The human immunodeficiency virus (HIV) is a retrovirus that has been in the focus of worldwide investigation and research for many years. The only glycosylated protein present in the envelope of HIV is glycoprotein gp120, which mediates the binding of the virus to the host cell. Gp120 itself is covered with a dense layer of glycans, which accounts for approximately 50% of its molecular mass. The majority of these glycans are N-glycans consisting mostly of high mannose structures and, to a lesser extent, complex structures. It was shown that infection, trans-infection, transmission and syncytia formation can be affected by altering the glycan motifs or mutating specific N-glycan sites on gp120. In this thesis, I was investigating the role of sialic acid in gp120 binding, syncytia formation and recognition by broadly neutralizing antibodies of HIV.
