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Biomedical subjects

A Nisonoff

Publications and source records attributed to A Nisonoff.

At least 145 records · Page 8Linked to original sources
PubMed1972

Quantitative investigations of idiotypic antibodies. VI. Idiotypic specificity as a potential genetic marker for the variable regions of mouse immunoglobulin polypeptide chains.

Antisera were prepared in rabbits against anti-p-azobenzoate antibodies of an A/J and a BALB/c mouse and anti-p-azophenylarsonate antibodies of an A/J mouse. After appropriate absorption the antisera reacted with the anti-hapten antibody of the donor mouse but, by sensitive quantitative tests, not at all with other components of the hyperimmune serum or with preimmune serum of the donor mouse. The absorbed antiserum therefore appeared to be specific for idiotypic determinants. Nearly all idiotypic specificities identified in the serum of the donor were also present in the serum of other mice of the same strain, immunized against the same hapten group, but not in mice immunized with a different hapten. In each case the antibodies of the donor mouse reacted most effectively on a weight basis with antiidiotypic antiserum. Cross-reactions were observed among different strains of mice but homologous anti-bodies reacted most effectively with antiidiotypic antisera. C57/BL and DBA antisera contained very low concentrations of specificities present in the A/J and BALB/c antibody populations; antibodies of A/J and BALB/c antisera are more closely related to one another. The results indicate that idiotypic specificity may provide a genetic marker for the variable regions of immunoglobulin polypeptide chains.

Animals↗
PubMed1971

Significance of bivalence of antibody in viral neutralization.

The role of bivalence of antibody in its capacity to neutralize virus was studied with rabbit antibodies to the bacteriophage, phiX174. Univalent Fab or Fab' fragments of IgG isolated from antiviral antisera obtained early in the immunization schedule had virtually no activity compared to that of the intact IgG. When the antibodies were isolated from antisera of the same rabbits several months later, the univalent fragments and IgG were essentially equal in activity. The results are interpreted on the basis that an IgG molecule, because of its bivalence, has a higher effective combining affinity (avidity) than a univalent fragment. After prolonged immunization, however, the affinity of univalent antibody becomes sufficiently high that it exceeds a threshold value, above which further increase in affinity, through bivalence, is no longer significant. The results could explain the variability in relative effectiveness of univalent antibodies observed in previous studies. These data, and the fact that F(ab')(2) fragments from either "early" or "late" antisera were as effective as IgG, indicate that fragment Fc is not a significant factor in neutralization. No differences in dissociation from the virus of univalent antibody from early and late antisera could be demonstrated by dilution at temperatures up to 47 degrees C. The attachment at sites of neutralization on the virus appears to be functionally almost irreversible in this system.

Animals↗
PubMed1971

Quantitative investigations of idiotypic antibodies. V. Factors affecting the persistence and replacement of clones of antibody-producing cells.

The effect of challenge by antigen on persistence of clones of antibody-producing cells and on the induction of new clones was investigated through quantitative measurements of idiotypic specificities. In each of nine rabbits idiotypic specificities present in the earliest bleedings were completely replaced after a few months; subsequent changes occurred much more slowly. On a quantitative basis the population of molecules used as immunogen always reacted most effectively with the homologous anti-idiotypic antiserum. Little effect of increased antigen dose on the rate of change of idiotype was observed. Even large amounts of antigen administered every 2 wk caused only gradual changes in idiotypic specificities. This was attributed either to more effective capture of antigen by memory cells, as compared to precursor cells, or to the induction of tolerance in those clones that were not expressed. In two of three rabbits on a monthly injection schedule, the idiotypic specificities identified underwent very slow changes over a period as long as 17 months. Changes occurred more rapidly when antigen was administered every 2 wk. In each of four rabbits investigated, all idiotypic specificities identified before a 5 month rest period were still present afterwards, indicating the survival of essentially all clones of antibody-producing cells during that interval. Quantitative inhibition data indicated that some new clones of cells were initiated.

Animals↗
PubMed1971

Immunofluorescent evidence for cellular control of synthesis of variable regions of light and heavy chains of immunoglobulins G and M by the same gene.

Two distinct paraproteins (IgG(2)-K and IgM-K) from one patient shared identical light chains and significant portions of the variable regions of the heavy chains. Idiotypic determinants on the IgG and IgM molecules were shared. Earlier studies, using class-specific antisera, showed that these paraproteins were produced by two different populations of cells. The present study, using rhodamine and fluorescein conjugates of the anti-idiotype antisera, demonstrates that all plasma cells that contain immunoglobulin, whether IgG or IgM, stained with anti-idiotype antisera; this occurred irrespective of whether the antisera were made originally against the patient's IgG or IgM. This, plus previous data, indicates that both populations of cells share genetic information for the constant and variable regions of light chains and significant portions of the heavy-chain genes. These, and other cited data, strongly suggest the occurrence of a switch-over from IgM to IgG synthesis in the same cell during the course of the normal immune response.

Animals↗
PubMed1971

Reaction of anti-idiotypic antibody with the hapten-binding site of a myeloma protein.

