Insertion of constant region domains of human IgG, into CD4-PE40 increases its plasma half-life

摘要: Abstract CD4-PE40 is a recombinant toxin containing the binding domain of CD4 and mutant form Pseudomonas exotoxin A from which cell has been removed. To increase serum half-life CD4-PE40, we have inserted various portions constant human IgG, into CD4-PE40. The constructs made include CD4-C H 2-PE40, 3-PE40, 1-C 2-PE40 2-C 3-PE40. fusion proteins were expressed purified E. coli. Insertion domains region IgG 1 did not alter cytotoxic activity CD4-PE40; all these molecules equally to cells expressing gp120 on their surface. However, there was marked in mean residence time CD4-Cn2-PE40 115min as compared 47 min for other also increased however, found longest circulation. One possible explanation plasma diminished susceptibility proteolysis. It that much more resistant proteolysis by trypsin than We proposed insertion C 2 covers up protease sensitive sites molecule, thereby making molecule less susceptible degradation. size reduced sensitivity proteases could both be responsible 2-PE40.