Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Antibody Affinity”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1979

The genetic control of antibody affinity. Evidence from breeding studies with mice selectively bred for either high or low affinity antibody production.

The genetic control of antibody affinity has been studied in mice selectively bred on the basis of the affinity of antibody they produce to protein antigens injected in saline. Two lines of mice have been obtained, one producing predominantly high and the other predominantly low affinity antibody. Breeding experiments have been performed with these two lines after ten generations of selection and the level and affinity of antibody to protein measured in parents, F1 hybrids and backcross offspring. The results indicate that antibody affinity is a genetically controlled parameter of the immune response and that this control is exerted independently of that controlling antibody levels. Furthermore, high and low affinity line mice have been typed for major histocompatibility complex antigens and the results show that the two lines are not significantly different. This therefore suggests that genes controlling antibody affinity are not linked to the major histocompatibility locus.

Animals↗
PubMed1976

Evidence for the genetic control of antibody affinity from breeding studies with inbred mouse strains producing high and low affinity antibody.

The amount (Abt) and relative affinity (KR) of antibody produced in response to protein antigens injected in saline has been measured in the parents, F1 hybrids and backcross offspring of inbred mice which produce high and low KR antibody to these antigens. The results obtained support the view that antibody affinity is under polygenic control. Furthermore, strain related variation in Abt is independent of KR and the breeding experiments indicate that these two parameters are under independent genetic control.

Animals↗
PubMed1992

Correlation between antibody affinity and serum bactericidal activity in infants.

Nearly one-half of infants immunized with Haemophilus influenzae b capsular polysaccharide (polyribosylribitol phosphate; PRP)-protein conjugate produce low-affinity antibody. To test the hypothesis that antibody affinity is linked to biologic function, sera were obtained before and 1 month after immunization of 18-month-old infants with PRP-diphtheria toxoid conjugate vaccine. Correlation was attempted of anti-PRP affinity, concentrations of anti-PRP, and anti-outer membrane proteins and of immunoglobulin isotype with bactericidal activity. Nine subjects produced anti-PRP of low affinity (K less than 10(4) l/mol), and 11 had higher affinity antibodies (average K, 2.8 x 10(4) l/mol). By multiple regression analysis, antibody affinity was the only variable significantly related to the bactericidal activity of serum after immunization with the conjugate vaccine (r = .71; P = .04). Thus, serum anti-PRP from a substantial proportion of infants appeared functionally deficient in association with low-affinity antibody.

Antibodies, Bacterial↗
PubMed1987

A quantitative relationship between antibody affinity and antibody avidity.

The relationship between antibody avidity, measured by the dissociation of the antigen-antibody bond in antigen excess, and antibody affinity was studied. Complexes of radiolabelled antigen and antibody of known affinity were prepared in vitro and allowed to stand for seven days to reach equilibrium. Then nonlabelled antigen in one hundred fold excess was added to dissociate the complexes. After an appropriate incubation the fraction of antigen bound to antibody was measured by the ammonium sulfate precipitation method. The dissociation index was the fraction bound in the experimental sample divided by the fraction bound in the control. The correlation coefficient between the dissociation index and the antibody binding constant was 0.92 for early dissociation and 0.98 for late dissociation. The regression equation relating the binding constant to the dissociation index was K = 6.4(DI) + 6.25, where DI is the late dissociation index and K is the logarithm to the base 10 of the binding constant. There is a high correlation between avidity and affinity of antibody. Antibody affinity can be estimated from avidity data. The stability of antigen-antibody complexes can be predicted from antibody affinity.

Animals↗
PubMed1984

Glomerulonephritis: the use of grafted hybridomas to investigate the role of epitope density, antibody affinity and antibody isotype in active serum sickness.

