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Problem Galectin-3 is a β-galactoside binding protein with immunomodulatory properties and exerts its extracellular functions via interactions with glycoconjugate ligands. Therefore, to elucidate the function of galectin-3, binding ligands in human seminal plasma were investigated. Method of Study Galectin-3 binding proteins were isolated from seminal plasma by affinity chromatography, and candidate ligands were identified by MS/MS. Biochemical methods were used to characterize the ability of galectin-3 to bind its ligands. Results Identified galectin-3 ligands included CD13, MUC6, PAP, PSA and ZAG. 1D and 2D electrophoretic analysis of seminal plasma demonstrated that CD13, PAP, PSA, and ZAG immunoreactivity co-migrated with galectin-3-reactive protein bands and spots at expected molecular weights and pIs. Inhibition assays indicated that CD13, PSA, PAP, and ZAG, interact with galectin-3 in a protein-carbohydrate manner. Conclusion The galectin-3 binding ligands identified in this study indicate multiple roles for galectin-3 in the reproductive and immunological functions of seminal plasma.

Cytotoxic T lymphocytes (CTL) specific for human immunodeficiency virus type 1 (HIV-1) are thought to play an important role in controlling HIV-1 infection. HIV-1-specific CTL are readily demonstrated in unstimulated peripheral blood mononuclear cells (PBMC) of HIV-infected adults but less frequently in PBMC from vertically infected children. HIV-1-specific CTL lines were derived from a long-term survivor of vertical HIV-1 infection using PBMC stimulated with a CD3-specific monoclonal antibody and interleukin-2; these lines had Gag- or reverse transcriptase (RT)-specific cytotoxicity. Cytotoxicity was restricted by major histocompatibility complex class I antigen and blocked by antibody to the T cell receptor complex. Fluorescence-activated cell sorting analysis demonstrated their phenotype to be CD3+CD4-CD8+. Unstimulated PBMC from this patient had no detectable HIV-1-specific cytotoxicity when tested against autologous HIV-1 envelope-, Gag-, or RT-expressing target cells. Thus, this child with vertically acquired HIV-1 infection likely has HIV-1-specific CTL precursors despite the absence of circulating, activated HIV-1-specific CTL.