• Molecules and Cells
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• v.20 no.1
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• pp.17-29
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• 2005

Therapeutic antibodies represent one of the fastest growing areas of the pharmaceutical industry. There are currently 19 monoclonal antibodies in the market that have been approved by the FDA and over 150 in clinical developments. Driven by innovation and technological developments, therapeutic antibodies are the second largest biopharmaceutical product category after vaccines. Antibodies have been engineered by a variety of methods to suit a particular therapeutic use. This review describes the structural and functional characteristics of antibody and the antibody engineering for the generation and optimization of therapeutic antibodies.

• Applied Microscopy
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• v.23 no.2
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• pp.84-96
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• 1993

This study was to investigate the effects of maternal diabetes on the lung tissue of the fetal rat using lectin histochemistry and electron microscope technique. Maternal diabetes was induced by intraperitoneal injection of streptozotocin (75 mg/kg the body weight) into pregnant Sprague-Dawley rats on the 7th day of gestation. Fetuses of streptozotocin induced diabetic rats exhibited delayed lung maturation and reduced air space. In lectin histochemistry, the binding of Maclura pomifera (MPA) to fetal lungs from diabetic mothers was reduced, but no significant changes in the bindings of Concanavalin A (Con A), Wheat germ agglutinin (WGA), Ricinus communis I (RCA I) and Griffonia simplicifolia (GSI-$B_4$) were noted. Because the MPA has affinity to terminal N-acetyl-D-galactosamine residues constantly linked O-glycosidically to serine or threonine, the present findings may indicates that maternal diabetes interfere with the processes of O-linked glycosylation in fetal rat lung.

• Proceedings of the Korean Society of Crop Science Conference
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• 2004.04a
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• pp.112-113
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• 2004

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.197-208
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• 2014

A novel protease gene from Bacillus gibsonii, aprBG, was cloned, expressed in B. subtilis, and characterized. High-level expression of aprBG was achieved in the recombinant strain when a junction was present between the promoter and the target gene. The purified recombinant enzyme exhibited similar N-terminal sequences and catalytic properties to the native enzyme, including high affinity and hydrolytic efficiency toward various substrates and a superior performance when exposed to various metal ions, surfactants, oxidants, and commercial detergents. AprBG was remarkably stable in 50% organic solvents and retained 100% activity and stability in 0-4 M NaCl, which is better than the characteristics of previously reported proteases. AprBG was most closely related to the high-alkaline proteases of the subtilisin family with a 57-68% identity. The secretion and maturation mechanism of AprBG was dependent on the enzyme activity, as analyzed by site-directed mutagenesis. Thus, when taken together, the results revealed that the halo-solvent-tolerant protease AprBG displays significant activity and stability under various extreme conditions, indicating its potential for use in many biotechnology applications.

• BMB Reports
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• v.34 no.6
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• pp.573-577
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• 2001

The mammalian heart is known to undergo significant mechanical changes during fetal and neonatal development. The objective of this study was to define the ontogeny of the ryanodine receptor/$Ca^{2+}$ release channel and SERCA that play the major roles in excitation-contraction coupling. Whole ventricular homogenates of fetal (F) (19 and 22 days in gestation), postnatal (N) (1 and 7 days postnatal), and adult (A) (5 weeks postnatal) Sprague-Dawley rat hearts were used to study [$^3H$]ryanodine binding and oxalate-supported $^{45}Ca^{2+}$ uptake. For the ryanodine receptor, the major findings were: (1) The ryanodine receptor density, as determined by maximal [$^3H$]ryanodine binding ($B_{max}$), increased 3 fold between the F22 and A periods ($0.26{\pm}0.1$ vs. $0.73{\pm}0.07$ pmoles/mg protein, p<0.01), whereas there was no significant change during the F22 and N1 development phases ($0.26{\pm}0.1$ vs. $0.34{\pm}0.01$). (2) Affinity of the ryanodine receptor to ryanodine did not significantly change, as suggested by the lack of change in the $K_d$ during the development and maturation. For SERCA, changes started early with an increased rate of $Ca^{2+}$ uptake in the fetal periods (F19: $8.1{\pm}1.1$ vs. F22: $19.3{\pm}2.2$ nmoles/g protein/min; p<0.05) and peaked by 7 days (N7) of the postnatal age ($34.9{\pm}2.1$). Thus, we conclude that the quantitative changes occur in the ryanodine receptor during myocardial development. Also, the maturation of the $Ca^{2+}$ uptake appears to start earlier than that of the $Ca^{2+}$ release.

• BMB Reports
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• v.33 no.2
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• pp.155-161
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• 2000

The saccharomyces cerevisiae Rad27, a structure-specific endonuclease for the okazaski fragment maturation has been known to interact genetically and biochemically with Dna2, an essential enzyme for DNA replication. In an attempt to define the significance of the interaction between the two enzymes, we expressed and purified both Dna2 and Rad27 proteins. In this report, Rad27 could not form a complex with Dna2 in the three different analyses. The analyses included glycerol gradient sedimentation, protein-column chromatography, and coinfection of baculoviruses followed by affinity purification. This is in striking contrast to the previous results that used crude extracts. These results suggest that the interaction between the two proteins is not sufficiently stable or indirect, and thus requires an additional protein(s) in order for Rad27 and Dna2 to form a stable physical complex. This result is consistent with our genetic findings that Schizosaccharomyces pombe Dna2 is capable of interacting with several proteins that include two subunits of polymerase $\delta$, DNA ligase I, as well as Fen-1. In addition, we found that the N-terminal modification of Rad27 abolished its enzymatic activity. Thus, as suspected, we found that on the basis of the structure determination, N-terminal methionine indeed plays an important role in the nucleolytic cleavage reaction.