Two experimental models were used to investigate the role of antigen epitope density, antibody isotype and antibody affinity in immune-complex glomerulonephritis. In both models, two antigens were used: dinitrophenylated bovine serum albumin of high and low substitution ( DNP19BSA and DNP4BSA , respectively). In the first, acute actively induced model, a single intravenous injection of either of the two antigens was given to mice bearing hybridomas that secreted one of five monoclonal antibodies--four IgGl with varying affinities for the dinitrophenol hapten, and an IgM antibody with a similar affinity to that of the lowest affinity IgGl. The second, chronic actively induced model was similar, except that mice were immunosuppressed to reduce interference by the hosts' antibody responses and that 15 daily intraperitoneal injections of antigen were given. The immunofluorescent findings in both models were similar. Glomerular deposition of antibody and antigen in mice with high affinity IgG or low affinity IgM antibodies was mesangial when DNP4BSA or DNP19BSA was injected. However in mice with the lowest affinity IgG antibodies, deposition was extensive and predominantly capillary when DNP19BSA was injected but was minimal when DNP4BSA was injected. The relevance of these findings to the pathogenesis of glomerulonephritis is discussed.

Acute Disease↗
PubMed2006

A study of the structural correlates of affinity maturation: antibody affinity as a function of chemical interactions, structural plasticity and stability.

Mutations introduced in an antibody germline sequence as a result of somatic hypermutation could cause its derivatives to have an altered affinity for its target. Affinity maturation favors the selection of the antibodies which exhibit increased affinity. The mutations in 80 high affinity anti-thyroid peroxidase sequences derived from six germlines were analysed in terms of the physicochemical properties of the replacement residues, namely hydrophilicity, size and polarizability, and charge and polarity, in the context of its position and probable solvent accessibility. The effects of these substitutions were evaluated in terms of the resultant increased chemical interactivity potential of the affinity-matured antibodies relative to the germline. The results of the analysis would be useful in the rational design of antibodies and of other proteins for improved binding properties.

Amino Acid Sequence↗
PubMed1983

The measurement of antibody affinity: a comparison of five techniques utilizing a panel of monoclonal anti-DNP antibodies and the effect of high affinity antibody on the measurement of low affinity antibody.

The affinities of 9 IgG1 monoclonal anti-dinitrophenol (DNP) antibodies for 3H-epsilon-DNP-L-lysine, 125I-HOP-DNP-L-lysine and 125I-DNP-human serum albumin (HSA) were determined. 3H-DNP-lysine was used in equilibrium dialysis and ammonium sulphate globulin precipitation assays; 125I-HOP-DNP-lysine was used in equilibrium dialysis and polyethylene glycol precipitation; and 125I-DNP5-HSA in the polyethylene glycol precipitation assay for affinity. The ranking order of the monoclonal antibodies in terms of affinity by the assays was significantly correlated. Of particular importance was the observation that the simple and widely applicable globulin precipitation assay utilizing a protein antigen produced affinity values which showed concordance with the least equivocal but cumbersome assay, equilibrium dialysis. Mixing of antibodies of high and low affinity demonstrated that even a low proportion of high affinity antibody had marked effect on measurements of the amount and affinity of a predominantly low affinity antibody preparation.

Animals↗
PubMed2006

Latest technologies for the enhancement of antibody affinity.

High affinity antibodies are crucial both for the discovery and validation of biomarkers for human health and disease and as clinical diagnostic and therapeutic reagents. This review describes some of the latest technologies for the design, mutation and selection of high affinity antibodies that provide a paradigm for molecular evolution of a far wider range of proteins including enzymes. Strategies include both in vivo and in vitro methods and embrace the latest concepts for antibody display and selection. Specifically, affinity enhancement can be tailored to the target-binding surface, typically the complementary determining region (CDR) loops in antibodies, whereas enhanced stability, expression or catalytic properties can be affected by selected changes to the core protein scaffold. Together, these technologies provide a rapid and powerful strategy to drive the next generation of protein-based reagents for numerous clinical, environmental and agribusiness applications.

Animals↗
PubMed1998

Low antigen dose favours selection of somatic mutants with hallmarks of antibody affinity maturation.

