Human parainfluenza virus type 1 (hPIV1) and type 3 (hPIV3) initiate
infection by
sialic acid binding. Here, we investigated
sialic acid linkage specificities for binding and
infection of hPIV1 and hPIV3 by using
sialic acid linkage-modified cells treated with sialidases or
sialyltransferases. The hPIV1 is bound to only α2,3-linked
sialic acid residues, whereas hPIV3 is bound to α2,6-linked
sialic acid residues in addition to α2,3-linked
sialic acid residues in human red blood cells. α2,3 linkage-specific
sialidase treatment of LLC-MK2 cells and A549 cells decreased the infectivity of hPIV1 but not that of hPIV3. Treatment of A549 cells with α2,3 linkage-specific
sialyltransferase increased infectivities of both hPIV1 and hPIV3, whereas α2,6 linkage-specific
sialyltransferase treatment increased only hPIV3 infectivity. Clinical isolates also showed similar
sialic acid linkage specificities. We concluded that hPIV1 utilizes only α2,3
sialic acid linkages and that hPIV3 makes use of α2,6
sialic acid linkages in addition to α2,3
sialic acid linkages as viral receptors.