Rabbit antiserum was prepared against mouse myeloma Protein-315, an IgA protein with specificiy toward the 2,4-dinitrophenyl group. After absorption of the antiserum with another IgA myeloma protein and with affinity-labeled Protein-315, the antiserum was specific for idiotypic determinants on Protein-315. Monovalent ligands that bind to Protein-315 with high affinity strongly inhibited the reaction of the protein with its anti-idiotypic antiserum. This indicated that the region of the hapten-binding site is a major idiotypic determinant. The myeloma protein is thus similar to rabbit antibenzoate antibody in this respect. These results, considered in conjunction with other data in the literature, indicate that an anti-idiotypic antiserum prepared in an isologous or heterologous species can recognize the same determinant, in this case the region comprising the ligand-binding site. Quantitative aspects of the data indicate that there is competition between the hapten and antiidiotypic antibodies for the site.

Animals↗
PubMed1970

Quantitative investigations of idiotypic antibodies. 3. Persistence and variations of idiotypic specificities during the course of immunization.

Changes and persistence of idiotypic specificities of specifically purified rabbit anti-p-azobenzoate antibodies were studied by quantitative methods. In each rabbit idiotypes identified 2 months after the start of immunization were still present in comparable concentrations 2 months later. After month 4, they were replaced by new and unrelated specificities; the changes were abrupt in two rabbits and gradual in the third, and were associated with an increase in the average affinity for specific hapten. In two surviving rabbits the new sets of specificities persisted in part for at least 1 yr. Quantitative changes occurred during this period, and the antibody preparation used as immunogen reacted most effectively with the homologous anti-D serum. The antibody population present at month 17 (D(17)) in one rabbit was deficient in idiotypic specificities present in D(8) and lacked specificities present in D(2), indicating the presence in D(17) of a third group of specificities. The percentage of the antibody population from each rabbit reactive with homologous anti-idiotypic serum was greater at month 8 than at month 2, suggesting a decrease in heterogeneity. Since the donor rabbits were challenged repeatedly with antigen, it appears that, after month 8, a portion of the antigen was utilized to stimulate existing cell lines and a portion to initiate new clones. Precipitation of anti-p-azobenzoate antibodies removed idiotypic specificities, indicating that they were not present on the anti-bovine gamma-globulin antibodies in the same sera.

Animals↗
PubMed1970

Quantitative investigations of idiotypic antibodies. II. Nonprecipitating antibodies.

Idiotypic antibodies were investigated quantitatively by a method of indirect precipitation, which utilizes labeled F(ab')(2) fragments of specifically purified antibenzoate antibody from the donor, anti-antibody, and an antiglobulin reagent. The contribution of allotypic and hidden determinants to these reactions was excluded. Greater fractions of an idiotypic antibody population are precipitated by this method, as compared to direct precipitation, and in two instances large proportions of idiotypic antibodies were detected in populations which failed to form precipitates by double diffusion in agar gel. The greater sensitivity of the indirect method was attributed to its capacity to detect molecules bearing a small number of antigenic determinants. Extensive studies of cross-reactions, carried out by an inhibition technique, failed to reveal any strong reactions of anti-idiotypic antibodies with heterologous antibenzoate antibody preparations, heterologous sera, or IgG, although a few weak cross-reactions were noted. One definite cross-reaction was observed by a direct binding measurement with heterologous antiserum. Antisera prepared in more than one recipient against a single donor preparation reacted with identical or overlapping subpopulations of the donor molecules. Instances in which two recipient antisera reacted with different proportions of the molecules of a single donor provided evidence for the existence of more than one idiotypic antibody population in the antibenzoate antibody of an individual rabbit.

Animals↗
PubMed1970

Evidence for control of synthesis of the varible regions of the heavy chains of immunoglobulins G and M by the same gene.

Previous work indicated that the light chains of a monotypic immunoglobulins G2-K and M-K from a single patient (Ti1) are identical. Our present data show that the monotypic immunoglobulins G and M share idiotypic determinants not present in their isolated light chains or in any of a large number of other immunoglobulins tested, and that amino acid sequences of the first 27 residues from the NH(2)-terminal end of the gamma- and mu-chains are identical. These results support the hypothesis that at least two genes control the synthesis of each heavy and light chain and suggest that the monotypic immunoglobulin G and monotypic immunoglobulin M of this patient share three of the four genes involved. It is proposed that, during normal immunoglobulin synthesis, different cells of a single clone synthesize immunoglobulins M and G, and that the light chains and the variable segments of the heavy chains of the proteins of the two classes are identical within the clone. A genetic switching mechanism is suggested.

Amino Acid Sequence↗
PubMed1970

Quantitative investigations of idiotypic antibodies. IV. Inhibition by specific haptens of the reaction of anti-hapten antibody with its anti-idiotypic antibody.

Rabbit anti-idiotypic antibodies were prepared by injection of specifically purified anti-p-azobenzoate antibodies (D) from individual donor rabbits. Benzoate derivatives were found to be strong inhibitors of the reactions of D with anti-D antisera. There was a close correlation between the combining affinities of the benzoate derivatives used and their effectiveness as inhibitors. Compounds tested that are chemically unrelated to benzoate were ineffective. The results indicate either that the combining site of anti-benzoate antibody is part of an important idiotypic determinant, which is sterically blocked by hapten, or that the hapten induces a conformational change which alters idiotypic determinants not involving the active site. Such conformational changes, if they occur, must be restricted since hapten has little effect on the reactions of F(ab')(2) fragments of anti-benzoate antibodies with antisera directed to rabbit fragment Fab and no detectable effect on reactions with antibodies directed to allotypic determinants.

Animals↗