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O V Rokhlin

Publications and source records attributed to O V Rokhlin.

13 recordsLinked to original sources
PubMed1987

Monoclonal antibodies to dog heart sarcoplasmic reticulum. Antibodies that inhibit Ca2+-pump systems of cardiac and skeletal muscles.

Purified sarcoplasmic reticulum (SR) vesicles from dog heart were used as an antigen to produce monoclonal antibodies (mAbs) to the Ca2+-ATPase. Nine of twelve clones of hybridoma cells produce mAbs which cross-react with seven SR preparation isolated from cardiac and skeletal muscles of various species. Three mAbs of IgM type interact with the 45-kDa tryptic fragment of rabbit skeletal muscle Ca2+-ATPase and markedly inhibit Ca2+ uptake (by 95%) and ATPase activity (by 80%) and decrease (by 30-50%) the steady-state level of the Ca2+-ATPase phosphoenzyme. The ATPase activity could be completely blocked by one of these mAbs if the incubation medium was supplemented with 2 microM orthovanadate. On the other hand, when SR vesicles were treated with increasing concentrations of a nonionic detergent C12E8, the inhibiting effect of mAb 4B4 is diminished. It is concluded that the mAbs inhibit the Ca2+-ATPase only if the enzyme exists in an oligomeric form. The inhibition of the SR activities is due to an effect of the mAbs on the whole active center of the enzyme, rather than on a single partial reaction.

Animals↗
PubMed1987

Monoclonal antibodies to dog heart sarcoplasmic reticulum. Application of the mAbs for studies of the structure and function of Ca2+-pumps.

One of monoclonal antibodies (mAbs) raised against purified dog heart sarcoplasmic reticulum (SR) efficiently decreases Ca2+-pump and Ca2+-ATPase activities of various SR preparations. The ATPase activity that is insensitive to the mAb (10-20% of the initial value) is present both in light and heavy fractions of rabbit skeletal muscle SR. The residual activity is completely blocked by 2 microM vanadate. The inhibition of the ATPase by the mAb is prevented in the presence of a nonionic detergent C12E8. It is concluded that the inhibiting effect of the mAb takes place when the Ca2+-ATPase exists in an oligomeric form. Another mAb does not affect SR functions and is specific only for Ca2+-ATPase from cardiac and slow muscle cells. Decrease in the Ca2+-pump activity of SR fractions from ischemic myocardium is accompanied by a diminished binding of both mAbs with the antigen. The mAbs described could be employed for differentiating endoplasmic reticulum and plasma-lemmal calcium pump systems, visualization of SR in the cells and estimating its amount in membrane preparations and tissue homogenates.

Animals↗
PubMed1985

Monoclonal antibodies against common and Igk-1a allotypic determinants of rat immunoglobulin kappa chain constant domain.

SJL/J mice were immunized with polyclonal rat Ig light chains of two allotypes and immune spleen cells were fused with P3-Ag8.653 myeloma cells. 17 cell populations producing antirat Ig AB were cloned. Four clones, 1G9, L3E8, L2B2 and L2C5 have been characterized in detail. All MABs are of the IgG1, kappa isotype. Using monoclonal rat kappa chains it was demonstrated that all the AB react with rat Ig kappa chains. Further localization of antigenic determinants was performed using isolated L chain C domain. It was shown that all MABs are directed against C domain epitopes. L2C5 MAB binds selectively to August rat L chains, thus showing specificity for Igk-1a determinants. The remaining three clones bind equally well to L chains of different allotypes, but 1G9 clone binds preferentially to isolated L chains as compared to intact IgG molecules.

Animals↗
PubMed1979

Immunochemical studies of beef pancreas tryptophanyl-tRNA synthetase and its fragments. Determination of the number of antigenic determinants and a comparison with tryptophanyl- tRNA synthetases from other sources and with reverse transcriptase from avian myeloblastosis virus.

The immunoglobulin G (IgG) fraction of the antiserum from rabbits immunized with homogeneous beef pancreas tryptophanyl-tRNA synthetase inhibits the enzyme activity in the reactions of both tRNATrp aminoacylation and tryptophan activation. Fab fragments of IgG act in a similar way. Common antigenic determinants have been detected in tryptophanyl-tRNA synthetases from beef, pig, chicken and rat livers using pure antibodies against beef pancreas tryptophanyl-tRNA synthetase. This observation indicates the evolutional stability of certain structural features of tryptophanyl-tRNA synthetases. The interaction of antibodies with the fragments of beef tryptophanyl-tRNA synthetase produced by endogenous and tryptic proteolysis of the enzyme has been studied. On third of the antiserum antibodies interacting with the C-terminal fragment of the enzyme (Mr approximately equal to 40000) inhibits its activity whereas the antibodies to the N-terminal fragment (Mr approximately equal to 20000) have no effect on the enzyme activity. The immunochemical identity of the two synthetase fragments differing in their enzymatic activity supports the assumption that the loss of enzymatic activity of the tryptic fragment is caused by lack of a small peptide which is retained in case of endogenous proteolysis; probably the amino acid residues of this peptide participate in formation of active centre of tryptophanyl-tRNA synthetase. A radioimmunochemical method is described for determining the number of antigenic determinants. One molecule of tryptophanyl-tRNA synthetase was found to bind 9 (+/- 1) molecules of Fab fragments. Antibodies against tryptophanyl-tRNA snythetase from beef pancreas do not inhibit noticeably the activity of reverse transcriptase from avian myeloblastosis virus. No antigenic determinants in common have been detected in reverse transcriptase and tryptophanyl-tRNA synthetase by radioimmunochemical assays.

