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Biomedical subjects

A A Benedict

Publications and source records attributed to A A Benedict.

At least 37 records · Page 2Linked to original sources
PubMed1977

Chicken high molecular weight immunoglobulin (IgM) allotypes: localization on the heavy chains and proposed nomenclature.

An alloantiserum recognizing a genetic marker (CM-1.4) on chicken 17S Ig was generated by immunizing jungle fowl with Salmonella O-anti-Salmonella O (UCD 3) agglutinates. Specificities CM-1.4 and M1a were present on 7S subunits and H chains based on their ability to inhibit in RIA the binding of alloantibody (anti-CM-1.4 or anti-M1a) to UCD 3 125I-17S Ig. CM-1.4 appears to be fully expressed on 7S subunits but is altered on H chains. In contrast, anti-M1a bound both 7S subunits and H chains with decreased avidity indicating that the M1a specificity was altered in both preparations. Since CM-1.4 and M1a are present on 17S Ig H chains, and absent from 7S Ig, they probably represent allotypic markers in the constant region of 17S Ig H chains. Having assigned two 17S Ig allotypic specificities to H chains, we propose that the locus controlling their expression be called CM-1. Based on the distribution of the CM-1.4 and M1a allotypes in inbred lines of chickens, 3 alleles are defined at the CM-1 locus.

Alleles↗
PubMed1977

Structural and genetic studies on chicken 7S immunoglobulin allotypes. II. Distribution of allotypes on the 7S immunoglobulin of homozygous and heterozygous chickens.

We have previously reported that chicken 7S immunoglobulin (Ig) heavy (H) chain allotypes (CS-1 locus) segregate as phenogroups in F2 progeny. Specificity CS-1.1 formed a phenogroup with CS-1.4 in inbred chicken line UCD 2, and a second phenogroup with CS-1.3 in line UCD 3. To determine whether these phenogroups were formed by combinations of specificities on the same, or on separate subclasses of 7S Ig, their distribution on the 7S Ig molecules of birds homozygous for 7S Ig allotypes was analyzed by radioimmunoassay. Anti-CS-1.1 and anti-CS-1.3 alloantisera each bound more than 94% of line UCD 3 1252-7S Ig. Similar results were obtained with alloantisera to CS-1.1 and CS-1.4 WITH 125 I-7S Ig from line UCD 2. These results indicate that both phenogroups were formed by combinations of specificities present on the same H chain. Thus, each phenogroup described, probably is the product of a single structural gene which is responsible for more than 94% of the 7S Ig H chain constant regions. In F hybrids with the genotype CS-1.3, 1.3/CS-1.2, two populations of serum 7S Ig molecules were detected by direct and sequential binding analysis with specific alloantisera. One population of 7S Ig contained specificities CS-1.1 AND CS-1.3, but not CS-1.2; while the second population was exclusively the product of one parental allele. Consistent with a genetic regulatory mechanism involving allelic exclusion, no MS Ig containing allotypes produced by both alleles was detected.

Animals↗
PubMed1977

Structural and genetic studies on chicken 7S immunoglobulin allotypes. III. Proposed nomenclature for the CS-1 gene alleles.

A survey of 47 inbred or partially inbred chicken lines derived from five sources in the United States and Europe revealed considerable genetic polymorphism in the structural gene (CS-1) responsible for the production of the predominant chicken 7S Ig heavy chain. A minimum of 10 alleles of the CS-1 gene were detected as unique combinations or phenogroups of CS-1 specificities. A system of nomenclature for CS-1 alleles was developed and six homozygous lines were designated as prototype lines. The remaining four CS-1 alleles occurred only in lines that were polymorphic for 7S Ig allotypic specificities.

Alleles↗
PubMed1976

Association of serum hemolytic complement levels with the major histocompatibility complex in chickens.

The total hemolytic complement (C) levels in inbred line 7 chicks and adults were lower than C levels in inbred lines 2 and 3 and in outbred chickens of the same age. In all birds, adult levels of C were obtained in 5- to 6-wk-old chickens. Analysis of F1 and F3 generations clearly showed that the C level in chickens was determined by a dominant gene(s) associated with the major histocompatibility complex. Finding this association in a nonmammal strengthens the importance of the relationship between closely linked genes controlling histocompatibility, immune responsiveness, mixed leukocyte reaction, and C activity.

Age Factors↗
PubMed1976

Structural and genetic studies on chicken 7S immunoglobulin allotypes. I. Detection of four heavy chain specificities with a new radioimmunoassay.

