Larval Lymph Gland Dissection: Isolating the Drosophila Hemocyte-Producing Organ

- The Drosophila melanogaster larval lymph gland is responsible for the production of hemocytes, or blood cells, that circulate in the larval hemolymph. To identify the lymph gland, first find the dorsal vessel, or heart, which pumps hemolymph throughout the body. Follow the dorsal vessel towards the head until you find the brain. The lymph gland is a small, multi-lobed structure next to the brain, flanking the dorsal vessel.

To find the primary lobe, identify the largest lobe of the gland. This lobe contains three zones, defined by different stages of hemocyte development. The medullary zone closest to the dorsal vessel contains immature hemocyte, while the cortical zone contains mature hemocytes. At the posterior end of the primary lobe, you can find the posterior signaling center, composed of specialized hemocytes. The secondary and tertiary lobes are smaller and do not have defined zones.

To dissect the lymph gland, you will need a dissecting microscope, two forceps to manipulate the larvae, and a buffered saline solution.

In this example, we will dissect lymph glands for use in immunohistochemistry.

- To begin lymph gland dissection, add 1 milliliter of 1x PBS to 1 well of a 2