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R Stigler

Publications and source records attributed to R Stigler.

7 recordsLinked to original sources
PubMed2004

Initial salivary pellicle formation on solid substrates studied by AFM.

Organic layers of salivary biopolymers adsorbed on soft and hard oral tissues, referred to also as salivary pellicle, play a critical role with respect to all surface phenomena taking place in the oral cavity. The initial stages of pellicle formation are of great interest since they determine the ensuing processes of salivary biopolymer adsorption and subsequent adherence of bacteria. In spite of the important physiological role of the pellicle in protecting the enamel surface against short-term acidic attacks, the composition and ultrastructure of the pellicle layer are not yet understood and resolved in detail. The present study utilized atomic force microscopy (AFM), for the first time, to elucidate the morphogenesis and ultrastructural pattern of initial salivary pellicle formation taking place in situ on solid substrates of mica, silicon wafer and graphite. Using tapping mode AFM, salivary pellicles were found in all intraorally exposed specimens and revealed a globular surface morphology of the adsorbed protein layer. The average diameter and height of the adsorbed salivary proteins were determined to be 15 +/- 3 nm and 2.0 +/- 0.5 nm, respectively. It was also found that the surface energy of the substrates affects the rate of pellicle formation, while the overall size of the adsorbed salivary proteins appears to be identical on all studied substrates.

Adsorption↗
PubMed1995

Glycosylation analysis of a polyreactive human monoclonal IgG antibody derived from a human-mouse heterohybridoma.

Glycosylation of the human monoclonal IgG1 lambda antibody (mAb) CBGA1 was analysed by lectin blotting. The CBGA1 antibody binds to several antigens including donor self antigens, as detected by ELISA immunoblotting techniques and an erythrocyte binding assay. The mAb producing cell line was obtained by EBV transformation of peripheral blood lymphocytes of a healthy donor followed by fusion to the heteromyeloma cell line, CB-F7. The resulting heterohybridoma was cultivated in a hollow fibre bioreactor system. A bulk pool of 0.9 g antibody was produced. Fab and Fc fragments of the purified mAb were prepared and analysed. A noteworthy heterogeneity of CBGA1 and its fragments in SDS-PAGE and IEF was detected. We found glycosylation in the Fab fragment of CBGA1 in addition to the conserved glycosylation site in the Fc fragment at Asn 297. Fab glycosylation was detected in both the Fd region and the lambda-chain. The glycosylation pattern of the gamma-chain differs from that of the lambda-chain. Sequence analysis of the VH gene shows a potential N-glycosylation site located in framework III at position Asn 75.

Animals↗
PubMed1994

Identification and characterization of a TNF alpha antagonist derived from a monoclonal antibody.

Peptides derived from the CDRs of the anti-TNF alpha monoclonal antibody Di62 were tested for inhibition of binding of Di62 to TNF alpha as well as of TNF alpha to its 55 and 75 kDa receptor. A peptide derived from the CDR1 of the light chain was shown to specifically inhibit Di62 binding to TNF alpha with markedly higher activity (Ki = 4 microM) than all other CDR-derived peptides. This peptide also significantly inhibited binding of TNF alpha to its 55 and 75 kDa receptor and protected L929 cells from the cytotoxic effect of TNF alpha (IC50 = 6 microM). The C-terminal region of this peptide, which is homologous to the 55 and 75 kDa TNF receptor, was found to be essential for activity.

Amino Acid Sequence↗
PubMed1993

Structural base of the interaction of a monoclonal antibody against p24 of HIV-1 with its peptide epitope.

The interaction of a murine monoclonal antibody (CB 4-1) against the core protein p24 of HIV-1 with its peptide antigen was studied in detail. The amino acid sequence of the variable regions of the heavy and light chain as derived from DNA sequencing was used to model the structure of the antigen binding region on the basis of reported Fab structures from the Brookhaven Protein Data Base. A linear peptide epitope responsible for the p24 binding to the antibody was determined by peptide scan. Subsequent N- and C-terminal truncation of the corresponding sequence region as well as amino acid substitutions were performed to recognize the epitope and the amino acid residues critical for antibody binding. These data were used to derive a structural model of the peptide-antibody interaction.

Amino Acid Sequence↗