Characteristics of Artificial Immunogens Containing Peptide Mimotopes of HIV-1 Epitopes Recognized by Monoclonal Antibodies 2F5 and 2G12

The paper describes construction of TBI-based recombinant proteins TBI-2F5 and TBI-2G12 that contain peptide mimotopes of HIV-1 epitopes recognized by broadly neutralizing antibodies 2F5 and 2G12, respectively. The capacity of the immunogens to induce neutralizing antibodies was evaluated. The sera of BALB/c mice immunized with recombinant proteins TBI, TBI-2F5, and TBI-2G12 neutralized HIV-1 env-pseudoviruses. Moreover, pooled serum from mice immunized with TBI-2F5 and TBI-2G12 neutralized env-pseudoviruses of HIV-1 subtype B more effectively than individual sera.

[The impact of the antibody 2F5 biotinylation on the selection of the peptides from combinatorial phage library]

The impact of monoclonal antibodies (mAb) biotinylation on the output and the repertoire of selected peptides in the biopanning procedure were tested. A comparative analysis of the peptides selected from phage library using the biotinylated and non-biotinylated mAb 2F5 was performed. It was shown that the output of peptides homologous to the native epitope was 1.7-fold higher for biotinylated antibodies, whereas the binding capacity of the selected phages with mAb 2F5 in ELISA was higher in the case of using non-biotinylated antibodies. It should be noted that the phages exposing peptides, which have 4-5 amino acid sequence similarity with the native epitope, demonstrate the highest binding affinity. The phages that expose peptides with 3 amino acid sequence similarity demonstrate different binding affinity: from the smallest to the largest. Based on the obtained data, it is safe to suggest that the rational biopanning may proceed in accordance with the task.

[Mechanisms of HIV-1 drug resistance to nucleoside and non-nucleoside reverse transcriptase inhibitors]

Global AIDS epidemics caused by human immunodeficiency virus type 1 (HIV-1) has existed for more than 25 years and involved more than 2 million newly infected people annually. The obstacle in combating the global epidemics is a rapid evolution of the virus by the selection of drug resistance mutations. In this review, we have summarized scientific achievements in the field of reverse transcriptase drug resistance to licensed antiviral drugs--nucleoside (NRTI) and non-nucleoside (NNRTI) inhibitors. Principal mechanisms of their antiviral action, major drug resistance mutations, and molecular aspects of classic resistance mechanisms of HIV to NRTIs and NNRTIs are described. Recently discovered role of RNase H activity in development of drug resistance to reverse transcriptase inhibitors is a focus for the detailed discussion. New dual resistance mechanism to NRTIs and NNRTIs associated with the reverse transcriptase mutations in the C-terminal region, which includes RNase H and connection domains, is analyzed. Comprehensive analysis of the factors affecting the HIV drug resistance is important for the understanding molecular mechanisms of resistance for the improvement of drug design and anti-HIV therapy.

[RT-PCR-based methods for identification and typing of infectious hemopoietic necrosis virus in salmons]

A RT-PCR method has been developed to diagnose infectious hemopoietic necrosis virus (IHNV) in salmons. The authors show it possible to use the method for viral shedding in both a cell culture and a clinical sample from infected fishes. Genotyping of IHNV strains originating from North America, Europe, and Russia, by using the restriction fragment length polymerase analysis, has revealed that 10 of them belong to 3 existing genogroups (U, M, and L). Three Russian isolates are assigned into a separate subgroup. Phylogenetic analysis of several isolates has confirmed that viral strains from Katchatka belong to the North American U-genogroup whereas 3 Russian isolates from the continental zone of the country make up a separate subgroup within the same genogroup.

