HIV Type 1 V3 Peptide Constructs Act Differently on HIV Type 1 Infection of Peripheral Blood Lymphocytes and Macrophages

Abstract

We have previously shown that a multibranched peptide construct derived from the tip of the B clade V3 loop consensus sequence (MPBC1: [GPGRAF]8-[K]4-[K]2-K-βA-OH), but not V3 monomer peptides, inhibit human immunodeficiency virus type 1 (HIV-1) infection and syncytium formation of CD4⁺ T cells from immortalized lines. Here, we show that MBPC1 attaches to normal peripheral blood lymphocytes (PBLS) and monocytes but not to erythrocytes. While treatment with 5 μM MBPC1 had no significant antiviral effect on HIV-1_Ba-L infection of monocyte-derived macrophages as assessed by p24 production in culture supernatants, this dose inhibited both HIV-1_Ba-L and HIV-_LAI infection of PBLs. Virus production was inhibited up to 90% when MBPC1 was added to PBLs immediately after the virus, and was inhibited about 50% when it was added after 3 days; no effect was noted when it was added 7 days postinfection. MBPC1 did not affect PBL growth or IL-2 receptor and CD4 surface expression level. These observations suggest a selective antiviral effect of MBPC1 on CD4⁺ T lymphocytes and they provide additional circumstantial evidence that HIV-1 enters lymphocytes and monocytes by different mechanisms.