<P>PROBLEM TO BE SOLVED: To provide a retro-inverso peptide which is derived from interleukin-3 (IL-3), comprises a specific sequence, has activities similar to that of the native parent protein, and also has neurotrophic activity. <P>SOLUTION: In one aspect of this preferred embodiment, at least one basic charged amino acid of the sequence is replaced with a different basic charged amino acid. In another aspect of this preferred embodiment, at least one acidic charged amino acid of the sequence is replaced with a different acidic charged amino acid. Advantageously, at least one non-polar amino acid of the sequence is replaced with a different non-polar amino acid. Preferably, at least one non-charged amino acid of the sequence is replaced with a different non-charged amino acid. In another aspect of this preferred embodiment, at least one aromatic amino acid of the sequence is replaced with a different aromatic amino acid. <P>COPYRIGHT: (C)2011,JPO&INPIT 
RETRO-INVERSO PEPTIDE DERIVED FROM INTERLEUKIN-3