Age-related susceptibility of naive and memory CD4 T cells to apoptosis induced by IL-2 deprivation or PHA addition.

The increased age-associated incidence of infectious and cancer diseases has been related to the alteration of immune functioning found in the elderly (immunosenescence). The reduction of naive T cells, which determine an impaired ability to mount immune responses to new antigens, represents a hallmark of the aging process. The aim of this study was to evaluate the susceptibility to apoptosis of purified naive and memory CD4(+) T cells from peripheral blood of healthy people ranging in age from 20 to 98 years.

Functional residues on the enzyme active site of glyoxalase I from bovine brain.

Bovine brain glyoxalase I was investigated in order to identify amino acid residues essential for its catalytic activity. This enzyme is a 44-kDa dimeric protein which exhibits a characteristic intrinsic fluorescence, with an emission peak centered at 342 nm. The total of eight tryptophan residues/molecule was estimated by using a fluorescence titration method.

Purification and partial characterization of glyoxalase I from bovine brain.

Glyoxalase I was purified to homogeneity from bovine brain using affinity chromatography on S-hexylglutathione-Sepharose 6B with a yield of 22%. The enzyme was a dimer (44,000 Daltons) composed of, apparently, identical subunits (22,000 Daltons), as shown by SDS electrophoresis, and contained one mole of Zn2+/monomer. The active site metal ion, Zn2+, was removed by dialysis against EDTA, but the activity of the apoenzyme obtained was not completely restored after addition of Co2+ and Zn2+ (<25%), while a recovery of 50% was obtained after addition of Mg2+.