Pro-inflammatory action of LDL(-) on mononuclear cells is counteracted by increased IL10 production.
OBJECTIVE
LDL(-) is a minor LDL subfraction that induces inflammatory factor release by endothelial cells. Since LDL(-) is present in plasma, its interaction with leucocytes, a cell type involved in atherosclerosis phenomena, is feasible; therefore, the aim of the current study was to evaluate LDL(-) effect on lymphocytes and monocytes isolated from human plasma.


RESULTS
Mononuclear cells were incubated with LDL(+) and LDL(-) and expression and release of several inflammatory mediators were analyzed by protein membrane assay, ELISA and real-time RT-PCR. LDL(-) induced a significantly increased production versus LDL(+) in MCP1, GRObeta, GROgamma, IL6, IL8 and IL10 in monocytes as well as in lymphocytes. These induced molecules are inflammatory, except for IL10 which is considered an anti-inflammatory cytokine. Therefore, the role of IL10 was evaluated in experiments where exogenous IL10 or antibodies anti-IL10 or anti-IL10 receptor were added. IL10 addition diminished the release of the other factors induced by LDL(-) near to basal production both at protein and RNA level. In contrast, the antibody anti-IL10 increased inflammatory cytokine release around two-fold, whereas the antibody anti-IL10 receptor produced a lower effect.


CONCLUSIONS
LDL(-) promoted inflammatory cytokine production in leucocytes; however, it also induced IL10 that minimized this effect. Therefore, IL10 developed a significant role in counteracting the LDL(-) inflammatory action.
Benítez
Sònia
S
Servei Bioquímica, Institut de Recerca, Hospital de la Santa Creu i Sant Pau, C/Antoni Maria Claret 167, 08025 Barcelona, Spain. sbenitez@hsp.santpau.es
Bancells
Cristina
C
Ordóñez-Llanos
Jordi
J
Sánchez-Quesada
Jose Luis
JL
D016207:Cytokines / Q000235:genetics; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000503:physiopathology* / Q000517:prevention & control; D016753:Interleukin-10 / Q000494:pharmacology* / Q000502:physiology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000502:physiology*; D008077:Lipoproteins, LDL / Q000097:blood* / Q000494:pharmacology*; D008214:Lymphocytes / Q000502:physiology; D009000:Monocytes / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D016207:Cytokines; D008077:Lipoproteins, LDL; D016753:Interleukin-10