Isolation and Characterization of Recombinant Variable Domain of Heavy Chain Anti-idiotypic Antibodies Specific to Aflatoxin B_1

Some unique subclasses of Camelidae antibodies are devoid of the light chain, and the antigen binding site is comprised exclusively of the variable domain of the heavy chain （VHH）. The recombinant VHHs have a high potential as alternative reagents for the next generation of immunoassay. In particular, they might be very useful for molecular mimicry. The present study demonstrated an alpaca immunized with the F（ab＇）z fragment of anti-aflatoxin B1 mAb and developed an important anti-idiotypic （anti-ld） responses. Antigen-specific elution method was used for panning private anti-ld VHHs from the constructed alpaca VHH library. The selected VHHs were expressed, renatured, purified, and then identified by a competitive enzyme-linked immunosorbent assay （ELISA）. Our findings indicated that the VHH would be an alternative tool for haptens mimicry studies.

Fusion protein of single-chain variable domain fragments for treatment of myasthenia gravis

Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pastoris. The afifnity of scFv-human serum albumin fusion protein to bind to acetylcholine receptor at the neuromuscular junction of human intercostal muscles was detected by immunolfuorescence staining. The ability of the fusion protein to block myas-thenia gravis patient sera binding to acetylcholine receptors and its stability in healthy serum were measured by competitive ELISA. The results showed that the inhibition rate was 2.0-77.4%, and the stability of fusion protein in static healthy sera was about 3 days. This approach suggests the scFv-human serum albumin is a potential candidate for speciifc immunosuppressive therapy of myasthenia gravis.

An approximation for the boundary optimal control problem of a heat equation defined in a variable domain

In this paper, we consider a numerical approximation for the boundary optimal control problem with the control constraint governed by a heat equation defined in a variable domain. For this variable domain problem, the boundary of the domain is moving and the shape of theboundary is defined by a known time-dependent function. By making use of the Galerkin finite element method, we first project the original optimal control problem into a semi-discrete optimal control problem governed by a system of ordinary differential equations. Then, based on the aforementioned semi-discrete problem, we apply the control parameterization method to obtain an optimal parameter selection problem governed by a lumped parameter system, which can be solved as a nonlinear optimization problem by a Sequential Quadratic Programming （SQP） algorithm. The numerical simulation is given to illustrate the effectiveness of our numerical approximation for the variable domain problem with the finite element method and the control parameterization method.

Binding Activity Difference of Anti-CD20 scFv-Fc Fusion Protein Derived from Variable Domain Exchange

Two novel engineered antibody fragments binding to antigen CD20 were generated by fusing a murine IgM-type anti-CD20 singie-chain Fv fragment （scFv） to the human IgG1 CH2 （i.e., Cγ2） and CH3 （i.e., Cγ3） domains with the human IgG1 hinge （i.e. Hγ）. Given the relationship between structure and function of protein, the 3-D structures of the two engineered antibody fragments were modeled using computer-aided homology modeling method. Furthermore, the relationship between 3-D conformation and their binding activity was evaluated theoretically. Due to the change of active pocket formed by CDRs, the HL23 （VH-Linker-VL-Hγ-Cγ2-Cγ3） remained its activity because of its preserved conformation, while the binding activity of the LH23 （VL-Linker-VH-Hγ-Cγ2-Cγ3） was impaired severely. Experimental studies by flow cytometry and fluorescence microscopy showed that HL23 possessed significantly superior binding activity to CD20-expressing target cells than LH23. That is to say, the order of variable regions could influence the binding activity of the fusion protein to CD20^＋ cell lines, which was in accordance with the theoretical results. The study highlights the potential relationship between the antibody binding activity and their 3-D conformation, which appears to be worthwhile in providing direction for future antibody design of recombinant antibody.

THE HYBRID PROBLEM OF FREE-SURFACE GRAVITY SPILLWAY FLOW TREATED BY VARIATIONAL PRINCIPLES WITH VARIABLE DOMAIN: POTENTIAL fUNCTION FORMULATION

Making full use of functional variations with variable domain for handling both the free surface and unknown part of the dam wall,a family of variational principles(VPs)for the hybrid(direct-inverse)problem of free surface spillway flow under gravity is formulated in terms of the potential function Φ.This theory offers new rational and versatile ways for dam de- sign and a sound theoretical basis for numerical solution,e.g.by the finite element method (FEM).

Multilinear Calder′on Zygmund operators on variableexponent Morrey spaces over domains

The boundedness of multilinear singular integrals of Calder′on-Zygmund type onproduct of variable exponent Lebesgue spaces over both bounded and unbounded domains areobtained. Further more, the boundedness for this type multilinear operators on product ofvariable exponent Morrey spaces over domains is shown in the paper.

The Analysis and Numerical Simulation of Dynamical Functions of the Transpiration Cooling Control System with Surface Ablation

This problem is a nonlinear control system with variable-domain distributed parameter. In this paper, the numerical simulation of the dynamic functions has been carried out by transforming this problem to a fixed-domain initial-boundary value problem, and the numerical results are obtained: (1) Thedistribution of temperature rises, the ablation amount and velocity of the thermal shield vary with the time; (2) The maximum ablating velocity, the time of the ablation beginning and ending related to thetranspiration quantity. This method succeeds in overcoming the difficulty brought up by variable domain.On the other hand, the critical transpiration quantity for the surface to start ablating, the maximum ablating velocity and time of the ablation ending are obtained theoretically.

Antibody-Like Phosphorylation Sites. Theme for Studies of Cancer, Aging and Evolution

Sequence similarities were found between protein and DNA sequences encoding certain part of conserved variable immunoglobulin domains (i.e. conserved IgV) and phosphorylation sites. Hypermutation motifs were then indicated in the majority of the corresponding non-IgV nucleotide sequences. According to database confirmations or double prediction of phosphorylation sites, 80% of the selected human and mouse IgV-related phosphorylation sites or their highly probable candidates exhibited substrate relationship to ataxia-telangiectasia-mutated kinase known as ATM. In accordance with literature data, inactivation of ATM by mutations can participate in the mechanisms of carcinogenesis, neurodegeneration and possibly also in aging. In agreement with this relationship, some of the selected IgV-/ATM-related segments formed molecules specifically involved in carcinogenesis. The selected IgV-related sequence segments were also similar to certain segments of higher plants containing immunoglobulin-like repeats and related regions. Bioinformatic analysis of some selected plant sequences then indicated the presence of catalytic domains composing serine/threonine/tyrosine receptor/receptor-like kinases, which are considered important structures for evolution of very early and part of later Ig-domain-related immunity. The analyzed conserved domain similarities also suggested certain interesting structural and phylogenic relationships, which need to be further investigated. This review in fact briefly summarizes the findings on the subject from the last twenty years.