• Journal of Microbiology
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• v.39 no.1
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• pp.49-55
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• 2001

We have developed four chicken hybridomas secreting monoclonal antibodies to induce a protective immune response against the chicken disease avian coccidiosis, caused by the intestinal parasite Eimeria acervulina. Huwever, since the amount of antibodies secreted from these hybridomas is too low or sometimes they lost their ability to produce antibodies, the hybridoma method is not satisfactory in the production of large amounts of chicken monoclonal antibodies. To bypass these problems, we applied the antibody engineering technology using polymerase chain reaction. We cloned and determined the sequences of variable domains of the four chicken monoclonal antibodies, namely, 2-1, 5D11, 13C8 and 8C3. The sequences comparison to germline sequences skewed that the gene con version mechanism might contribute to developing diversification of heavy and λ-light chains in chicken antibodies. Several pseudogene families regarded as donors in gene conversion were identified at each framework region and the complementarily determining region of λ-light chains. In addition, as expected, numerous changes of nucleotide sequences such as nucleotide substitution, insertion and deletion were found predominantly in complementarity determining regions, which are likely to be somatic hypermutations as a result of affinity maturation in antibody-producing cells.

• Journal of Veterinary Clinics
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• v.8 no.1
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• pp.1-10
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• 1991

The B-lymphocyte differentiation from committed B-cell progenitors to antibody-secreting cells was discussed. B-cell progenitors derived from hematopoietic stem cells undergo the rearrangement of immunoglobulin(Ig) gene. The earliest cells as B-cell precursors have cytoplasmic Is(${\mu}$ chain). The entire Is molecule is expressed on the surface after synthesis of L chain. The resting B cells(Go stage) stimulated by binding antigen via Ig-receptors are activated(G$_1$ stage) and followed by proliferation(S stage), coupled with further selection(affinity maturation. class switch). The production of antibody against a particular antigen depends on the activation of B cells with surface Is capable of reacting with that antigen. This process does not occur in isolation but is controlled by helper and suppressor T cells and antigen presenting cells(APC). The mechanism of T cell-dependent B-cell response for production of antibody is largely explained by the cell to cell cooperation and soluble helper factors of T cells. 1) The antigen specific B cells and helper T cells are linked by Is-receptors, leading to the delivery of helper signals to the B cells. 2) Helper T cells recognize the processed antigen-derived peptides with the MHC class II molecules(la antigen) and is stimulated to secrete B-cell proliferation and differentiation factors which activate B cells of different antigenic specificity. The two models are shown currently 1) At low antigen concentration, only the antigen-specific B cell binds antigen and presents antigen-derived peptides with la molecules to helper T cells, which are stimulated to secrete cytokines(IL-4, IL-5, etc.) and 2) At high antigen concentration, antigen-derived peptides are presented by specific B cells, by B cells that endocytose the antigens, as well as by APC Cytokines secreted from helper T cells also lead to the activation of B cells and even bystander B cells in the on- vironmment and differentiate them into antibody-secreting plasma cells.

• The Journal of Korean Society of Virology
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• v.29 no.3
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• pp.175-182
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• 1999

An attractive target for anti-herpes chemotherapy is the herpes simplex virus 1 (HSV-1) protease encoded by the UL26 gene. HSV-1 protease is essential for DNA packaging and virus maturation. To perform high throughput for potent inhibitors, the efficient production of larger amounts of highly purified enzyme and protease activity assay method must be established. In this report, expression in E. coli and purification of the protease gene of HSV-1 strain F was investigated. The protease gene was cloned pET28, and the nucleotide sequence of protease catalytic domain of HSV-1 compared strain F with other strains (KOS and CL101). In these results the F strain was different in base sequence. However, the amino acid sequence was identifical. The HSV-1 protease was purified with His-tagged affinity column. The analysis of HSV-1 protease activity was performed by high performance liquid chromatography.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.136-136
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• 1998

L-asparaginyl and L- aspartyl residues in proteins are subject to spontaneous degradation reactions generating isomerized and racemized aspartyl derivatives. Proteins containing L-isoaspartyl and D-aspartyl residues usually have altered structures and diminished biological activities. These residues can be recognized and be repaired to normal L-aspartyl residues by protein L-isoaspartyl methyltransferase(PIMT), which is present at high levels in testis. Although testicular PIMT have been shown to be involved in either sperm motility or sperm maturation, it may play an important role in the repair of damaged sperm proteins during the prolonged period of epididymal transport and storage. In the present study, as a initial step toward elucidating the function of protein carboxylmethylation in testis, we purified PIMT from porcine testicular cytosol as a momeric 27,000 Da species by ammonium sulfate precipitation, DEAE-sephacel chromatography, SAH-liganded affinity chromatography, and gel filtration chromatography. The optimum pH for the reaction was 6.0. $K_{m}$ values of the enzyme for the S-adenosyl-L-methionine (SAM), synthetic oligopeptide(VYP-L-isoD-HA) and histone type II-As were 1.0 ${\mu}$M, 33.2 ${\mu}$M and 276 ${\mu}$M respectively. Consequently, properties of the porcine testicular PIMT is similar to that of other mammalian PIMTs.