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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 diagnostic oligonucleotide microarray for subtyping of human and animal influenza A viruses (IAVs) was developed. We proposed a simple method of the fluorescent labeling of genomic segments of all known IAVs subtypes, the composition of the hybridization buffer, as well as the software of the data processing. 48 IAVs strains of different subtypes were analyzed using our microarray. All of them were identified, while 45 of 48 strains were unambiguously subtyped.

Alternative expression of ceruloplasmin (Cp) gene, whose product, blue multicopper ferroxidase, is a neuron survival factor, was studied in the current work. Computer analysis showed that Cp-mRNA isoform, coding for 109 kDa polypeptide, can be formed as a result of the transcription from the alternative promoter in 3'-region of intron 2 of rat Cp gene. Alternative Cp form starts with 25 amino acid residues sequence, coded with intron 2 region. It is followed by amino acid sequence of the main Cp isoform starting from Gly 113. In silico data were experimentally confirmed using RT-PCR. It was demonstrated that the predicted mRNA was generally localized in liver and brain cells of adult rats. Direct sequencing of the obtained PCR-product showed the entire coincidence of the real and predicted mRNAs. It was in vitro showed that approximately 110 kDa Cp-like protein was completed and accumulated in the absence of mitochondria. This protein is transferred into the isolated mitochondria in the reconstructed system. Transport is energy-dependent, it is not accompanied with the shortening of Cp polypeptide length and needs the presence of cytosolic factors. Probably import is determined by the inner protein mitochondria import signal with amino acid sequence KVVYREFTDSTFRE, located in 756-769 region of mature Cp. Possible role of Cp in iron metabolism in mitochondria is under discussion.

Using immunoblotting method it was found out that ceruloplasmin (Cp) polypeptides are revealed in mitochondria of rats, isolated from brain, liver, testicles and mammary gland. Cp is localized in matrix and inner membranes of mitochondria. Its molecular weight corresponds to the non-glycosilated form of the protein. Computer analysis did not reveal any sequences homologous to the signal peptide for mitochondria protein import (SPMPI) in the rat chromosomal Cp gene. However the analysis of homologous to Cp sequences, presented in databases, detected SPMPI in the human processed Cp pseudogene. Cp pseudogene region of 984 nucleotides long is translated in the only reading frame to the polypeptide of 328 a.a. long including 66 a.a of SPMPI at N-terminus. The predicted protein with the exception of SPMPI is identical to the corresponding Cp fragment at 92%, it has 20 amino acid substitutions, 8 of which are significant. His-X-His motif, typical for copper containing ferroxidases, is located in the centre of a molecule. Potential copper-binding site appears as a result of proline to histidine substitution at 923 position along Cp sequence. The product of Cp pseudogene transcription was detected in the human cultured cells of HepG2 and HuTu 80 cell lines using RT-PCR strategy. 30 kDa polypeptide that interacts with human Cp antibodies was found in mitochondria of HuTu 80 cells. The possible biological role of mitochondrial Cp is under discussion.