Nitric oxide participates at the first steps of Apis mellifera cellular immune activation in response to non-self recognition

Abstract

The honey bee Apis mellifera (Hymenoptera) is being affected by many diseases. The elimination of organisms in the insect hemocoel requires hemocytes recognition and response to the invader. After recognizing a surface as “foreign,” hemocytes “spread.” Spreading on glass surfaces by insect hemocytes is used as a measure of immune activation. Nitric oxide (NO) is a signaling and immune effector molecule in response to microbial infection that has been proposed as a key molecule in invertebrate immunity. The participation of NO in the hemocytic response of A. mellifera upon recognition of non-self is herein analyzed. Glass-adherent hemocytes produce large amounts of NO. Treatment with NO donor sodium nitroprusside enhanced hemocyte spreading, while NO scavenger carboxyPTIO reduced hemocyte immune activation. These results are indicative of NO participation at the beginning of A. mellifera immune response to non-self.