[Analysis of the frequency of allelic exclusion of immunoglobulin light chain genes and molecular characteristics of immunoglobulins secreted by hybridomas with expression of both allelic genes]. / Analiz chastoty allel'nogo iskliucheniia genov legkikh tsepei immunoglobulinov i molekuliarnaia kharakteristika immunoglobulinov, sekretiruemykh gibridomami s ékspressiei oboikh allel'nykh genov.

The investigation of 750 B-lymphocyte hybridoma clones obtained by fusion of mouse myeloma and newborn heterozygous Igk-la/Igk-1b rat splenocytes has revealed that 9,8% of Ig kappa-chain genes are rearranged productively. Seventeen hybridomas secrete kappa-chains of both allelic variants. The analysis of IgM molecules of nine such clones demonstrated that in six cases only one L-chain allotype is present in IgM. Thus for the first time the high frequency of selective association of H and L chains was shown. Evidently this selectively may function as one of the allelic exclusion mechanisms at the Ig assembly stage.

Antigenic markers of V domain of mouse MOPC 21 IgG1 L chain. The conformational basis of VL domain markers and content of MOPC 21 VL-like immunoglobulins in sera of inbred mouse strains.

Antisera were raised in rabbits against L chains, isolated from mouse myeloma protein MOPC21 (gamma 1, chi V chi 15 group). Specific antibodies for the V and C domain of MOPC21 L chain were obtained by cross-immunoadsorption of the antisera. The pure anti-V and anti-C antibodies were fixed on diazocellulose and used as immunosorbents. The inhibitory capacity of L chin-monomers and dimers isolated from the L chain preparation was compared to that of intact IgG1 using binding inhibition of 125I-labeled IgG1 on the antibody-containing immunosorbents. It was established that changes of IgG1 quaternary structure influences the conformational state of the L chain V domain only. The inhibitory capacity of the V domain is 1000-fold lower in L monomers, if compared with native IgG1, and only 10-fold lower than in L dimers. The inhibiting capacity of the C domain, however, does not differ in L monomers and intact IgG1. Thus the conformational rigidity of the C domain co-exists with conformational flexibility of the V domain on the same polypeptide chain. We tried to estimate the content of MOPC21 V1-like normal IgG in mouse serum of 6 inbred strains using antibodies against the V1 domain. Data obtained by inhibition of radioimmunoadsorption, indicate that in C57BL/6 mice 0.08% of normal serum Ig carries a V1 region which is idiotypically related to the V1 of MOPC21. In serum Ig of BALB/c mice the percentage is 0.16.

[Immunochemical study of the conformational properties of the variable and constant domains of the light chain of mouse MOPC myeloma immunoglobulin]. / Immunokhimicheskoe issledovanie konformatsionnykh svoistv variabel'nogo i postoiannogo domenov legkoi tsepi mielomongo immunoglobulina myshi MOPC 21.

The antigenic activity of variable (V) and constant (C) domains of mouse myeloma MOPC 21 light (L) chain has been used as a probe of their conformational state. The conformational properties of L-monomers, L-dimers and native IgG1 MOPC 21 protein were investigated by the reaction of inhibition of radioimmunoadsorbtion. Antibodies against the C-domain and different regions of V-domain were used in these experiments. It was shown that V-domain of L-monomers has sharp local conformational disruptions as compared with the native protein, while the conformational state of C-domain remains stable in monomers, dimers and native protein. It was found that the coinformational flexibility of different parts of V-domain of L-monomers is not equal. The antigenic activity of V-domain is partly restored in L-dimers, reaching the conformational state close to that of v-domain in the native protein. The possible interrelation between the conformational properties of V-domains and their functional activity is discussed.

[Antigenic markers of variable region of mouse myeloma MOPC 21 light chain]. / Antigennye markery variabel'noi oblasti legkoi tsepi mielomnogo immunoglobulina myshi MOPC 21.

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.