EXPRESSION OF A HYDROPHILIC SURFACE PROTEIN IN INFECTIVE STAGES OF LEISHMANIA-MAJOR

A family of differentially expressed genes from Leishmania major conta ins one sequence (Gene B) that encodes a novel, hydrophilic protein fo und on the surface of infective parasite stages. The 177-residue, acid ic Gene B protein is characterised by an amino acid repetitive element , comprising 45% of the total molecule, that is related to the cell-wa ll binding domain of protein A from Staphylococcus aureus. No identifi able signal peptide, membrane-spanning domain or consensus for glycosy lphosphatidylinositol anchor attachment to the cell surface is found e lsewhere in the deduced protein sequence. In vitro, the Gene B protein fractionates with the parasite cell surface glycoconjugates, lipophos phoglycan and the glycoinositolphospholipids. This protein is the firs t characterised surface peptide marker for infective stages of the Lei shmania life cycle.