As NRAMP2, MXRA8, LDLRAD3, VLDLR, and ApoER2 are not used by all alphaviruses, and blockade or loss of expression of some of these proteins does not abrogate virus infection, we postulated the existence of additional entry factors that could mediate infection, possibly in a cell-type specific manner15. This evidence concerns the gene MXRA8 and infection.