Galactose to ceramide linkage is essential for the binding of a polyclonal antibody to galactosyl ceramide

Innate and adaptive anti-HIV immune responses in the female reproductive tract

The mucosal surface of the female reproductive tract (FRT) is the primary site of transmission for a plethora of sexually transmitted infections, including human immunodeficiency virus (HIV), that represent a significant burden upon womens' health worldwide. However, fundamental aspects of innate and adaptive immune protection against HIV infection in the FRT are poorly understood. The FRT immune system is regulated by the cyclical changes of the sex hormones estradiol and progesterone across the menstrual cycle, which as we have hypothesized, leads to the creation of a window of vulnerability during the secretory stage of the menstrual cycle, when the risk of HIV transmission is increased. The goal of this review is to summarize the multiple levels of protection against HIV infection in the FRT, the contribution of different cell types including epithelial cells, macrophages, T cells, and dendritic cells to this, and their regulation by estradiol and progesterone. Understanding the unique immune environment in the FRT will allow for the potential development of novel therapeutic interventions such as vaccines and microbicides that may reduce or prevent HIV transmission in women.

Cross-reactivity of anti-galactocerebroside autoantibodies with a Trypanosoma brucei proteolipidic epitope

Pathogenic mechanisms of the demyelinating encephalopathy featuring the nervous phase of human African trypanosomiasis (HAT) are largely unknown. They might include autoimmune disorders. A variety of autoantibodies is detected during the disease and we have previously evidenced anti-galactocerebroside (GalC) antibodies in the serum and cerebrospinal fluid (CSF) from patients in the nervous stage (stage II) of HAT. We now show that anti-GalC antibodies recognize an antigen located on the parasite membrane and common to different strains of trypanosomes. By using affinity chromatography with a rabbit anti-GalC antiserum, a 52-kD proteolipid was isolated from the membrane of Trypanosoma brucei (T. b.) brucei AnTat 1.9, AnTat 1. 1E, and T. b. rhodesiense Etat 1.2/R and Etat 1.2/S. Antibodies directed against this antigen were found in the CSF from patients with nervous stage HAT. These CSF also contained anti-GalC antibodies and adsorption with the proteolipid decreased anti-GalC reactivity. Immunization of mice with this antigen induced the production of antibodies which cross-reacted with GalC but no protection from experimental infection with T. b. brucei. These data support the hypothesis that anti-GalC antibodies detected in the CSF from HAT patients might be induced by molecular mimicry with a parasite antigen.

Benzopurpurin and related compounds inhibit the binding of gp120 to galactosyl ceramide/sulfatide and infection of human immunodeficiency virus

In an attempt to find compounds capable of inhibiting the binding and infection by human immunodeficiency virus type 1 (HIV-1) in neural cells, we studied the effect of benzopurpurin and related compounds on the binding of gp120 to galactosyl ceramide (GalCer) and sulfatide. In this report, we show that the binding of gp120 to GalCer and sulfatide is inhibited by benzopurpurin and related compounds. These compounds also inhibit the binding and entry of HIV-1 to neural cell line, SK-N-MC. Binding studies indicate that benzopurpurin and related compounds bind to gp120. Studies involving related compounds indicate that the minimal structure required for the inhibition is two naphthalene rings with amine or sulfonic acids attached to a central biphenyl molecule by an azo group. This approach will be useful for screening of potential anti-HIV compounds.