Amino Acyl-tRNA Synthetases↗
PubMed1978

The number of antibody-producing clones as revealed by the distribution of allelic variants of immunoglobulin light chains.

A new method of evaluation of the number of clonal precursors of antibody-producing cells based on the phenomenon of allelic exclusion is proposed. The distribution of the allotypes of specific antibodies in the population of heterozygous F1 hybrids depends on the number of clonal precursor cells. The smaller the number of precursors, the larger the variance of the distribution. The frequency of clones producing antibodies to the azobenzoate hapten (approximately 10(-8) after first and approximately 10(-9) after second and third immunizations) in (MSU X August)F1 rats calculated in the present work is in reasonable agreement with the data obtained (for other haptens) by limiting dilution cloning assays. The difference in the numbers of anti-hapten and anti-carrier clones is discussed. The numbers of IgM and IgG-synthesizing clones are calculated from the distributions of the allelic variants of corresponding rat antibodies to lactoside. The data suggest the existence of distinct IgG precursors which contradicts the hypothesis of IgM-IgG switch within the clones only.

Alleles↗
PubMedDate not supplied

[Study of the antigenic structure of human immunoglobulin lambda-chain using monoclonal antibodies].

Nine monoclonals against human Ig lambda chains were produced, 4 antibodies react with C-domain, 5--with V-domain of the lambda chain. Anti-C lambda domain antibodies recognize not less than 3 epitopes and one of them is expressed only on the isolated chain. Anti-V lambda antibodies bind both isolated lambda chain and intact IgG, IgM, IgA. Four epitopes are expressed by few lambda Bence Jones proteins of the III subgroup, the immunogen possessing the same isotype. The 4 mentioned epitopes represent private idiotypic determinants. The epitope 3E10 is characteristic of 50% Bence Jones proteins of the II and III V lambda-subgroups thus representing a common idiotypic determinant. Using anti-V lambda antibodies germ line variability of V lambda III proteins was analysed and the similarity of antigenic structure of normal and myeloma human Ig lambda chains was demonstrated.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Antigenic determinants of the constant region of human immunoglobin kappa-chain detected by monoclonal antibodies].

Ten different monoclonal antibody (monAB) preparations reacting with human IgL chains of the kappa type have been obtained. Nine of the monAB interacted with the kappa-chain C domain, whereas only one monAB reacted with the V domain. It has been determined that monAB against the C domain react with three different epitopes. One epitope is expressed on intact Ig molecules as well as on isolated kappa-chains, whereas the other two epitopes are found only on isolated kappa-chains. The expression of these epitopes in 40 different myeloma kappa-chain preparations belonging to four various subgroups was studied. The level of this C domain epitope expression has been shown to depend on the variable subgroups of kappa-chains indicating a close association between V and C domains. This association leads to the alteration of antigenic activity of some C domain epitopes. The alterations are thought to be local because, as a rule, they involve only one of the three epitopes.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Immunochemical comparison of tryptophanyl-tRNA-synthetases].

A fraction of immunoglobulins was isolated from the sera of rabbit immunised by a homogeneous beef pancreas tryptophanyl-tRNA-synthetase (TRSase). The IgG fraction was shown to inhibit the enzymatic activity during aminoacylation of yeast tRNATrp and tryptophan activation. By using the radioimmunoadsorption technique, the interaction of IgG was tested with TRSaes from beef pancreas and identical enzymes from other sources (contained in the total preparation). Beef liver TRSase efficiently inhibited the radioimmunoadsorption reaction of beef pancrease 125J-TRSase that suggests a strong similarity or even identity of the enzymes. When the purified antibodies to beef pancreas TRSase were isolated common antigen determinants were revealed for TRSase from beef pancreas, liver of chick, pig and rat. Enzymatic activity of TRSase from liver of beef, pig and chick was shown to be inhibited by antibodies to beef pancreas. TRSase whereas the enzymes from rat liver and yeast did not change their activity in the presence of these antibodies. Therefore, for several TRAases common antigen determinants have been revealed that suggest the presence of common structural elements in these enzymes; antibody binding inhibits the activity of some TRSases and does not affect that of others.

