Hemocyte response to cell injury in the tobacco hornworm, Manduca sexta

Many hemocytic immune reactions require chemotaxis to properly function. However, the exact mechanism of hemocyte recruitment and chemotaxis has yet to be elucidated. These questions are addressed: (1) Will hemocytes, when injured, elicit a chemoattractive response from healthy hemocytes? (2) Will selected tissues, when injured, elicit a chemoattractive response from healthy hemocytes? This study hypothesized that injured tissues, including hemocytes, will elicit a chemoattractive response from healthy hemocytes. This hypothesis was tested using the Boyden chamber assay. Selected injured tissues and hemocytes from the tobacco hornworm, Manduca sexta, were tested for their ability to evoke a chemoattractive response from healthy hemocytes. Results indicated that injured hemocytes, fat body, cuticle, and silk gland elicit a percent migration that was statistically greater than that of the negative control (dPBS), which indicates that hemocytes are moving towards these injured tissues at a rate that is greater than that of background cell movement. Injured gut and malpighian tubules do not. Outcomes from these investigations contribute to our understanding of insect cellular immune responses.