TABLE 1.

Neutralizing antibody titers in response to scSIV immunization

Wk (sample)	50% Neutralization titer for strain and macaque no.a:
	Mm 12-94b			Mm 169-84b			Mm 245-91b			Mm 415-90b
	239	316	251LA	239	316	251LA	239	316	251LA	239	316	251LA
0 (1st dose)	—	NT	—	—	NT	—	—	NT	—	—	NT	—
8 (2nd dose)	—	NT	—	—	NT	—	—	NT	—	—	NT	—
11	—	NT	—	—	NT	160	—	NT	20	—	NT	20
33 (3rd dose)	—	NT	—	—	NT	—	—	NT	—	—	NT	—
35	—	60	240	—	40	320	—	80	160	—	60	320
39 (challenge)	—	30	80	—	80	120	—	40	60	—	60	80

^aNeutralizing antibody titers indicate the reciprocal of the plasma dilution that reduced SIV infection of CEMx174SIV-SEAP cells containing a Tat-inducible SEAP reporter construct by 50%. Antibody neutralization was tested against SIV_mac239 (239), SIV_mac316 (316), and a lab-adapted strain of SIV_mac251 (251_LA). Samples that were negative for virus neutralization at the lowest dilution tested (<1:20) are indicate by a dash (—). Time points that were not tested for neutralization of SIV_mac316 are indicated by NT. Two different pools of positive-control plasma from SIV-infected rhesus macaques gave titers of 3,840 and 10,240 against lab-adapted SIV_mac251, 2,560 against SIV_mac316, and 20 and 70 against SIV_mac239. Negative-control pools from uninfected animals were unable to neutralize either SIV_mac251 or SIV_mac239.

^bMm 12-94, Mm 169-84, Mm 245-91, and Mm 415-90 were immunized with scSIV_mac239Nef^sff and scSIV_mac316Nef^sff at weeks 0, 8, and 33.