A method was developed for the detection of allotypes on intact, radiolabeled 7S immunoglobulin (Ig) which does not involve insolubilized alloantisera. Binding of dinitrophenylated anti-allotype (DAA) antiserum with radiolabeled alloantigen was demonstrated by the addition of rabbit anti-dinitrophenyl antiserum followed by precipitation of complexes with sheep anti-rabbit gamma-globulin antiserum. Dinitrophenylation of alloantiserum up to 8.5 hr had no effect on antibody titer or avidity. Binding inhibition assays with the DAA method detected allotypes on 2 to 5 ng of 7S Ig. Four specificities were detected on 7S Ig heavy (H) chains by binding inhibition with the DAA assay. Specificities CS-1.1 and CS-1.2, located in the Fab fragment, were detected at 3- to 5-fold lower concentrations of reassociated H and light (L) chains than on the isolated H chains. On the basis of regression coefficients calculated from binding inhibition curves, the avidity of isolated H chains was significantly increased following reassociation with L chains, indicating that the conformation of CS-1.1 and CS-1.2 determinants depends in part on H and L chain interactions. In contrast, reassociation of H and L chains did not significantly increase H chain inhibitory activity or avidity for specificities CS-1.3 and CS-1.4.

Animals↗
PubMed1975

Radioelectrocomplexing: a counterelectrophoretic method for hapten--antibody interaction.

We have described an application of a radioimmunoassay (RIA)method, known as radioelectrocomplexing (REC), which involves the anodal migration of antigen and the cathodal migration of antibody in agar electrophoresis. The agar is divided into zones of free antigen (DNP125I-HSA) and antigen bound with anti-DNP. Complete assays of anti-DNP can be performed in 2-4 hr since both immune complex formation and separation of free from bound antigen can be accomplished by electrophoresis in 60-90 min. Estimation of the weight of specifically-purified anti-DNP chicken antibodies in the nanogram range by REC is of the same order as the reported sensitivity of other RIA methods. The method was capable of demonstrating the higher avidity of the 17 S than 7 S antibody. Based on hapten inhibition the relative binding constants of DNP derivatives and anti-DNP were of the same order as reported from more definitive methods.

Animals↗
PubMed1975

Elevated 7S immunoglobulin and acute phase proteins in adjuvant-injected chickens.

Injection of chickens with FCA or FIA supplemented with either Bordetella pertussis or Nocardia rubra induced greatly increased serum levels of 7S Ig and proteins with alpha-, beta-, and gamma-mobility in electrophoresis. The serum protein changes were correlated with the development of DHS and the formation of a large allergic granuloma. The 7S Ig was considered "nonspecific" since it was not adsorbed with the bacterial cells. The alpha-, beta-, and gamma-mobility proteins were identified as acute phase proteins as they also were induced by injection of chickens with turpentine-oil; however, increased serum levels of 7S Ig were not similarly increased.

Animals↗
PubMed1975

Class, amounts and affinities of anti-dinitrophenyl antibodies in chickens. I. Production of 7S and 17S antibodies of equal affinity by intravenous injection of antigen.

Repeated intravenous injections of maximally coupled dinitrophenylated bovine gamma-globulin elicited both 7S and 17S anti-dinitrophenyl antibodies in chickens. Only antibodies of low affinity were produced regardless of the priming dose, the interval between injections, and the number of injections. The 7S and 17S antibodies isolated from invididual animals had identical affinities and heterogeneity indices. The concentrations of antibodies formed were uniformly low despite many injections over a prolonged period. These studies indicate that stimulation by antigen alone may not be sufficient for the induction of predominant 7S antibody formation and for the synthesis of high affinity antibody.

Adsorption↗
PubMed1975

Class, amounts, and affinities of anti-dinitrophenyl antibodies in chickens. II. Production of a restricted population of high affinity 7S antibodies by injection of antigen emulsified in adjuvant.

The response of chickens given a single intramuscular injection of maximally coupled dinitrophenylated-gamma-bovine beta-globulin in either Freund's complete (FCA) or incomplete (FIA) adjuvants was characterized by an initial synthesis of 7S and 17S antibodies followed by the exclusive and persistent production of 7S antibodies. The 17S antibodies were not detected either 3 to 4 weeks after a single injection or after an intravenous boost 16 months later. Injections of low doses of antigen in FCA induced the synthesis of 7S antibodies of high affinity at least by 4 months. Analyses of the Sips plots generated from equilibrium dialysis data indicated that a shift in the distribution of 7S antibody affinities occurred because of the production of a restricted population of high affinity antibodies. The changes in the binding properties of antibody during the immune response from chickens given antigen in FIA were less apparent, although qualitatively similar, to those found in birds given antigen in FCA. Three possibilities were presented to explain the effect of adjuvant on the class and affinity of the antibody: a) the requirement of a second signal for B cell differentiation, b) the presence of subpopulation of B cells, and c) somatic mutation events.

Animals↗