[Humoral immune response of BALB/c mice immunized with chimer HBcAg proteins carrying the epitopes of surface hepatic B virus protein]

Chimeric HBcAg proteins carrying epitopes from surface hepatitis B virus (HBV) protein (regions 137-147 a.o. HBsAg, 27-37 a.a. region preS1 and 131-145 a.a. region preS2) have been early constructed. This paper presents the data of an investigation of a humoral immune response in mice immunized with obtained by chimeric HBcAg proteins. The findings suggest that the chimeric HBcAg proteins carrying the epitopes of surface HBV protein are able to induce an immune response to both inserted epitopes and carrying protein (HBcAg). Immunization with a mixture of chimeric proteins taken in equivalent quantities induces the synthesis of antibodies to hybrid proteins. The use of aluminum hydroxide considerably enhances a humoral immune response during immunization with chimeric bovine proteins.

[Construction of combinatorial immune library of single chain human antibodies to orthopoxviruses and selection from this library antibodies to recombinant protein prA30L of variola virus]

A combinatorial immune library of human single-chain antibody fragments (scFv) was constructed on the base of genes encoding variable domains of heavy and light chains of immunoglobulins cloned from the lymphocytes of four vaccinia virus (VACV) vaccinated donors. The size of the library was 3 x 10(7) independent clones. After the library was enriched with the clones producing scFv against recombinant analogue of variola virus surface protein prA30L, a panel of unique antibodies specific to both prA30L and VACV was selected from the library. A plaque reduction neutralization test was performed for all selected antibodies and two antibodies were shown to be able to neutralize plaque formation of VACV in Vero E6 cells monolayer. Binding specificities of these antibodies were confirmed using ELISA and Western blot analysis. To determine the amino acid sequences of neutralizing antibodies their genes were sequenced.

[Study of a role of artificial mycobacterial particles in the realization of immunological processes in experimental animal tuberculosis]

The protective properties of artificial mycobacterial particles versus BCG vaccine were studied in laboratory animals with experimental tuberculosis. The findings of the decreased rate of a tuberculous process and on the increased mean life span in animals inoculated with M. bovis suggest that immunization of guinea-pigs with mycobacterial particles promotes the enhanced development of antituberculous immunity in the animals. The paper proposes a promising method for designing artificial immunogens, the high-polymer antigenic structures that imitates mycobacterial particles.

[Human recombinant antibodies to variola virus]

Eight specific antibodies to live variola virus (VV), Ind-3a strain, and 7 antibodies to VV, Butler strain, were selected from the synthetic combinatorial phage display library on single-chain (scFv) human antibodies. Indirect solid-phase enzyme immunoassay showed the ability of these antibodies to bind the VV strains Ind-3a, Butler, Brazil-131, Kuw-5, and Congo-2. Moreover, earlier selected human scFv antibodies were also tested in the reaction of binding to the above VV strains. The experiments could reveal the antibodies that bound alastrim strains more effectively that did other VV strains. The nucleotide sequences encoding for the selected scFv antibodies were determined.

[Genetic polymorphism of clinical Mycobacterium tuberculosis strains circulating in the territory of Novosibirsk Region]

Mycobacterium tuberculosis strains isolated from patients treated at TB dispensary branches in different districts of Novosibirsk were studied by genetic analysis. The below molecular methods were used: 1. PCR with random primers; 2. A method based on variable number of tandem repeats in loci; 3. IS6110 inverse PCR. Thirty-five samples of genome DNA of M. tuberculosis isolated were analyzed. Each of the 3 methods detected the main group of isolates, which comprised 61.8% of closely related strains revealed by method 1, 75.8%--by method 2, and 74.3%--by method 3. The remaining clusters were represented by 1 to 4 strains. The data obtained denote a relative homogeneity of M. tuberculosis strains circulating in Novosibirsk Region. No interplay was detected between the clustering of isolates and the presence or absence of mutation in genes conditioning the resistance to antibiotics.

