Inhibition of the anti-CD3-induced T cell proliferation by crosslinking of stimulatory antibodies in the presence of PMA and interleukin-2.

Anti-CD3 antibodies are directed to the nonpolymorphic part of the T cell receptor complex and may activate human peripheral T cells. Under some circumstances crosslinked anti-CD3 has been described to augment the proliferative response. Here we demonstrate that crosslinking of stimulatory anti-CD3 antibodies by anti-IgG in cell suspension abolishes their effect on proliferation of human resting peripheral T cells in the presence of PMA and/or IL-2.

Adaptation of an HPLC system for transient-state enzyme kinetic experiments: pulse-flow method.

The components of an HPLC system can be easily reassembled into an instrument for transient-state enzyme kinetic experiments based on the continuous-flow technique. The scheme of reassembly, operation and data evaluation is described in detail for the Pharmacia FPLC system. The working quality of the suggested scheme was tested using a well-studied process of bacterial beta-galactosidase activation by Mg2+ ions.

High-performance ion-exchange chromatography of oligoribonucleotides using linear and hyperbolic salt gradients.

A method for separation and chain length determination of oligo- and polynucleotides by high-performance anion-exchange chromatography was developed, which allows resolution of individual fragments according to their chain length n, up to n approximately 10 by linear gradient of sodium chloride and up to n approximately 30 by an hyperbolic gradient of this salt. The hyperbolic relationship between n and the salt concentration at which elution of the fragment occurs allows determination of the degree of polymerization of oligo- and polynucleotides with unknown n. The method proposed can be used for estimation of the effective charge of nucleic acids with complex structure.