A monoclonal antibody to the NH2-terminal segment of human IFN-gamma selectively interferes with the antiproliferative activity of the lymphokine
Caruso, A.; Tiberio, L.; De Rango, C.; Bonfanti, C.; Flamminio, G.; Gribaudo, G.; Monti, E.; Viani, E.; Manca, N.; Garotta, G.
Journal of Immunology 150(3): 1029-1035
1993
ISSN/ISBN: 0022-1767 PMID: 8423329 Document Number: 418378
To gain more information about the relationship between the structure of IFN-gamma and its activity, a peptide corresponding to a hydrophilic peak between amino acids 4 and 16 was used to immunize mice and generate mAb. mAb IGMB-15 reacts to both native and rIFN-gamma and neutralizes the antiproliferative activity of IFN-gamma without affecting its antiviral activity or its ability to up-regulate HLA-DR Ag expression. Moreover, we observed that mAb IGMB-15 was unable to inhibit the binding of radiolabeled IFN-gamma to its cellular receptor. These findings show that the NH-2-terminal region may somehow be involved in the biologic activity of IFN-gamma. Besides, the capability of mAb IGMB-15 to inhibit the antiproliferative but not the antiviral activity of IFN-gamma in the same cell (HEp-2) suggests the presence of different elements involved in signal transduction, which may account for the multiple activities of the lymphokine.