[Different systems of delivery of HIV-1 DNA vaccine encoding the multiepitope CTL-immunogene]

We used, within the case study, virus-like particles (VLP) and attenuated strains of salmonella for the delivery of HIV-1 DNA vaccine encoding the multiepitope CTL-immunogene. The immunogenicity of the thus obtained vaccine constructions was comparatively analyzed. All constructions were shown to be able of inducing, in immunized animals, both the specific T-cell responses and the synthesis of virus-specific antibodies. The lowest level of immune response was registered in animals immunized by "naked" plasmid DNA. The delivery by plasmid DNA involving VLP or the attenuated strain of salmonella enhances the efficiency of the DNA-vaccine presentation to the immune system.

[Anti-measles DNA-immunization in experiment: immunogenicity and safety]

The plasmid DNA pCDNA3.1-H encoding the N-terminal sequence of the measles hemagglutinin (H) protein was constructed. Virus-specific particles (VSP) containing the plasmid DNA pCDNA3.1-H coated by the spermidine-polyglucin complex. The mice were immunized by VSP. ELISA, HAIT and immunoblot showed a shaping specific humoral response. The sera of immunized animals were proven to neutralize the wild strain of the NOV96 measles virus. The formation of the specific cell immunity was confirmed by erythrocyte proliferation assay and ELISpot. PCR was used to detect the presence of the plasmid DNA in different intestines and tissues of animals after a single immunization. It was not detected at any time interval in the brain, liver, thymus and blood. And it was present on days 7 and 14 in the red bone marrow, spleen, muscular tissue, lungs and fatty tissue. On day 21 the plasmid DNA was not detected in any of the investigated organs.

[Presentation of HIV epitopes by HBcAg]

The hepatitis B core antigen (HBcAg) was used to present the HIV epitopes and mimics selected by phage display. The HIV epitopes were inserted into the el loop of HBcAg. The influence of insertions on the ability of chimeric HBcAg to assemble itself was studied. Special soft was made use of to detect the regularities between certain physical-and-chemical properties of amine-acid residua (belonging to an inserted alien peptide) and the presence or loss of the ability of HBcAg to assemble itself. Recommendations are provided of how to overcome difficulties related with the presentation of alien epitopes.

[Human mini-antibodies to orthopoxviruses]

A library of human scFv antibodies displayed on the surface of bacteriophages (MRC, Cambridge, England) was panned against the Elstree strain of vaccinia virus (VACV), which resulted in the phage repertoire enriched with clones positive to the strain. Individual clones from the repertoire were screened for binding, independently, to the vaccinia and ectromelia viruses; phage antibodies to the orthopoxviruses were selected. Ten unique antibodies were identified after their Vh- and Vl-genes were sequenced. All selected antibodies were assayed by ELISA for binding to the vaccinia, cowpox and ectromelia viruses. Furthermore, all selected antibodies were assayed for binding with major alastrim strains of the live variola virus. According to the results, the above phage antibodies recognized genus-specific epitopes, some of which differed in their conformation.

[Application of peptide phage libraries for obtaining peptides specific to mouse lung adenocarcinoma]

Peptides binding, in vivo, with mouse lung adenocarcinoma, were selected from a peptide phage library containing above 100 million of different permutations. The selected phages carrying specific peptides accumulated in the tumor node, after intravenous injections made in A/Sn mice with induced adenocarcinoma, and persisted there even in 24 h after injections; whereas, they were detected in small quantities or not detected at all in other tissues (e.g. lungs and muscles). The selected bacteriophages were shown to accumulate not only in the primary tumor node but also in the lung with multiple metastases. Finally, amino acid sequences of exposed peptides were defined.

[Determination of glycyrrhizic acid binding sites by a phage display method]

Phages that expose peptides specifically interacting with glycyrrhizic acid (GA) were selected from a phage peptide library by affinity selection and ELISA. Amino acid sequence analysis of the selected peptides and human proteins with the SIM program revealed homology to tyrosine protein kinases, serine/threonine protein kinases, tyrosine phosphatases, and some receptors. Analysis of the peptide and virus protein sequences with the BLAST program showed that GA has affinity for various surface proteins of several human viruses such as HIV-1, hepatitis C virus, and herpesviruses.

