The Eosinophil: Structure and Biochemical Composition

Gerald J. Gleich Allergic Diseases Research Laboratory, Departments of Medicine and Immunology, Mayo Medical School, Mayo Clinic, and Mayo Foundation, Rochester, Minnesota 55901

Search for other papers by Gerald J. Gleich in
Current site
Google Scholar
Restricted access

The eosinophil was first discovered in 1846 and ever since it has been an object of curiosity and fascination to investigators. The literature on eosinophils is vast; Schwarz's review done in 1913 contains 1,200 references. Nonetheless knowledge of the structure and of the chemical composition of the cell has continued to grow and in the past decade a series of studies have disclosed new information. In this review certain of the more recent reports dealing with the structure and biochemistry of the eosinophil will be discussed.

Cytoplasmic organelles of eosinophils The distinguishing feature of the eosinophil under the light microscope is the dense eosinophilic granulation which may completely fill the cytoplasm. When viewed under the electron microscope the eosinophil granule, as shown in Figure 1, is seen as a membrane bounded cytoplasmic organelle with a distinctive internal structure. In most cases, the eosinophil granule has an electron dense core and a less dense matrix.