Table 2. Anti-HIV Activity of FC131 and the Derivatives 15a−g.

	EC50 (nM)a
peptide	NL4-3	IIIB	Ba-L
FC131 (2)	21 ± 4.3	21 ± 5.9	−b
FC122 (3)	7.6 ± 0.34	7.6 ± 1.1	−b
15a	1.3 ± 0.43	0.61 ± 0.10	−b
15b	1.4 ± 0.44	1.0 ± 0.23	−b
15c	2.2 ± 0.04	2.0 ± 0.59	−b
15d	4.4 ± 1.0	6.3 ± 0.47	−b
15e	1.9 ± 0.47	1.2 ± 0.29	−b
15f	300 ± 57	258 ± 47	−b
15g	248 ± 55	238 ± 37	−b

^aEC₅₀ is the concentration that blocks HIV-1 infection by 50%.

^bNo inhibitory activity was observed at 10 μM.