Premium
Streptolysin O and adherence synergistically modulate proinflammatory responses of keratinocytes to group A streptococci
Author(s) -
Ruiz Natividad,
Wang Bei,
Pentland Alice,
Caparon Michael
Publication year - 1998
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1998.00681.x
Subject(s) - streptolysin , biology , proinflammatory cytokine , microbiology and biotechnology , streptococcus pyogenes , bacterial adhesin , hacat , keratinocyte , mutant , in vitro , immunology , virulence , inflammation , biochemistry , bacteria , gene , genetics , bacterial protein , staphylococcus aureus
In contrast to a mutant adhesin‐deficient Streptococcus pyogenes (group A streptococcus), its isogenic parental strain binds to human keratinocytes and promotes a vigorous proinflammatory response, characterized by enhanced expression of several cytokines, a more rapid release of prostaglandin E 2 (PGE 2 ) and damage to keratinocyte membranes. However, adherence alone is not sufficient to induce these responses. In this study, we have begun to examine the contribution of other streptococcal products in interactions with keratinocytes by the construction and evaluation of mutants deficient in expression of the secreted pore‐forming haemolysin, streptolysin O (SLO). Inactivation of SLO did not prevent the streptococci from adhering to cultured HaCaT keratinocytes or from expressing an unrelated second streptococcal haemolysin, streptolysin S, during infection of keratinocytes. As measured by a quantitative reverse transcriptase polymerase chain reaction (PCR) assay, inactivation of SLO also did not have a marked effect on the expression of interleukin 1α (IL‐1α) during infection. However, the lack of the ability to produce SLO was associated with a considerable reduction in expression of IL‐1β, IL‐6 and IL‐8 by infected keratinocytes. Measurement of the release of PGE 2 by an enzyme‐linked immunosorbent assay demonstrated that the SLO‐deficient mutants were also not capable of promoting the rapid high level of PGE 2 release characteristic of the adherent SLO‐producing parental strain. Finally, analyses using the fluorescent probe ethidium homodimer‐1 and measurements of release of keratinocyte lactate dehydrogenase indicated that the failure of the SLO‐deficient mutants to induce responses was associated with the failure of these mutants to damage the integrity of the keratinocyte membrane. These data implicate SLO as a factor that acts synergistically with an adhesin to modulate the signalling responses of keratinocytes during infection.