Other immune factors that were identified but did not appear to be regulated by infection include a Gram-negative bacteria binding protein [GI:110755978], peptidoglycan recognition protein (PGRP) SA [GI:110765019] and PGRP SC2 [GI:66522804], suggesting that the response seen for lysozyme and hymenoptaecin is a specific response to P. larvae infection. Here, PGLYRP1 is linked to infection.