• KSBB Journal
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• v.13 no.4
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• pp.369-377
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• 1998

To analyze the unique aspects of biomolecular processing for monoclonal antibody (MAb) production and secretion, the simple working model based on 3-compartment (endoplasmic reticulum, Golgi apparatus, and extracellular medium) was developed. Based on in vitro MAb assembly experimental results, the kinetic model for MAb assembly in the endoplasmic reticulumn was proposed. The dynamics of MAb assembly and secretion was simulated using methematica program. According to the simulation results, the proposed 3-compartment model provides an efficient means to predict the specific MAb productivity as well as intracompartmental concentrations of MAb in endoplasmic reticulum, Golgi apparatus, and extracellular compartment model. In vivo profiles of MAb intermediates gave good agreements with the simulation profiles predicted by the intracellular compartment model. Furthermore, results of such analysis can help in directing the control strategy for optimum biomolecular processing in a mammalian cell culture system.

• Journal of Life Science
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• v.23 no.3
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• pp.347-354
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• 2013

Innate immunity is the ability to differentiate infectious agents from self. The innate immune system is comprised of a complicated network of recognition and effector molecules that act together to protect the host in the early stage of an infectious challenge. Mannose-binding lectin (MBL or mannose-binding protein, MBP) belongs to the family of $Ca^{2+}$-dependent lectins (C-type lectin with a collagen-like domain), which are considered an important component of innate immunity. While it is associated with increased risk and severity of infections and autoimmunity, the most frequent immuno-deficiency syndrome was reported to be low MBL level in blood. Deficiency of human MBL is caused by mutations in the coding region of the MBL gene. Rat homologue gene of human MBL gene was used to study functions of wild type and mutant MBL proteins. Although extensive studies have yielded the structural information of MBL, the functions of MBL, especially mutant MBL, still require investigation. We previously reported the cloning of rat wild-type MBL gene and the production of a truncated form of MBL protein and its antibody. Here, we present the cloning of mutant MBL cDNA in collagen-like domain (R40C, G42D, and G45E) using site-directed mutagenesis and differential behaviors of wild type and mutant MBL in cells. The major difference between wild type and mutant MBL was that while wild type MBL was secreted, mutant MBL was inhibited for secretion, retained in endoplasmic reticulum, and still functioned as a lectin.

• KSBB Journal
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• v.13 no.5
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• pp.585-592
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• 1998

The effect of intracellular Ca2+ level on the hybridoma cell growth and monoclonal antibody(MAb) production was examined. For the manipulation of intracellular Ca2+ concentration, the cells were treated with A23187, ryanodine, and thapsigargin at about 1x106 cells/mL. The treated cells were recultivated by using the Iscove's Modified Dulbecco's Medium(MDM) containing 1.49mM CaCl2. The ryanodine-treated cells showed better cell growth, MAb concentration, and specific MAb productivity than others. In comparison with control, the maximum cell concentration, MAb concentration, and specific MAb productivity were increased by 40.6%, 48.1% and 83.3%, respectively. Confocal microscopic images of Fura-2/AM loaded cells indicate that the increase in intracellular Ca2+ level can enhance the MAb productivity by allowing the calcium influx into the endoplasmic reticulumn.