[Immune response in oral and rectal immunization by the attenuated strain of salmonella carrying the HIV DNA-vaccine]

The recombinant strain of Salmonella typhimurium SL7207/pBMC-env, carrying a plasmid containing the gene of protein HIV-1 gp-160, was obtained under the monitoring by CMV-promoter. The above strain was used in the rectal and oral immunization of BALB/c mice. HIV-specific antibodies were detected in serum after a one-time immunization; such antibodies were able to inhibit the viral replication in vitro. Furthermore, the shaping-up of the specific cytotoxic and of proliferative responses was registered. Finally, the rectal immunization by cells of the Salmonella recombinant strain can be regarded as a promising delivery system of DNA-vaccine (pBMC-env), and it is more effective versus the oral immunization variant.

[Immunogenetic properties of peptides mimicking a human immunodeficiency virus gp41 (HIV-1) epitope recognized by virus-neutralizing antibody 2F5]

Phage display was used to obtain peptides mimicking a HIV-1 gp41 conserved epitope recognized by virus-neutralizing monoclonal antibodies (MCA) 2F5. Rabbits and mice were immunized with the peptides exposed on the surface of filamentous bacteriophages. Antibodies to gp41 were detected in the sera of immunized animals. The virus-neutralizing activity of the sera was examined.

[Artificial anti-HIV immunogens and methods of their delivery]

Elaboration of an anti-HIV vaccine is a highly important task because there is a need to arrest or at least to slow-down the rapid spread of AIDS throughout the world. Regrettably, no attempts to create an effective vaccine resulted in success. Nonetheless, the available data contribute to building up the confidence in that the set purpose can be achieved provided extra resources are found for working out a potential anti-HIV vaccine. The paper contains some results of research conducted by the "Vector" Research Center for Virology and Biotechnology in the field of artificial polyepitope immunogens, which could be potential anti-HIV vaccines, and in the field of creating various system for their delivery. The immunogenic properties of the thus obtained vaccine structures were tested on mice BALB/c. The delivery systems were experimentally demonstrated to ensure the induction of specific antibodies against HIV-1, with such anti-bodies having a virus-neutralizing activity; the above systems also induce the cellular immunity.

[Recombinant antibodies to tick-borne encephalitis virus]

A gene encoding the dimeric form of single-chain antibody fragments (scFv) was designed on the basis of the artificial gene coding monomeric scFv to tick-borne encephalitis glycoprotein E. The sequence encoding histidine oligomer was added to 3'-ends of the genes encoding the monomeric and dimeric forms of scFv antibodies. Escherichia coli strains were constructed for the production of monomeric and dimeric antibodies. These antibodies were purified using Ni-NTA resin. The specificity of the purified monomeric and dimeric antibodies in the binding reaction with tick-borne encephalitis virus was shown by ELISA and Western-blot analysis. The identity of glycoprotein E epitope bound by monomeric and dimeric scFv and parental monoclonal antibodies E6B was confirmed by competitive immunoassay.

[Localization of the HIV-1 gp120 conformational epitope recognized by virus neutralizing monoclonal antibodies 2G12]

A phage peptide library was used to select peptides interacting with virus-neutralizing monoclonal antibodies (mAb) 2G12 which recognize a discontinuous surface epitope of HIV-1 gp120. With the published X-ray data, gp120 regions involved in the antigenic determinant were predicted. Binding with mAb 2G12 was ascribed to Trh-297, Phe-383, Tyr-384, Arg-419, Ile-420, Thr-415, Leu-416, Pro-417, Lys-421, and Trp-112. Though distant in the gp120 sequence, these residues are close in space and form the 2G12 epitope on the gp120 surface.