Amino Acyl-tRNA Synthetases↗
PubMedDate not supplied

[Switch in the synthesis of IgM--IgG antibodies. I. Ratio of allelic variants of light rat immunoglobulin chains in antilactoside antibodies of different classes].

Ratio of allelic variants was studied of the rat immunoglobulin light chains in IgM and IgG fractions of anti-lactoside antibodies isolated from the sera of immune heterozygous rats (WAGXMSU)F1 and (AugustXMSU)F1. For MSU rat strain, RL1 allelic variant of light chains is typical whereas WAG and August strains possess the RL2 variant. Anti-lactoside antibodies isolated from sera of F1 rats were separated into high affinity and low affinity fractions. Thereafter each fraction was divided into IgG and IgM classes and each preparation was tested for the content of the molecules of the antibodies with light chains of RL1 and RL2 type. It has been shown that the ratio of allelic variants coincides in IgM and IgG antibody fractions. It follows from this fact that the IgG switch of antibody synthesis may process in the same cell during development of the given population of antibody-producing cells.

Alleles↗
PubMedDate not supplied

[Immunochemical properties of tryptophanyl-tRNA synthetase and its fragments].

The interaction between beef pancreas tryptophanyl-tRNA synthetase and its fragments produced after limited proteolysis, with IgG fraction of antiserum and with Fab fragment of IgG has been studied. Both the intact antibodies and Fab fragments inhibit the enzyme activity in tRNA aminoacylation and tryptophan dependent ATP-32P pyrophosphate exchange reactions. However, the enzyme inhibited by antibodies is still able to form a complex with tryptophanyl-tRNA. The enzymatically active fragment obtained after endogenous proteolysis interacts only with 1/3 of the antibodies against native enzyme. The fragment produced by trypsinolysis possess similar immunochemical properties. This fragment has almost the same molecular weight but is enzymatically inactive. Pure antibodies against tryptic fragment isolated by means of specific immunoabsorbent inhibit the enzymatic activity. The antibodies which do not interact with this fragment (2/3 of the total amount of antibodies) have no influence on the enzymatic activity. The immunochemical identity of the two synthetase fragments differing in their enzymatic activity supports the assumption that the loss of enzymatic activity of the tryptis fragment is caused by lack of a small peptide which is retained in case of endogenous proteolysis. Probably the amino acid residues of this peptide participate in formation of the active centre of tryptophanyl-tRNA synthetase. A new procedure for determination of the number of antigenic determinants in proteins is developed. It is shown by this method that beef pancreas tryptophanyl-tRNA synthetase contains 9 +/- 1 antigenic determinants.

Amino Acyl-tRNA Synthetases↗
PubMedDate not supplied

[Antigenic markers of variable region of mouse myeloma MOPC 21 light chain].

Monospecific antibodies against V-region of the L-chain of the mouse myeloma protein MOPC21 (VK 15 group) were obtained and used for preparation of antibody-immunoadsorbents. By means of the immunoadsorbents the content of normal immunoglobulins with antigenic markers of VK 15 group in the serum of mouse strains BALB/c, CBA and C57BL/6 was determined. The least quantity of the proteins determined by this method was estimated to be 1.4%. If each of K-chains of the variable groups is represented equally in the population of normal immunoglobulins, the number of VK groups and respectively germ-line VK genes should be not less than 70.

Animals↗
PubMedDate not supplied

[Participation of rat immunoglobulin light chains of the kappa and lambda type in formation of antibodies to the polysaccharide of group A streptococcus].

The role of light kappa and lambda chains and also allelic variants of kappa chains of rat immunoglobins in the formation of antibodies to beta-N-acetyl-glucosamine polysaccharides of streptococcus group A of inbred rat strains MSU, WAG, August and hybrids of the first generation (MUS X WAG)F1 and (MSU X August)F1 was studied. From individual sera of immune rats fractions of specific antibodies to beta-N-acetyl-glucosamine were isolated. These antibodies differ in their affinity to antigenes. The retio of molecules with kappa and lambda light chain types was determined for the fraction of specific antibodies. The ratio of molecules kappa and lambda depends on the affinity of antibodies to beta-N-acetyl-glucosamine and on the genotype of the animals studied. Data obtained allow to conclude that differences in the functional activity of lambda chains between strains WAG and August, on one hand, and strain MSU, on the other, do exist. Functional differences releaved between these rat strains were confirmed by analyzing corresponding antibody fractions to beta-N-acetylglucosamine in F1 hybrids. Differences between allelic variants of kappa chains in the formation of antibodies to beta-N-acetylglucosamine of polysaccharides were not found.

Acetylglucosamine↗