C5AR1 and Sepsis: In contrast, a blockade of C5a by various strategies in sepsis models, e.g., by anti-C5a antibodies, C5aR antibodies, small peptide C5aR1 antagonists, C5a-neutralizing mirror-image (l-)aptamer C5a aptamers, was coherently protective against biochemical and histological evidence of MODS and in general improved survival of sepsis (53, 55–61).