Sulfhydryl groups generated by macrophages into the culture medium

Macrophages Can Decrease the Level of Cholesteryl Ester Hydroperoxides in Low Density Lipoprotein

“…However, they may contribute to the process by providing reducing equivalents to a protein (26,28). The latter could also be mediated by thioredoxin, which could act either extracellularly (47) or in association with the cell surface (48); however, this was not investigated in the present study.…”

“…However, when 10 M reduced glutathione was added to the cell-conditioned medium incubated with LDL, the loss of CEOOH increased by an additional 11.6%. From these results we can suggest that the stimulatory effect of cystine on CEOOH degradation by cells or cell-conditioned medium was probably due to its reported capacity to enhance generation of extracellular protein thiols (26,28), which have been shown to be more resistant to autoxidation than free low molecular weight thiols (26,28). The stimulatory effect of GSH on LDL CEOOH degradation seen in cell-conditioned medium could be explained by the same mechanism.…”

“…The latter could also be mediated by thioredoxin, which could act either extracellularly (47) or in association with the cell surface (48); however, this was not investigated in the present study. Protein-associated sulfhydryl groups are more resistant to autoxidation than LMW thiols (26,28) and therefore may be present at levels necessary for CEOOH degrading activity. Cystine in the culture medium probably helps to maintain the required level of protein-bound thiols in the medium, thus explaining its stimulatory effect on CEOOH degradation by cells or cell-conditioned medium.…”

“…It has been demonstrated that cells release sulfhydryl compounds into the medium and can reduce extracellular disulfides such as protein disulfides or cystine (22, 26 -28). Cells can utilize extracellular cystine to produce cysteine (26,27,29) which upon release into the medium can generate sulfhydryl groups on proteins via sulfhydryl-disulfide exchange reactions (26,28); this implicates cystine as an intermediate in protein disulfide reduction.…”

Megemlékezés Földes István mikrobiológus, az orvostudomány doktora születésének centenáriumán • A Tribute to István Földes, DSc, Microbiologist on the Centenary of his Birth

“…Itt épült ki, Földes professzor úr irányításával, Magyarország első speciális HIV-laboratóriuma, ahol a Nemzeti AIDS Bizottság támogatásával professzionális szinten foglalkoztak az AIDS kórokozójának kimutatásával (HIV-verifikálás: a HIV-szűrőlaboratóriumokban reaktívnak vagy gyanúsnak talált szérumminták megerősítő vizsgálata), valamint az embert és más főemlősöket fertőző retrovírusok kutatásával (Földes, 1987). A HIV-vizsgálatokkal párhuzamosan tovább folytatódtak az OEK-MKCS más irányú kutatási projektjei (Karcag et al, 1987;Jókay et al, 1988;Premecz et al, 1989).…”