Mascha Binder | PubMed Health

PubMed2006

The epitope recognized by rituximab.

Rituximab is a monoclonal antibody widely used in the treatment of malignant lymphoma and autoimmunity. Its epitope within the B-cell antigen CD20 is largely unknown. We used phage display libraries to select peptides binding to rituximab. Enriched peptides showed 2 sequence patterns: one motif (CALMIANSC) is related to (170)ANPS(173) within CD20, while another motif (WEWTI) may mimic the CD20 segment (182)YCYSI(185). Phages displaying either motif specifically bound rituximab. Binding to rituximab by the CD20 peptides ANPS and YCYSI was weak when used separately and enhanced when both peptides were linked. Recombinant CD20 extracellular loop proteins blocked binding of the selected CWWEWTIGC phage to rituximab, suggesting that CWWEWTIGC mimics the epitope. Blocking capacity was strongly reduced upon mutation of the CD20 strings ANPS or YCYSI. We conclude that rituximab binds a discontinuous epitope in CD20, comprised of (170)ANPS(173) and (182)YCYSI(185), with both strings brought in steric proximity by a disulfide bridge between C(167) and C(183).

Amino Acid Sequence↗

PubMed2005

The effects of a 45x potency of arsenicum album on wheat seedling growth -- a reproduction trial.

BACKGROUND: Independent replications of preclinical investigations of homeopathic potencies are rare. However, they are a necessary tool to determine the relevant factors modulating the effects of homeopathic potencies in preclinical systems. OBJECTIVE: The goal of the present study was to reproduce a trial published in 1997. An Italian group of researchers investigated the effect of Arsenicum album 45x on the growth of wheat which had been previously poisoned with a material dose of Arsenicum album. The homeopathic treatment was associated with increased wheat shoot growth significantly different from the control group (+24%, p < 0.001). MATERIALS AND METHODS: Wheat poisoned with a sublethal dose of Arsenicum album was cultivated in either Arsenicum album 45x, water 45x, or unpotentized water. After 7 days, shoot length was measured. Reproducibility was assessed in eight independent experiments. RESULTS: Arsenicum album 45x significantly inhibited wheat shoot growth (-3%) compared to treatment with unpotentized water and water 45x (p = 0.011 and p = 0.037). Within the experimental series performed in this reproduction trial, the effects of Arsenicum album 45x proofed to be reproducible. The wheat seed species used did not seem to have a significant impact on the experimental outcome. CONCLUSION: The result of this replication trial is a reversal of the original study, since Arsenicum album 45x inhibited wheat shoot growth instead of enhancing it. Nevertheless, high homeopathic potencies may induce statistically significant effects in biological systems. However, the magnitude and direction of these effects seem to depend on yet unknown parameters.

Arsenic Trioxide↗