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D C Benjamin

Publications and source records attributed to D C Benjamin.

68 records · Page 4Linked to original sources
PubMed1970

The termination of immunological unresponsiveness to bovine serum albumin in rabbits. I. Quantitative and qualitative response to cross-reacting albumins.

Rabbits made unresponsive to BSA at birth were given two courses of immunization with various cross-reacting albumins at 3 months of age. Normal control rabbits, of equivalent age and weight, were similarly immunized. Sera obtained 7 days after the last injection were assayed for binding and precipitating antibody to six albumins and for their avidity for BSA. No significant differences were found between unresponsive and normal rabbits in the amount of antibody reacting with any of the six albumins used. This was the case regardless which albumin was used to terminate the unresponsive state. Avidity differences were seen and seemed to depend on the antigen used and not on the immunological status of the animal. The simultaneous injection of small amounts of BSA inhibited the termination of unresponsiveness. These results were discussed in the light of the more recent theories of the termination of unresponsiveness and of antibody formation.

Animals↗
PubMedDate not supplied

Sequence polymorphisms and antibody binding to the group 2 dust mite allergens.

BACKGROUND: The group 2 allergens Der p 2, Der f 2 and Eur m 2 are 14-kD proteins with > 80% sequence identity. Isoforms within each genus have been identified which differ by 3-4 amino acids. The aim of this study was to investigate the importance of these substitutions to antibody binding. METHODS: Recombinant allergens were expressed and purified from Escherichia coli. ELISA and skin testing were used to evaluate antibody binding. Molecular modeling of the tertiary structure was preformed to examine the location of substitutions. RESULTS: The three Der f 2 isoforms and two of three of the Der p 2 isoforms reacted with all monoclonal antibodies (mAb). Der p 2.0101, the isoform with aspartate at position 114, bound all mAb except 1D8. Substitution of asparagine for aspartate restored binding of rDer p 2.0101 to mAb 1D8 and increased the correlation coefficient for IgE binding from 0.72 to 0.77. The three Der p 2 isoforms showed comparable skin test reactivity to nDer p 2 and commercial extract. rEur m 2.0101 bound to all mAb except 7A1 and when compared with rDer p 2 for IgE binding, r(2) = of 0.58 (n = 72). Lep d 2 did not react with mAb or with Dermatophagoides spp. allergic sera. Modeling revealed that Eur m 2, Lep d 2 and Tyr p 2 retain the tertiary fold of Der p 2 and the substitutions are on the surface. CONCLUSIONS: mAb could distinguish isoform substitutions. IgE binding showed a good correlation among all isoforms, thus the recombinant allergens are useful for diagnosis.

Allergens↗
PubMedDate not supplied

Molecular cloning of German cockroach (Blattella germanica) allergens.

Allergens produced by cockroaches (CRs) are an important cause of IgE antibody responses and asthma. Using molecular cloning and nucleic acid hybridization techniques, we have identified and sequenced several important allergens produced by the German CR (Blattella germanica) and studied their expression in the American CR (Periplaneta americana). Principal allergens include Bla g 2 (36-kD protein) and Bla g 4 (21-kD protein), to which 60-70% of CR-allergic patients make IgE antibodies. Bla g 2 is only expressed by B. germanica, whereas DNA encoding Bla g 4 is present in P. americana, but is not transcribed into mRNA. Sequence homology searches have identified Bla g 2 as an aspartic protease and Bla g 4 as a calycin. Other CR allergens that have been cloned include a glutathione transferase and a troponin. These studies will enable recombinant allergens to be expressed and used to investigate the role of CR allergens in asthma.

Allergens↗