Synthesis of Potential Anti-AIDS Amphiphiles. A New Efficient Acylation of Amino-Naphthalene Disulfonic Acid Derivatives

Synthetic soluble analogs of galactosylceramide (GalCer) bind to the V3 domain of HIV-1 gp120 and inhibit HIV-1-induced fusion and entry

Galactosylceramide (GalCer) is an alternative receptor allowing human immunodeficiency virus (HIV)-1 entry into CD4-negative cells of neural and colonic origin. Several lines of evidence suggest that this glycosphingolipid recognizes the V3 region of HIV-1 surface envelope glycoprotein gp120. Since the V3 loop plays a key role in the fusion process driven by HIV-1, we decided to synthesize soluble analogs of GalCer with the aim to develop a new class of anti-HIV-1 agents that could neutralize HIV-1 infection through masking of the V3 loop. We describe a short route, in three steps, for the synthesis of soluble analogs of GalCer, using unprotected lactose as the starting sugar. The analogs were prescreened in an assay based on the interaction between a V3 loop-derived synthetic peptide and [3H]suramin, a polysulfonyl compound displaying high affinity for the V3 loop. One of the soluble analogs, i.e. CA52(n15), strongly inhibited the binding of [3H]suramin to the V3 peptide, with an IC50 of 1.2 microM. This molecule was also able to inhibit [3H]suramin binding to recombinant gp120 with similar activity. Using a competition enzyme-linked immunosorbent assay with highly specific anti-gp120 monoclonal antibodies, the region recognized by CA52(n15) could be mapped to amino acids 318-323, which corresponds to the highly conserved consensus motif GPGRAF. Interestingly, the region recognized by suramin, i.e. IQRGP-R-F, was partially overlapping this motif. CA52(n15) was able to inhibit HIV-1-induced cell fusion as well as HIV-1 entry into both CD4(+) and CD4(-)/GalCer+ cells. A structure-activity relationship study showed that: (i) the antiviral activity of soluble analogs of GalCer correlates with V3 loop binding, and (ii) the hydrophobic moiety of the molecule plays an important role in this activity. Taken together, these data show that synthetic analogs of GalCer can inhibit HIV-1 entry into both CD4(-) and CD4(+) cells through masking of the V3 loop.

Analysis of N-acyl aminonaphthalene sulphonic acid derivatives with potential anti-human immunodeficiency virus activity by thin-layer chromatography and flame ionization detection

A method for checking the purity of N-acyl aminonaphthalene disulphonic acid derivatives was required for a systematic study of the anti-human immunodeficiency virus activity of these agents. We describe the use of thin-layer chromatography and flame ionization detection for the separation of these compounds, which are difficult to analyse by conventional methods. All the samples were prepared in methanol solutions (1 microliter) containing 5 micrograms of aminonaphthalene derivative. These samples were applied to each type SIII Chromarod by a single injection and developed with pure methanol or a methanol-chloroform-ammonium hydroxide (35:55:10, v/v/v) solvent system.