The immunization schedule is critical for the derivation of high-affinity antibodies, low antigen dose being particularly favourable for the development of a more efficient memory response. To analyse the molecular events underpinning this preference, we analysed the early maturation of the response to the hapten 2-phenyloxazolone (phOx) using low and high doses of immunogen. The phOx response is initially dominated by antibodies expressing the VkOx1-Jk5 light chain and the hallmark of the early stages of maturation is the substitution of His 34 by Asn or Gln increasing affinity 10- or eightfold, respectively, and of Tyr 36 by Phe. High-affinity antibodies express mutations at both sites. We cloned and sequenced VkOx1-Jk5 light chains from antigen-specific B cells taken 14 and 21 days after immunization with high and low antigen doses. We found that overall, the derived sequences were more mutated both at longer times and at higher dose. At day 14, His 34 was more frequently mutated at the higher than at the lower dose, while at day 21 the reverse was true. On the other hand, the His 34/Tyr 36 mutation pair was more frequent at low than high doses at both 14 and 21 days. Furthermore, at both times, the low immunization protocol yielded double mutants in cells with a lower mutation background. It appears therefore that while the higher dose may favour the acquisition of individual critical mutations, low-dose immunization favours the selection of a more focused mutational pattern, whereby advantageous mutations are associated with a low mutational background.

Animals↗
PubMed1991

Induction of leukotriene production before antigen challenge enhances antibody affinity in genetically selected mice.

Mice genetically selected for their incapacity to produce high-affinity antibody to protein antigens in adjuvant (nonmaturing (NM) mice) were treated with indomethacin, an inhibitor of the cyclooxygenase pathway of arachidonic acid metabolism. Pretreatment with indomethacin significantly enhanced the affinity of antibodies produced 21 days after immunization with human serum albumin (HSA). Blockage of the cyclooxygenase pathway in this way was shown to induce the production of leukotrienes via the lipoxygenase pathway. The production of leukotrienes may well be responsible for the enhanced antibody affinity, since blockage of the lipoxygenase pathway in addition to the cyclooxygenase pathway reversed the effect. In an attempt to elucidate the mechanisms involved, IL-1 production and Ia expression by macrophages were examined. Ia expression by peritoneal cells from untreated NM mice was significantly lower than that by their high-affinity-producing counterparts 3 days after immunization. Indomethacin pretreatment raised inducible Ia antigen levels on macrophages of NM mice to those seen on cells from untreated high-affinity mice. Indomethacin treatment alone induced the production of IL-1 by macrophages in NM mice. However, 3 days after immunization and the withdrawal of indomethacin in NM mice, IL-1 production was significantly lower than the response of NM mice given antigen alone, suggestive of the induction of a feedback mechanism. Thus indomethacin pretreatment results in a cascade of events in macrophages which produce a decrease in IL-1 production and an increase in inducible Ia expression 3 days after antigen challenge.

Animals↗
PubMed1979

Antibody affinity and clearance function studies in high and low antibody affinity mice. The effect of protein deficiency.

The effect of dietary manipulation on the relationship between macrophage clearance function and antibody affinity has been investigated in genetically selected high and low affinity mice. The results confirm that protein deprivation reduces the clearance rate of polyvinylpyrrolidone (Kpvp) and the relative affinity (Kr) of antibody to human serum albumin in mice normally producing high affinity antibody. Although protein deprivation of mice of the low affinity line reduced Kpvp, the mean Kr was not altered. Furthermore, although the two lines had significant differences in Kr values there were no demonstrable differences in macrophage clearance function as assessed by clearance of PVP, radiolabelled aggregated IgG and preformed antigen-antibody complexes. Analysis of values of Kr and Kpvp in individual animals indicated that these two parameters are not correlated. These experiments, provide further evidence for the profound effect of dietary manipulation on the immune response and suggest that in these genetically selected mice at least, the genetic control of antibody affinity is exerted at a level other than that measured by macrophage clearance function tests.

Animals↗
PubMed1975

Demonstration of an antibody-mediated tolerance state and its effect on antibody affinity.

