Development of the Bispecific Antibody in Fab-scFv Format Based on an Antibody to Human Interferon Beta-1 and Antibody to HER2 Receptor

Russian Journal of Bioorganic Chemistry - The development of new therapies for malignant tumors is an urgent task. Currently, the humanized antibody trastuzumab is considered the “gold...     

Studies on the influence of different designs of eukaryotic vectors on the expression of recombinant IgA

Production and application of therapeutic monoclonal antibodies are second only to vaccines in the world pharmaceutical market. The most common therapeutic antibodies are monoclonal antibodies (mAbs) of the IgG isotype that are produced in eukaryotic CHO cells. In recent years, there has been a considerable interest in developing treatment medications based on IgA antibodies, which can have a wide range of effector functions on human mucous membranes. To study the expression level of immunoglobulin A (IgA) in mammal cells, we designed a set of bipromoter (CMV and EF1α) vectors. The vectors contain gene fragments that encode the heavy chain variable domain (VH) and the light chain variable domain (VL) of the human monoclonal antibody FI6v3 against the hemagglutinin of influenza virus A. They also contain gene fragments that encode the light chain (kappa type) constant domain and the heavy chain constant domain of the human antibody IgA1. The expression vectors differed in the orientation of the promoters and the presence or absence of introns. Two variants of the full-length light and heavy chains were cloned into a eukaryotic expression vector in head-to-head and head-to-tail orientations. The resulting plasmids were transfected into CHO-DG44 and HEK-293T cells. The antibody expression level for the stable transfection of CHO-DG44 and HEK-293T cell cultures was determined by ELISA. The results of the experiments showed that the expression of FI6v3-IgA1 antibodies significantly increased when eukaryotic cells were transfected with the plasmid pBiPr-ABIgA1FI6-Iht in which the heavy chain of IgA1 contains introns and the promoters are arranged head-to-tail.     

In vitro Antiviral Activity of Recombinant Antibodies of IgG and IgA Isotypes to Hemagglutinin of the Influenza A Virus

Seasonal and highly infectious strains of the influenza A and influenza B viruses cause millions of cases of severe complications in elderly people, children, and patients with immune diseases each year. Immunoglobulin A (IgA), which is an active component of humoral immunity, can prevent the spread of the virus in the upper respiratory tract. The preparation and study of the properties of recombinant virus-specific IgA could be an important approach to finding new means of preventing and treating influenza. Based on CHO DG44 cells, we developed stable monoclonal cell lines that produce monomeric and dimeric antibodies FI6-IgA1 and FI6-IgA2m1 to hemagglutinin (HA) of the influenza A virus. When studying the productivity, growth, and stability of the obtained clones, we found that the dimeric form of antibodies of IgA1 isotype is superior to other forms. The dimeric form of IgA antibodies plays a key role in mucosal immunity. Recognizing the prospects of using dimeric IgA as prophylactic and therapeutic mucosal drugs for viral infections, we studied their virus-neutralizing and antiviral activities on MDCK cell culture and compared them with the antibodies of the IgG1 isotype. This study presents the data on antiviral and virus-neutralizing activities of the FI6-IgA1 dimers to seasonal and highly infectious strains of influenza A virus.     

The Development and Inmmunochemical Properties of the Dimer of Immunoglobulin A Specific to the Influenza Virus A Hemagglutinin

We obtained dimeric forms of IgA1- and IgA2m1-isotypes of FI6 antibody broadly specific to hemagglutinins of different subtypes of influenza A virus. It was shown that the dimers of IgA1 isotype are characterized by a higher antigen-binding activity compared to the IgA2m1 dimers. The affinity of IgA1 dimers to the strains of the H1N1 subtype is higher than that of the H3N2 subtype, which correlates with the properties of the parental human FI6 antibody.