TABLE 1.

Reactivity of a panel of rhesus monkey sera with WNV, SLEV, and/or recombinant WNV E protein domain-III antigens in an indirect IgG ELISA, HI test, and PRNT₉₀ test

Serum	Absorbance in IgG indirect ELISAa					Titer in HI		WNV PRNT90
	WNV Ag	SLEV Ag	r-EIII	BSA	r-EIII titerb	WNV	SLEV	No pretreatment	+ β-MEd
CL35	0.452	0.574	1.374	0.121	6,400	320	80	≥320	≥320
CL07	0.620	0.588	1.346	0.156	3,200	320	160	≥320	160
CK62	0.452	0.424	1.251	0.073	NTc	320	160	80	NT
CP50	0.341	0.431	0.974	0.049	1,600	80	20	40	40
CL93	0.341	0.643	0.763	0.094	1,600	640	160	80	NT
CL80	0.495	0.591	0.745	0.061	1,600	640	160	≥320	160
CJ13	0.424	0.512	0.650	0.073	400	40	<20	40	NT
CP51	0.271	0.439	0.326	0.069	400	320	80	40	NT
CV38	0.136	0.322	0.103	0.127	<100	640	160	80	<20
CL13	0.119	0.266	0.174	0.051	<100	640	160	40	<20
CM08	0.165	0.222	0.046	0.060	<100	<20	<20	<20	NT
CP48	0.109	0.184	0.048	0.043	<100	<20	<20	<20	NT
CM13	0.117	0.251	0.095	0.075	<100	<20	<20	<20	NT
CI94	0.122	0.129	0.039	0.062	<100	<20	<20	<20	NT
CL14	0.219	0.329	0.049	0.060	<100	<20	<20	<20	NT
CM07	0.143	0.241	0.070	0.094	<100	<20	<20	<20	NT
CL87	0.132	0.176	0.052	0.065	<100	<20	<20	<20	NT
CK74	0.189	0.409	0.054	0.053	<100	<20	<20	<20	NT
CI72	0.196	0.281	0.065	0.059	<100	<20	<20	<20	NT

^aAbsorbance values given are means of triplicate wells. Sera were screened against WNV and SLEV antigens and the r-EIII protein at a 1:100 dilution. BSA-coated wells were used as a control for nonspecific binding of antibodies.

^bTo determine WNV r-EIII IgG ELISA endpoint titers, a positive result was defined as being those wells that had a corrected absorbance (i.e., absorbance versus r-EIII minus absorbance versus the BSA control well) ≥0.2.

^cNT, not tested.

^dPRNT₉₀ titer following pretreatment of serum samples with 0.1M β-mercaptoethanol to reduce IgM antibodies.