We have described a model of immunological tolerance induced, in adult mice, by a single injection of a moderate dose of a hapten-protein conjugate. The data suggest that the mechanism of this tolerance state is the production of small amounts of high affinity antibody in response to the tolerance-inducing antigen injection. This antibody acts to inhibit the response to a subsequent challenge with antigen in complete Freund's adjuvant by a mechanism comparable to that of passive antibody-medicated immune suppression. It was shown that a small but high affinity. Tolerance was not terminated by transfer of normal syngeneic spleen or peritoneal cells into tolerant animals. Spleen cells from tolerant mice, when transferred into lethally irradiated, syngeneic animals, produced a PFC response which is greater in magnitude and tolerance state had a significant degree of carrier specificity which was shown to be comparable to the carrier specificity of antibody-mediated immune suppression. hus, evidence was presented to show that one mechanism of tolerance in adult animals in the suppressive effect of small amounts of high affinity antibody formed in response to the tolerizing injection of antigen.

Animals↗
PubMed1979

Chronic immune complex disease in mice: the role of antibody affinity.

Two lines of mice selectively bred for producing high and low affinity antibody to protein antigens were repeatedly injected with human serum albumin and the severity and pattern of immune complex disease induced in this way was studied in the two lines. In low affinity mice, there was a greater intensity of deposits in the glomeruli shown by immunofluorescence, and more antibody was eluted from kidney homogenates compared to high affinity line mice. In the low affinity mice, complexes were mainly on the basement membrane whereas in high affinity mice, the localization of immune complexes was predominantly mesangial. However, no significant difference in glomerular filtration rates between the two lines was obtained. The immunopathological significance of antibody affinity is discussed in the light of these results.

Animals↗
PubMed1984

Influence of antibody affinity on the performance of different antibody assays.

The effect of antibody affinity on the performance of 5 commonly used assays was studied. The assays used were measurement of antigen binding capacity in a Farr type assay, haemagglutination, solid-phase radioimmunoassay (SP-RIA), solid-phase ELISA and precipitation. The first 4 assays were all more sensitive for high affinity antibodies. Precipitation was not related to affinity, suggesting that factors secondary to antigen-antibody binding may be more important in determining the level of precipitate formation. The effect of epitope density of the antigen was also investigated in the SP-RIA and ELISA. Affinity dependence was more marked when antigen of low epitope density was used and this dependence could be reduced in the ELISA by choosing a low OD endpoint. Thus, the most reliable way to estimate antibody content by the ELISA may be to determine a low OD endpoint titre against antigen of high epitope density. When epitope density per molecule cannot be increased, an alternative approach to the problem is to increase epitope density by covalent coupling of antigen to the solid-phase rather than by adsorption.

Animals↗
PubMed1994

Low antibody affinity restricted to the IgA isotype in IgA nephropathy.

Antibody affinity affects the handling and behaviour of immune complexes, and experimental studies have shown that animals which produce predominantly low-affinity antibody are prone to immune complex deposition resulting in glomerulonephritis. In order to investigate the potential role of antibody affinity in the pathogenesis of IgA nephropathy, affinity of both IgA and IgG antibody isotypes during secondary response to systemic immunization with tetanus toxoid was studied in 20 patients with IgA nephropathy. Patients with IgA nephropathy produced IgA antibodies of significantly lower affinity than controls (P < 0.001), whereas IgG antibody affinities were similar. Contrasting with controls, patients' IgA antibody affinity was inversely related to antibody concentration, with higher responders producing large amounts of low-affinity antibody. IgG antibody affinity increased with time, and maturation of IgG antibody affinity was similar in both controls and patients. IgA affinity in controls decreased with time, and this lack of IgA affinity maturation may explain the relative unimportance of IgA in normal systemic immunity. This temporal decrease in IgA affinity was not observed in patients with IgA nephropathy. The production of low-affinity IgA in IgA nephropathy may provide an explanation for the predominant deposition of IgA in this disease.

Adolescent↗