Biological properties of a recombinant human immunoglobulin epsilon-chain fragment.

AUTOR(ES)

Ishizaka, T

RESUMO

A recombinant human immunoglobulin epsilon-chain gene expression product (rFc epsilon) was compared with a human E myeloma protein in the affinity for epsilon-chain Fc fragment receptors (Fc epsilon R) on cultured human basophils. The association-dissociation kinetics of the rFc epsilon-Fc epsilon R interaction are indistinguishable from that of E myeloma protein, indicating that rFc epsilon and IgE have identical affinity for the receptors. The recombinant gene product sensitizes cultured basophils for anti-IgE-induced histamine release. A dose-response curve of histamine release indicates that the gene product is equally efficient in transducing the signal for degranulation as the natural IgE. Both the rFc epsilon and IgE lost the affinity for Fc epsilon R by heating at 56 degrees C. Upon renaturation by passage through a solution of 6 M guanidine hydrochloride, rFc epsilon recovered both the affinity for Fc epsilon R and the original CD spectra. On the other hand, renaturation of heat-denatured IgE largely restored optical activity above 250 nm but restored neither the affinity for Fc epsilon R nor the CD spectrum below 220 nm. The results suggest that either the amino acid sequence or the carbohydrate present in the myeloma protein, but not the rFc epsilon, may interfere with refolding of the receptor-binding structures.

Documentos Relacionados

• Properties of a human immunoglobulin epsilon-chain fragment synthesized in Escherichia coli.
• Blocking of passive sensitization of human mast cells and basophil granulocytes with IgE antibodies by a recombinant human epsilon-chain fragment of 76 amino acids.
• A recombinant immunotoxin containing a disulfide-stabilized Fv fragment.
• Cloning of human immunoglobulin epsilon chain genes: evidence for multiple C epsilon genes.
• Expression of a biologically active fragment of human IgE epsilon chain in Escherichia coli.