In vivo inhibition of HIV-1 by ISIS 5320. SCID-hu Thy/Liv mice infected with HIV-1 isolate NL4-3, JD, or EW were administered various doses of ISIS 5320 and the control oligonucleotide ISIS 9477. Implant p24 levels (in picograms per 106 cells) were converted to a percentage of the level for the control by dividing the values for treated mice by the mean value for untreated mice, and the results are expressed as the mean ± standard error. Data for treated mice (four to seven mice per dosage group) were compared to those for untreated infected mice, and P values of ≤0.05 were considered statistically significant (indicated by an asterisk). Mean p24 values (in picograms per 106 cells) for untreated groups were as follows: 290 (experiment 1), 500 (experiment 2), and 170 (experiment 3) for NL4-3-infected implants, 93 for EW-infected implants, and 800 for JD-infected implants.