PGLYRP1 and infection: Additionally, the three members of the PGRP-SC locus negatively regulate the pathway in systemic mode [137] and triple pirk;PGRP-SC;PGRP-LB mutants (where the whole PGRP-SC locus has been deleted) showed low viability and a level of AMPs that was 8 times higher at 24 h post infection compared with wild-type flies [137].