Phenotypical heterogeneity of testicular macrophages/dendritic cells in normal adult mice: an immunohistochemical study.

The distribution of macrophage/dendritic cell antigens was investigated immunohistochemically in frozen testis sections of normal A/J mice using a panel of rat monoclonal antibodies against murine macrophage/dendritic cell antigens (F4/80, BM8, MP23, MOMA1, MOMA2, M5/114, BMDM1 and NLDC145). Sections of lymphoid organs were employed as positive controls. Stained-macrophages/dendritic cells in the testicular interstitium were various in shape, such as irregular-, elongate-, round- or oval-shaped cytoplasm with short or long cytoplasmic protrusions, but, the most conspicuous morphology was irregular. The testicular macrophages/dendritic cells were subdivided into four types of cells by their localization; various-shaped cells associated with Leydig cells and other interstitial cells (Type I); stretched cells attached to the seminiferous tubular wall (Type II); stretched cells attached to the blood vessel wall (Type III); and stretched cells attached to the inner side of the testicular capsule (Type IV). Examination of the staining pattern of the various antibodies showed that the macrophage/dendritic cell antigens differed from each other in amount present and localization, indicating phenotypical heterogeneity of the testicular macrophages. Additionally, a few macrophages were identified in the testicular capsule and in the tubuli recti but never in the seminiferous tubules.