[Construction and study of antigenic characteristics of recombinant salmonella strain producing TBI protein]

A recombinant strain producing TBI protein (artificial protein containing HIV-1 B and T cell epitopes) was constructed on the base of attenuated Salmonella typhimurium SL7207 strain and BALB/c mice were immunized with this strain in a dose of 10(9) live cells orally or rectally. A single immunization with the recombinant salmonella strain induced humoral and cellular immune response to HIV-1; hence, this strain is a promising candidate for vaccine against HIV.

[Localization of tick-borne encephalitis virus protein E antigenic determinant recognized by antihemagglutinating monoclonal antibodies using a phage-display peptide library]

Bacteriophages bearing peptides reacting with antihemagglutinating monoclonal antibodies (MAb) 10H10 to tick-borne encephalitis (TBE) virus protein E were selected from a phage-display peptide library by affinity selection and enzyme immunoassay. The library contained randomized peptides that are 6 amino acids long, fused with protein pIII and exposed on the surface of the bacteriophage. No significant homology between the sequences of selected peptides and TBE virus protein E was detected. Computer software was created to locate the conformation epitopes on the surface of protein E. Amino acids R73, C74, T76, M77, N103, C105, L107, and S112 were found to form a discontinuous epitope recognized by MAb 10H10. These amino acids are remote in the protein sequence but close in the tertiary structure and form a whole epitope located in the structural domain II of protein E. Presumably the localized amino acids bind to the cellular receptor for TBE virus.

[Comparative study of the effectiveness of HBcAg presentation to the immune system using attenuated Salmonella strains, serovars S.enteritidis and S.typhimurium]

In this work the results of obtaining HBcAg-producing attenuated Salmonella strains, serovars S. enteritidis and S. typhimurium, and their comparative study is presented. As revealed in this study, attenuated S. enteritidis strain E-23 and S. typhimurium strain T-10, producing HBcAg, induce cell-mediated and humoral immune response to HBcAg after injected into anovals. After injection S. typhimurium strain T-10 induces a much higher titer of specific antibodies than S. enteritidis strain E-23. The level of specific antibodies induced by recombinant HBcAg seems to correlate with the capacity of salmonellae for survival inside macroorganisms.

[Structure of over lapping region of ICP18.5 and gB genes of type 1 bovine herpesvirus strain TK-A]

Nucleotide sequence of DNA fragment coding 3'-terminal of ICO 18.5 gene that overlaps the regulatory region and 5'-terminal of open reading frame of gB gene of bovine herpesvirus (BHV-1, subtype 1.3), strain TK-A, was determined. Comparative analysis of the sequence with the corresponding DNA regions of BHV-1, subtype 1.1, equine herpesviruses of the first and fourth types, and porcine pseudorabies virus was performed.

[Experimental evaluation of the biological safety of gene-engineered bacteria using a model strain Bacillus subtilis interferon-producing strain]

The in vitro and in vivo evaluation of the biological and ecological safety of genetically modified bacteria (GMB) was carried out on B. subtilis recombinant strain 2335/105, capable of producing human interferon alpha-2, used as experimental model. As shown in this investigation made with the use of bacteriological analysis and polymerase chain reaction, the oral administration of GMB to calves, chickens and white mice produced no disturbances in the microbial ecology of the gastrointestinal tract of warm-blooded animals and did not lead to the appearance of spontaneous transformants. The present work is the first experimental evaluation of the biological safety of genetically modified microorganisms, used as the component of Subalin, a probiotic preparation intended for use in veterinary practice.

[Construction of peptide mimetics of an epitope of the human immunodeficiency virus (HIV-1) gp41 protein, recognized by virus-neutralizing antibodies 2F5]

A phase peptide library was screened with virus-neutralizing monoclonal antibodies (MCA) 2F5 which recognize a conserved epitope of HIV-1 gp41. Phages that expose peptides specifically binding with MCA 2F5 were selected by ELISA. Amino acid sequence analysis revealed a homology to region 662-671 of HIV-1 HB10 gp160 for most peptides. The major role in recognition was ascribed to Asp-664, Lys-665, and Trp-666. The epitope-mimicking peptides were tested for immunogenicity. Antibodies to gp41 were detected in serum of immunized rabbits.

