Biomedical subjects

C Rabourdin-Combe

Publications and source records attributed to C Rabourdin-Combe.

74 records · Page 5Linked to original sources

PubMedDate not supplied

Regulation of antibody synthesis to sheep red cells in cultures of nu/nu spleen cells by T-cell replacing factor (TRF) and immunoglobulin-binding factor (IBF).

Fc receptor positive alloantigen-activated T cells release an immunoglobulin binding factor (IBF) which suppresses in vitro antibody synthesis. The present work was undertaken to approach the mechanisms by which IBF suppresses the response, and we obtained the following results. First, IBF does not inhibit DNA synthesis in lipopolysaccharide stimulated spleen cells while suppressing the polyclonal plaque response, indicating that IBF does not interfere with B-cell proliferation. Second, antibody synthesis by spleen cells from Nude (nu/nu) mice, stimulated with sheep red blood cells triggered by concanavalin A induced T-cell replacing factor (TRF) was suppressed by IBF, indicating that the factor does not need mature T cells to express its activity. Kinetics experiments showed that IBF does not destroy TRF but rather acts sequentially with the helper factor on the late phase of the differentiation of B cells to antibody producing cells.

Animals↗

PubMedDate not supplied

Substitution of peptide bond 53-54 of HEL(52-61) with an ethylene bond rather than reduced peptide bond is tolerated by an MHC-II restricted T cell.

To probe the interactions between major histocompatibility class-II molecules and the amide bonds of the antigenic peptide main chain, we synthesized ethylenic and reduced analogues of HEL(52-61), an immunogenic peptide for murine major histocompatibility class-II IA k restricted T-cell clones. The synthesis of the corresponding ethylenic analogue of HEL(52-61) in position 53-54 was performed by coupling the Fmoc-protected tripeptide Asp-Tyr-psi [E, CH = CH]Gly with HEL(55-61). Biological tests showed that the ethylenic peptide was presented by major histocompatibility class-II IA kappa molecule and recognized by HEL(52-61)-specific T-cell clones. The corresponding reduced peptide of HEL(52-61) at position 53-54 neither stimulated T-cell clones nor competed with the natural peptide. These results show that, while reduced pseudopeptides might not be appropriate, ethylenic pseudopeptides may be used as probes to dissect the role of hydrogen bonding between the peptide main chain and MHC residues and also help in the design of more stable immunogenic peptides.

Animals↗