Identification of monoclonal antibody At5 as a new member of HNK-1 antibody family: the reactivity with myelin-associated glycoprotein and with two brain-specific proteoglycans, phosphacan and neurocan.

Monoclonal antibody At5 was primarily developed against chordin, a notochord-specific antigen of Acipenseridae (sturgeon fishes). In higher vertebrates the antibody reacted mainly with neural tissue antigens. In this study we have shown that the specificity of monoclonal antibody At5 is similar to that of antibodies of HNK-1 family which react with two glycolipids and with several high molecular weight glycoconjugates of neural tissue. We have demonstrated by protein sequencing and immunoblotting that one of At5 target antigens of human brain is dMAG, a derivative of myelin-associated glycoprotein. In the preparations of At5 antigens proteoglycans phosphacan and neurocan were identified by immunoblotting with specific monoclonal antibodies 6B4 and 1G2, respectively. The distribution of At5 and 6B4 immunoreactivity was studied on sections of mixed oligoastrocytoma. Oligodendroglioma area of this tumor was intensely stained with both antibodies, whereas astrocytoma area did not exhibit any At5 or 6B4 immunoreactivity.

[Ontogenetic expression of neurochordin D--a specific glycoprotein from human brain]. / Ontogeneticheskaia ékspressiia neirokhordina D--spetsificheskogo glikoproteina mozga cheloveka.

Neurochordins constitute a family of several immunologically interrelated nervous tissue glycoproteins occurring in the soluble protein fraction of the brain of all vertebrate species including human. The only exception is neurochordin D which, as it has been shown in the present study, is present in human brain but not in the brains of rats and chickens. Human neurochordin D is first detected in the brain at the age of 18 months and further persists through life. A highly purified neurochordin D preparation has been obtained by immunoaffinity chromatography combined with biochemical protein fractionation. Quantitative carbohydrate analysis revealed the presence of Gal, Man, GlcNAc, Fuc and GalNAc in the neurochordin D preparation. The sensitivity of neurochordin D to neuraminidase suggests the presence of sialic acids.

[Insertion mutants of the vaccinia virus. The effect of inactivating E7R and D8L genes on the biological properties of the virus]. / Insertsionnye mutanty virusa ospovaktsiny. Vliianie inaktivatsii genov E7R i D8L na biologicheskie svoistva virusa.

The integrative plasmids with the expressive marker gene for beta-galactosidase were constructed for insertional inactivation of nonessential genes E7R and D8L of vaccinia virus located in the central region of the viral genome. Inactivation of the D8L gene in the strains WR and LIVP results in smaller viral plaques in the culture of chicken embryo cells, decreases the viral ability to propagate in mouse brain and has no effect on the size and character of damage in intracutaneous infection of rabbits. Inactivation of E7R gene did not affect the known biological properties of the virus. The existence of the nonessential genes in the central region of the viral genome, inactivation of which does not result in viral attenuation, can be used for increase of antigenic activity of the live attenuated vaccines.

[Vaccinia and ectromelia recombinant viruses, causing an infection, characteristic for ectromelia, in mice]. / Rekombinanty virusov ospovaktsiny i éktromelii, vyzyvaiushchie kharakternye dlia virusa éktromelii porazheniia u myshei.

Ten recombinants between the viruses of vaccinia and ectromelia were isolated that cause the ectromelia virus specific lesions in mice. The structure of recombinant viral genomes, the efficiency of viral propagation in mice, the nature of lesions induced by viruses have been studied. Eight of obtained recombinants have a DNA insertion originating from the right end of ectromelia viral genome, nine recombinants have an insertion originating from the left end, seven recombinants possess both insertions. The latter recombinants have more pronounced pathogenicity for mice. Both revealed regions are supposed to define the specific pathogenicity of ectromelia virus for mice.

Biologic properties and genome structure of the recombinants between ectromelia and rabbitpox viruses.