[Isolation and study of recombinant strains of Salmonella typhimurium SL 7207, producing HBcAG and HBcAG-HBs]

Recombinant strains producing hepatitis B virus (HBcAg) core protein and chimeric core protein exposing on its surface the major immunogenic epitope of HBsAg (HBcAg-HBs) were constructed on the base of attenuated S. typhimurium SL 7202 strain. The resultant Salmonella strains produced proteins which were capable of self-assembly into virus-like particles and showed antigenic properties of both core and surface hepatitis B proteins. A single rectal immunization with recombinant S. typhimurium induced humoral and cellular immune response to HBcAg and HBsAg. Specific anti-HBcAg were detected in animal sera and intestinal tissues, which indicated the formation of specific mucosal immunity.

[Identification and characterization of strains of Bacillus thuringiensis by genomic fingerprinting using biotinylated phage M13 DNA]

Genomic DNA of the entomopathogenic bacterium Bacillus thuringiensis was analyzed by the genomic fingerprinting technique. The biotin-labeled single-stranded DNA of the phage M13 was used as a marker of hypervariable sequences. A procedure for analyzing the differentiation among various Bacillus thuringiensis strains was developed. Characteristic patterns of fingerprints were obtained for several strains, the main representatives of subspecies that are most frequently used in the manufacture of bacterial insecticides, such as subsp. thuringiensis, subsp. kurstaki, and subsp. galleriae. Because no essential differences were revealed in band patterns upon comparing fingerprints of crystal-producing bacterial strains with those of acrystallic mutants, it was assumed that the loss of crystal-producing ability in the insect pathogen Bacillus thuringiensis is not connected with significant rearrangement of its genome.

[Detection of the hog cholera virus using the polymerase chain reaction]

A rapid and highly sensitive method for detecting hog cholera virus (HCV) based on a reverse transcription of the polymerase chain reaction (RT-PCR) is developed. Primers complementary to the most homologous sites of virus genome in an area coding the precursor for glycoproteins gp44/gp48 are selected. Detection of the virus in pathological material by the RT-PCR showed that use of these primers in amplification allows detection of different HCV strains.

[Preparation of single-chained antibodies to surface glycoprotein E from tick-borne encephalitis virus]

A single-stranded antibody gene scFv was designed on the base of cDNA fragments of genes coding for variable domains of heavy and light chains of MAb E6B to tick-borne encephalitis glycoprotein E. High production of stable soluble scFv was reproduced in Escherichia coli cells. Recombinant antibodies bound to antiidiotypical antibodies to initial MAb E6B and to recombinant virus protein E. Competitive analysis showed that single-stranded antibodies inhibited reaction between MAb E6B and protein E. These results confirm the formation of scFv with the original antigen-binding specificity towards tick-borne encephalitis virus glycoprotein E.

[The development and certification of the Hepabest anti-HBc IgG test system for detecting antibodies to the core antigen of the hepatitis B virus]

The comparison of the newly developed "HepaBest anti-HBc IgG" assay system for the detection of hepatitis B virus (HBV) core antigen with the reference system "ImmunoComb HBc IgG" (Orgenics, France-Israel) and its approbation on 91 serum samples from patients in the Infectious Clinical Hospital were carried out. The coincidence rate of the results obtained with the use of the two assay systems was 87.9%. The system "HepaBest anti-HBc IgG" permitted the detection of patients whose sera contained no other HBV markers, except anti-HBc IgG. This assay system may be recommended for use in clinical and epidemiological investigations for ascertaining the diagnosis.

[Chimeric hepatitis B core antigen particles as a presentation system of foreign protein epitopes]

The paper presents data available in the literature and the author's own experimental findings as to the construction of chimeric hepatitis B core antigen (HBcAg) particles. The problems associated with the design of hybrid HBcAg particles and the ways of solving arising problems are considered. Data from studies of the antigen and immunogenic properties of hybrid HBcAg particles.

