CXCL8 and infection: This might be due to the fact that only sensor (cxcr4) and regulatory (cas1, cc1, and cxcl8) genes were significantly upregulated and not the effector genes hpc and dic, at least not at 18, 24, and 36 h p.i. Strangely, the administration of empty MPs also seemed to have some positive effect on survival following infection as at 120 h p.i., the survival rate in group C1 was significantly higher than in group C2 (no MP, infected).