An agent comprising: a) a peptide or a peptide analog selected from the group consisting of: i) a peptide or peptide analog comprising or consisting of an amino acid sequence selected from the group consisting of KPLAEIDSIELSYGIK (SEQ ID NO: 136), VDTYDGGISVVYGLR (SEQ ID NO: 138), KCLAECDSIELSYGIK (SEQ ID NO: 141), KPLAEDISIELSYGIK (SEQ ID NO: 145), KPLAEIGDIELSYGIK (SEQ ID NO: 146), KPLAEIDSIELTYGIK (SEQ ID NO: 149), KPLAEIDGIELSYGIK (SEQ ID NO: 150), KPLAEIGSIELSYGIK (SEQ ID NO: 152), KGLAEIDSIELSYGIK (SEQ ID NO: 153), KPLAGIDSIGLSYGIK (SEQ ID NO: 154); CLAEIDSC (SEQ ID NO: 142), CFKPLAEIDSIECSYGIK (SEQ ID NO: 143), KPLAEGDIELSYGIK (SEQ ID NO: 147), KPLAEIELSYGIK (SEQ ID NO: 148), KCLAEIDSCELSYGIK (SEQ ID NO: 155), CFKPLAEIDSIEC (SEQ ID NO: 156), VDTYDGDGSVVYGLR (SEQ ID NO: 139), VDVPEGDISLAYGLR (SEQ ID NO: 157), LDGLVRAYDNISPVG (SEQ ID NO: 158), GDPNGDISVVYGLR (SEQ ID NO: 159), VDVPNGDISLAYRLR (SEQ ID NO: 160), VDVPEGDISLAYRLR (SEQ ID NO: 161), V(beta-D)TYDGDISVVYGLR (SEQ ID NO:167), VDTY(beta-D)GDISVVYGLR (SEQ ID NO: 168), and VDTYDG(beta-D)ISVVYGLR (SEQ ID NO:169); ii) a peptide or peptide analog consisting of the amino acid sequence GDPNDGRGDSVVYGLR (SEQ ID NO: 137); and iii) a peptide or peptide analog comprising or consisting of the amino acid sequence KPLAEIDGIELTYGIK (SEQ ID NO: 151), wherein the peptide or peptide analog comprises no more than 25 amino acid residues; b) a polynucleotide encoding upon expression, the peptide of a); c) a vector comprising the polynucleotide of b); or d) a cell comprising the polynucleotide of b), or the vector of c). a) a peptide or a peptide analog selected from the group consisting of: i) a peptide or peptide analog comprising or consisting of an amino acid sequence selected from the group consisting of KPLAEIDSIELSYGIK (SEQ ID NO: 136), VDTYDGGISVVYGLR (SEQ ID NO: 138), KCLAECDSIELSYGIK (SEQ ID NO: 141), KPLAEDISIELSYGIK (SEQ ID NO: 145), KPLAEIGDIELSYGIK (SEQ ID NO: 146), KPLAEIDSIELTYGIK (SEQ ID NO: 149), KPLAEIDGIELSYGIK (SEQ ID NO: 150), KPLAEIGSIELSYGIK (SEQ ID NO: 152), KGLAEIDSIELSYGIK (SEQ ID NO: 153), KPLAGIDSIGLSYGIK (SEQ ID NO: 154); CLAEIDSC (SEQ ID NO: 142), CFKPLAEIDSIECSYGIK (SEQ ID NO: 143), KPLAEGDIELSYGIK (SEQ ID NO: 147), KPLAEIELSYGIK (SEQ ID NO: 148), KCLAEIDSCELSYGIK (SEQ ID NO: 155), CFKPLAEIDSIEC (SEQ ID NO: 156), VDTYDGDGSVVYGLR (SEQ ID NO: 139), VDVPEGDISLAYGLR (SEQ ID NO: 157), LDGLVRAYDNISPVG (SEQ ID NO: 158), GDPNGDISVVYGLR (SEQ ID NO: 159), VDVPNGDISLAYRLR (SEQ ID NO: 160), VDVPEGDISLAYRLR (SEQ ID NO: 161), V(beta-D)TYDGDISVVYGLR (SEQ ID NO:167), VDTY(beta-D)GDISVVYGLR (SEQ ID NO: 168), and VDTYDG(beta-D)ISVVYGLR (SEQ ID NO:169); ii) a peptide or peptide analog consisting of the amino acid sequence GDPNDGRGDSVVYGLR (SEQ ID NO: 137); and iii) a peptide or peptide analog comprising or consisting of the amino acid sequence KPLAEIDGIELTYGIK (SEQ ID NO: 151), wherein the peptide or peptide analog comprises no more than 25 amino acid residues; i) a peptide or peptide analog comprising or consisting of an amino acid sequence selected from the group consisting of KPLAEIDSIELSYGIK (SEQ ID NO: 136), VDTYDGGISVVYGLR (SEQ ID NO: 138), KCLAECDSIELSYGIK (SEQ ID NO: 141), KPLAEDISIELSYGIK (SEQ ID NO: 145), KPLAEIGDIELSYGIK (SEQ ID NO: 146), KPLAEIDSIELTYGIK (SEQ ID NO: 149), KPLAEIDGIELSYGIK (SEQ ID NO: 150), KPLAEIGSIELSYGIK (SEQ ID NO: 152), KGLAEIDSIELSYGIK (SEQ ID NO: 153), KPLAGIDSIGLSYGIK (SEQ ID NO: 154); CLAEIDSC (SEQ ID NO: 142), CFKPLAEIDSIECSYGIK (SEQ ID NO: 143), KPLAEGDIELSYGIK (SEQ ID NO: 147), KPLAEIELSYGIK (SEQ ID NO: 148), KCLAEIDSCELSYGIK (SEQ ID NO: 155), CFKPLAEIDSIEC (SEQ ID NO: 156), VDTYDGDGSVVYGLR (SEQ ID NO: 139), VDVPEGDISLAYGLR (SEQ ID NO: 157), LDGLVRAYDNISPVG (SEQ ID NO: 158), GDPNGDISVVYGLR (SEQ ID NO: 159), VDVPNGDISLAYRLR (SEQ ID NO: 160), VDVPEGDISLAYRLR (SEQ ID NO: 161), V(beta-D)TYDGDISVVYGLR (SEQ ID NO:167), VDTY(beta-D)GDISVVYGLR (SEQ ID NO: 168), and VDTYDG(beta-D)ISVVYGLR (SEQ ID NO:169); ii) a peptide or peptide analog consisting of the amino acid sequence GDPNDGRGDSVVYGLR (SEQ ID NO: 137); and iii) a peptide or peptide analog comprising or consisting of the amino acid sequence KPLAEIDGIELTYGIK (SEQ ID NO: 151), wherein the peptide or peptide analog comprises no more than 25 amino acid residues; b) a polynucleotide encoding upon expression, the peptide of a); c) a vector comprising the polynucleotide of b); or d) a cell comprising the polynucleotide of b), or the vector of c).