TABLE 3.

Effects of different sialyltransferases on rhesus erythrocytes pretreated with neuraminidase^a

Sialyltransferase specificity	Concn (mU/ml)	Fold change in HA titer
		AAV4	AAV5
No treatment		<2	<2
α2,3 (O)	2	4	<2
	20	64	<2
α2,3 (N)	20	<2	<2
	50	<2	16

^aRhesus cells were treated with 2 mU of neuraminidase/ml from A. ureafaciens to remove sialic acid and then incubated with different concentrations of specific sialyltransferases for 3 h. The red cells were washed and tested for an increase in the HA titer. A change of greater than fourfold was considered significant. Values presented are fold changes in HA titer compared to red cells treated with only neuraminidase.