The complete guide to the structure of bispecific antibodies

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The complete guide to
The complete guide to
the structure of bispecific antibodie
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What Is Bispecific Antibody?
Bispecific antibodies can recognize and bind two
different antigens separately, so it can connect
immune cells, viral molecules, etc. to tumor
cells, thereby enhancing the killing effect on
target cells, and it can also combines different
antigens on the same tumor cell to enhance its
binding specificity, thereby reducing side
effects such as off-target toxicity. This
bifunctional recombinant antibody has a higher
therapeutic effect as a drug for treating tumors
than a monoclonal antibody.
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CONTENTS
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Bispecific Antibody with C Region
The structure of this constant region-containing
bispecific antibodies is very similar to that of
a general antibody structure, and is also called
a bispecific antibody of an IgG-like structure.
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Bispecific Antibody with C Region
It differs from the general IgG antibody and
non-IgG-like structure of bispecific antibodies
in which it has both bispecificity and the
corresponding function of the constant region,
and its relatively large molecular weight, so it
has higher stability and longer half-life.
And also it is beneficial for the purification of
antibody products, but its tissue permeability is
also relatively low. Different types can be
formed depending on the different domains of the
fusion, such as scFv-Fc antibody, Minibody,
Bi-nanobody and the like.
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The ScFv-Fc antibody (100-105 k) is a class of
bispecific antibodies containing both scFv and Fc
segments. The scFv segment can be fused to CH2
and CH3 of human IgG and can also be fused to the
hinge region. Studies have shown that it has a
certain effect in the treatment of tumors, and
this antibody also has certain small molecular
characteristics, so it is convenient to use gene
transfer technology to maintain its body content.
Johnson et al. detected an endogenous and
sustained antibody expression by intramuscular
injection of an adenoviral vector encoding an
anti-monkey immunodeficiency virus scFv-Fc
antibody (4L6) into the body.
Bispecific Antibody with C Region
Minibody (80 k) is also a bispecific antibodiy
containing the C region by fusing the scFv
segment of the antibody molecule to the
C-terminus of the CH3 domain of human IgG. In
clinical studies, antibodies of this structure
are used to treat cancer patients, and positron
emission tomography (PET) or computed tomography
(CT) is used to monitor the patient's tumor
development status, confirming that it is indeed
effective.
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Bispecific Antibody without C Region
Bispecific antibody without C region contain only
variable segments of antibody molecules, and thus
their structures differ greatly from those of
general antibodies, and can also be referred to
as bispecific antibodies of non-IgG-like
structures.
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2. Bispecific Antibody without C Region
However, low molecular mass also results in a
short half-life in plasma, so the use of this
drug for anti-tumor therapy requires continuous
intravenous infusion of a constant-flow pump or
in a sustained-release dosage form.
It retains only the fragments that bind to the
antigen, and the relative molecular mass is
usually small, so it has a high tissue
permeability and easily penetrates into the tumor
tissue through the blood vessels.
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Studies have shown that tandem scFv fragments
have the ability to recruit effector lymphocytes,
such as anti-CD3 and anti-CD19. Bispecific T cell
Engagers have produced good results in the
clinical treatment of several different B-cell
lymphomas. At present, three kinds of Bispecific
T cell Engagers have been applied to solid tumor
treatment in preclinical studies. They have
localized different tumor antigens (EpCAM, CEA
and PSMA) and achieved some effects.
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Reference https//www.creative-biolabs.com/bsab/