Effect of serine proteinase from Staphylococcus aureus on in vitro stimulation of human lymphocytes

Abstract

In a broad concentration range (0.1-100 micrograms/ml) the serine proteinase (SP) from Staphylococcus aureus has no cytotoxic effect on human peripheral blood lymphocytes and does not stimulate them in culture. However, it affects the action of a number of polyclonal activators. In a concentration of 100 micrograms/ml SP completely eliminates blastic transformation after stimulation with B cell mitogens (NDCM, S. aureus and Escherichia coli), lowers the blastic transformation after stimulation with PWM and SPA, and does not affect the blastic transformation after stimulation with PHA. SP (100 micrograms/ml) reduces the concentration of Ig in stimulated cultures (stimulation with PWM, NDCM, S. aureus and E. coli) far below the Ig level of unstimulated controls. This effect can be ascribed to an influence on cell stimulation, not to the proteolytic cleavage of secreted Ig, although SP can partially digest Ig. The effect on lymphocyte stimulation takes place when the SP is added to the culture together with the mitogen, or 18 h after the mitogen. This implies that SP does not affect the first stage of stimulation.

Identification of Secreted Exoproteome Fingerprints of Highly-Virulent and Non-Virulent Staphylococcus aureus Strains

“…This fact was at first unexpected, since staphylococcal proteases have been widely implicated in virulence. In particular, a number of reports consistently suggested the role of SSPA in staphylococcal virulence based on certain in vitro properties and indirect observations (Prokešová et al, 1988 , 1992 ; Karlsson et al, 2001 ) However, the data from in vivo models is relatively inconclusive (Coulter et al, 1998 ; Rice et al, 2001 ), clearly indicating only that although a single protease gene knock-out may not change the virulence, the orchestrated action of multiple secreted staphylococcal proteases may have an profound effect on the growth and survival of S. aureus in the infected host (Kolar et al, 2013 ). Therefore, advanced combination knock-outs are needed to unambiguously indicate the role of particular proteases in staphylococcal virulence.…”

Plasma erythritol and cardiovascular risk: is there evidence for an association with dietary intake?

“…Interestingly, endogenous erythritol synthesis is also elevated in response to oxidative stress ( 6 ). It is known that the pentose-phosphate pathway is more active in subjects with pre-existing cardiovascular disease ( 1 , 7 ). This could therefore explain the elevated erythritol concentrations measured in the cohorts, without consumption via food being a factor.…”

Extracellular Proteases of Staphylococcus spp.

“…The protease efficiently inactivates α 1 -proteinase inhibitor (α 1 -PI) -the major, potent neutrophil elastase inhibitor of human plasma -by specific cleavage at the exposed reactive site loop. Similarly, although in vitro the enzyme affects the action of polyclonal activators on lymphocytes, the mechanism and in vivo significance of this activity are unknown (Prokešová et al, 1988). Generation of kinin directly from high molecular weight kininogen by V8 protease was demonstrated.…”