MOLECULAR-CLONING AND CHARACTERIZATION OF THE MAJOR ALLERGEN MYR P-IIFROM THE VENOM OF THE JUMPER ANT MYRMECIA-PILOSULA - MYR P-I AND MYR P-II SHARE A COMMON PROTEIN LEADER SEQUENCE

A major allergen Myr p II of the Australian jumper ant Myrmecia pilosu la has been cloned, immunocharacterized and nucleotide sequenced. An o pen reading frame of 225 bases was identified and found to encode a de duced amino acid sequence of 75 residues which contained a typical hyd rophobic peptide leader sequence. Expressed fusion proteins of Myr p I I in both phage and plasmid vectors bind high levels of ant venom-spec ific IgE and the expressed clones are recognised by 35% of ant venom-a llergic individuals. IgE antibodies that recognise the expressed clone have been shown to recognise IgE-binding bands in blots of native ven om after separation by SDS-PAGE. The amino acid sequence of Myr p II s hares close structural homology with the other major jumper ant allerg en Myr P I, differing by only three amino acids in the first 47 residu es of both sequences. However, N-terminal analysis of IgE-binding band s derived from Tricine-SDS-PAGE gel blots indicates that both Myr p I and Myr p II undergo extensive post-translational proteolytic processi ng to unique peptides of 45 and 27 residues, respectively.