Monoclonal antipeptide antibodies recognize IL-3 and neutralize its bioactivity in vivo.
Mixtures of synthetic peptides corresponding to segments of murine IL-3 or synthetic IL-3 were used to raise murine mAb. Several mAb able to recognize synthetic IL-3 were obtained, two of which exhibited significant cross-reactivity with native IL-3 as shown by precipitation of biosynthetically 35S-labeled IL-3 and their effectiveness as affinity reagents for the purification of IL-3 from conditioned medium. The amino acid sequence recognized by the two mAb was determined by using synthetic peptide segments of IL-3. In both cases binding of the mAb to synthetic IL-3 was inhibited best with a hexapeptide corresponding to the amino acid residues 130-135 of IL-3, although the mAb differed in other characteristics. Neither mAb neutralized IL-3 bioactivity in vitro. However, we observed that in vivo administration of one mAb abrogated the increase in splenic mast cells and their precursors that normally occurred in mice bearing a s.c. IL-3-producing tumor, WEHI-3B.
Ziltener
H J
HJ
Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Victoria, Australia.
Clark-Lewis
I
I
Fazekas de St Groth
B
B
Orban
P C
PC
Hood
L E
LE
Kent
S B
SB
Schrader
J W
JW
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D003429:Cross Reactions; D005260:Female; D007114:Immunization; D007377:Interleukin-3 / Q000276:immunology*; D007942:Leukemia, Experimental / Q000473:pathology; D008407:Mast Cells / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D009500:Neutralization Tests; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000276:immunology; D013154:Spleen / Q000473:pathology
D000911:Antibodies, Monoclonal; D007377:Interleukin-3; D010446:Peptide Fragments