Fig. 4B). This evidence concerns the gene CD81 and infection.