HIV TYPE-1 V3 PEPTIDE CONSTRUCTS ACT DIFFERENTLY ON HIV TYPE-1 INFECTION OF PERIPHERAL-BLOOD LYMPHOCYTES AND MACROPHAGES

We have previously shown that a multibranched peptide construct derive d from the tip of the B clade V3 loop consensus sequence (MPBC1: [GPGR AF]8-[K]4-[K]2-K-beta A-OH), but not V3 monomer peptides, inhibit huma n immunodeficiency virus type 1 (HIV-1) infection and syncytium format ion of CD4(+) T cells from immortalized lines. Here, we show that MBPC 1 attaches to normal peripheral blood lymphocytes (PBLS) and monocytes but not to erythrocytes. While treatment with 5 mu M MBPC1 had no sig nificant antiviral effect on HIV-1(Ba-L) infection of monocyte-derived macrophages as assessed by p24 production in culture supernatants, th is dose inhibited both HIV-1(Ba-L) and HIV-1(LAI) infection of PBLs. V irus production was inhibited up to 90% when MBPC1 was added to PBLs i mmediately after the virus, and was inhibited about 50% when it was ad ded after 3 days; no effect was noted when it was added 7 days postinf ection, MBPC1 did not affect PBL growth or IL-2 receptor and CD4 surfa ce expression level, These observations suggest a selective antiviral effect of MBPC1 on CD4(+) T lymphocytes and they provide additional ci rcumstantial evidence that HIV-1 enters lymphocytes and monocytes by d ifferent mechanisms.