Table 1.

Neutralization analysis of heavy-chain-only antibodies (HCAbs) against X-31 influenza virus.

	NI	I	NI	I	NI	I	NI	I	NI	NI	NI
HCAbs	2F4	2F4	1F3	1F3	3A8	3A8	4H1	4H1	7F2	HC19	X31
Concentration (mg/ml)	0.85	0.9	1.2	1.2	0.48	0.55	1.6	0.8	0.4	NK	NK
X31(50% reduction)	32	640	>256	>1,280	16	20	2	2	2	6,400	2,560
X31 (any visible reduction)	64	>1,280	>256	>1,280	64	160	2	8	64	>12,800	>5,120

The numbers show best neutralizing capacity for 1F3 HCAb at ≥0.9 μg/ml (~11nM), followed by 2F4 at 1.4 µg/ml (~18nM).

NI, not preincubated with the virus; I, preincubated with the virus; NK, not known; neutralization titer, reciprocal of the 50% plaque reduction.