Pharmacological activity of chemically modified subfragment from human serum IgG. XIV. Inhibitory effect of carboxamide-methylated light chain (G1L) on tyrosine phosphorylation and tumor necrosis factor-alpha production from murine macrophages stimulated by lipopolysaccharide.

Carboxamide-methylated light chain (G1L) from human serum IgG inhibited the secretion of tumor necrosis factor (TNF-alpha), one of the inflammatory cytokines, from adherent splenocytes and thioglycolate-induced peritoneal macrophages. The inhibition of TNF-alpha secretion by G1L was associated with disappearance of tyrosine phosphorylation on about 40 kDa protein when thioglycolate-induced peritoneal macrophages were stimulated with lipopolysaccharide (LPS). It is possible that this G1L anti-inflammatory activity occurs through the blockage of the phosphorylation of about 40 kDa protein.