[Use of a phage peptide library in mapping the group-specific hemagglutinating domain of alpha-virus glycoprotein E2]

Phage display peptide library f88-4/15 (G. P. Smith, USA) was used for mapping the hemagglutination activity domain of glycoprotein E2 of alphaviruses. Using affinity selection and ELISA, we selected the clones binding monoclonal antibody 4H5 to Venezuelan equine encephalomyelitis virus and inhibiting alphavirus hemagglutinating activity. Analysis of the similarity between the peptides amino acid sequences with the alphavirus glycoprotein E2 sequences revealed a structural motive of 4 amino acid residues (HTSR) which was identified in the 85-88 region. Bacteriophages F36 and F19 contained motives corresponding to 102-SXXM-105 and 109-AXXP-112 regions in alphavirus proteins E2. These data permit us to propose that the detected regions are fragments of a group-specific alphavirus hemagglutination domain.

[Synthesis, cloning, and expression in Escherichia coli cells of human alpha1-antitrypsin cDNA]

cDNA coding for the full-length human alpha 1-antitrypsin (AAT) and its leader sequence has been cloned and sequenced. DNA sequences encoding the deletion variants and a full-length copy of AAT were cloned and expressed under trp-promoter control. It has been shown that guanine replacing right upstream and downstream the ATG of deletion variant increases the expression to ten-fold. The synthesis of deletion AAT in E. coli was evaluated immunologically and the level of the synthesis was shown to be 4-5% of total cellular protein.

[Identification and classification of strains of microorganisms using genomic fingerprinting with biotinylated phage M13 DNA]

To analyze DNA polymorphisms of various bacterial strains, a nonradioactive variant of the genomic fingerprinting method was developed. The method was based on the application of biotin-labeled single-stranded phage M13 DNA as a probe. Characteristic patterns of fingerprints obtained by MvaI, HaeIII, and HinfI restriction enzymes are presented for several species of bacilli and other bacteria. The advantages of this method in microbiology for the identification and characterization of different microbial strains are shown.

[Ability of a recombinant protein containing fragment 114-122 of myelin basic protein, to cause allergic encephalomyelitis in guinea pigs]

Four genetic constructions have been designed, capable of producing in E. coli the hybrid beta-galactosidases containing the encephalitogenic determinant 114-122 of myelin basic protein. The ability of chromatography-purified proteins to cause allergic encephalomyelitis in guinea pigs has been investigated. Only one out of four proteins carrying at least one complete replica of encephalitogenic determinant did induce allergic encephalomyelitis in animals. Effects of the structural context of the encephalitogenic determinant on its functional activity are discussed.

[Detection of the spring viremia of carp virus by hybridization with nonradioactive DNA probes]

In order to detect spring viraemia of carp virus, DNA probes have been constructed using reverse transcription-PCR amplification technique and cDNA cloning in plasmid and phage vectors. The sensitivity and specificity of viral RNA detection was assessed using nonradioactive probes in infected FHM cell culture and in tissues from dead fish. Viral RNA was more frequently detected in the brain and gill than in the abdominal organs.

[Detection of bovine infectious rhinotracheitis virus by hybridization using nonradioactive DNA-probes]

Biotin-labeled DNA probes for infectious bovine rhinotracheitis virus also known as bovine herpesvirus-1 (BHV-1) have been developed. The procedure is based on dot-blot hybridization using biotin-labeled bacteriophage M13 and plasmid probes containing cloned PstI and EcoRI-PstI restriction fragments of viral genome. The probes obtained were used to detect viral nucleic acids in specimens of bovine spermatic fluid or nasal swabs of calves. The method is simple and rapid, taking less than 24 h, and is highly specific and sensitive, this recommending it for practical veterinary.