Patent ID: 8029789

Claim:
A method of producing an immunoglobulin constant region, comprising: transforming E. coli with a recombinant expression vector including a nucleotide sequence encoding an E. coli signal sequence and a nucleotide sequence encoding an immunoglobulin constant region, without a variable region; culturing a resulting transformant in a medium to overexpress the immunoglobulin constant region in the cytoplasm of the transformant; and isolating the immunoglobulin constant region expressed by the transformant, wherein the signal sequence is a heat-stable enterotoxin II signal sequence, and wherein the immunoglobulin constant region is expressed in the cytoplasm in a water soluble form and is not secreted into the medium or the periplasmic space, and wherein the transformant is selected from the group consisting of E. coli BL21/pSTIIGICH1 3 (HM10935; Deposit No. KCCM-10600), BL21/pSTIIdCG1Fc (HM10927; Deposit No. KCCM-10588), BL21/pSTIIdCG1SFc (HM10928; Deposit No. KCCM-10589), BL21/pSTIIdCG1SFFc (HM10929; Deposit No. KCCM-10594), BL21/pSTIIG1Mo (HM10930; Deposit No. KCCM10595), BL21/pSTIIdCG4Fc (HM10932; Deposit No. KCCM-10597), BL21/pSTIIG4CH1 3 (HM10931; Deposit No. KCCM-10596), BL21/pSTIIG4Mo (HM10933; Deposit No. KCCM-10598), and BL21/pSTIIG4H K (HM10934; Deposit No. KCCM-10599).