Administration of rabbitpox virus (RPV) DNA, cleaved into 2 fragments by SmaI restrictase, into ectromelia virus (EMV)-infected chick fibroblast cells yielded recombinants whose properties were characteristic of both parents. Some recombinants capable of producing RPV-type lesions upon intracutaneous (i.c.) infection of rabbits could also produce EMV-specific lesions upon footpad inoculation of mice. The analysis of some recombinants as well as vaccinia virus strains has shown that the ability of the virus to reproduce when injected into the mouse footpad is a necessary, but not a sufficient condition for production of EMV-type lesions. According to restrictase analysis of recombinant DNA, the genome of recombinants mainly consists of RPV DNA sequences with insertions of small EMV DNA fragments.

[Physical mapping of DNA-temperature-sensitive mutations of vaccinia virus]. / Fizicheskoe kartirovanie DNK-temperaturochuvstvitel'nykh mutatsii virusa ospovaktsiny.

Four DNA-temperature-sensitive (ts) mutations were mapped in the genome of vaccinia virus (VV). Physical mapping of these mutations was performed by restriction analysis of the genomes of recombinants between VV DNA- ts mutants and ectromelia virus as well as by the marker rescue with cloned restriction fragments of VV DNA. One of the mutations was mapped on the HindIII-E-fragment. Biochemical studies of this mutant indicate that the mutation is not in the DNA polymerase gene which is located on the same fragment. The other three mutations were mapped in a 10 kilobase region in the middle of the HindIII-D-fragment. As shown previously, these mutations inactivate different genes, and the products of these genes participate directly in the DNA synthesis. Thus, at least three proteins involved in the VV DNA synthesis are encoded by neighboring genes in the central part of the viral genome.

Processing of influenza HA protein in MDCK cells: components with different mobilities in polyacrylamide gel electrophoresis and their precursor-product relationships.

In influenza virus-infected MDCK cells labelled with 14C-chlorella hydrolysate or 35S-methionine a virus-specific protein component is revealed migrating slightly faster than HA protein in polyacrylamide gel electrophoresis. Under chase conditions the component disappears either completely or partially, with a concomitant intensification of the HA band. The rate and extent of this transition are strain-dependent. Both the HA band and the faster moving component are not revealed if the cells are labelled in the presence of 20 mM of D-glucosamine. In primary cell cultures of chick embryos a single HA band with a mobility similar to that of the faster moving component in MDCK cells has been observed. It is suggested that the transition of the label from the faster moving component to the HA band reflects the final step of HA processing specific for MDCK cells.

Stability in Newcastle disease virus-infected cells of HN protein which lost its functional activity under conditions of protein synthesis inhibition by cycloheximide.

Chick embryo cell cultures were infected with Newcastle disease virus (strains Italia, Beaudette and B1), labelled with 14C-amino acids from 5 to 6 hr post infection (p.i.), incubated in chase conditions from 6 to 10 hr p.i. in the presence or absence of cycloheximide (100 microgram/ml) and analyzed by slab polyacrylamide gel electrophoresis and autoradiography. In chase experiments the HN protein was stable in all three strains. The haemagglutinating activity of cell homogenates was greatly reduced after the addition of cycloheximide in tests with Beaudette and B1 strains; treatment of the homogenates with neuraminidase from Vibrio cholerae did not influence this effect.

[Differences in the polypeptide composition of virulent and avirulent strains of Newcastle disease virus in reproduction in chick embryo fibroblast culture]. / Razlichiia v polipeptidnom sostave virulentnykh i avirulentnykh shtammov virusa bolezni N'iukasla pri reproduktsii v kul'ture fibroblastov kuringo embriona.

The loss of the capacity for secondary infection of the cells in reproduction of avirulent Newcastle disease virus strains in chick embryo fibroblast cultures was found. This loss was shown to be associated with changes in the polypeptide composition of the virions. In virions of the avirulent Queensland strain incapable of infection CEF cultures an additional polypeptide was found with molecular mass of 67,000 daltons which was lacking in virions of the virulent Beaudette strain and corresponded to F0 protein of paramyxoviruses.