Multinucleate parietal cells and cytoplasmic inclusion bodies in the gastric epithelium of callitrichids

Abstract

Inclusion bodies (IBs) and multinucleate cells can be associated with viral infections; however, IBs and multinucleate cells have been described in normal tissue and with non-viral disease processes in multiple species. We examined fundic stomach from 50 callitrichids histologically for bi- and multinucleate parietal cells and cytoplasmic IBs in gastric epithelial cells. Callitrichids represented included 6 genera: Saguinus (4 spp.), Leontopithecus (1 sp.), Mico (3 spp.), Cebuella (1 sp.), Callithrix (1 sp.), Callimico (1 sp.), and 13 unspecified marmosets. Gastric epithelial IBs were present in 46 of 47 (98%) of the callitrichids from which the stomach was sufficiently well preserved to identify IBs. Cytoplasmic IBs were identified in gastric surface pit epithelial cells (43 of 44, 98%), mucous neck cells (43 of 44, 98%), parietal cells (43 of 44, 98%), and chief cells (43 of 44, 98%). The IBs were eosinophilic, ovoid, round, elongate, or variably indented, sometimes slightly refractile, and 1-6 × 1-13 µm. IBs were sometimes perinuclear and molded around the nucleus. Electron microscopy of the gastric epithelium of one marmoset indicated that IBs were composed of intermediate filaments. The IBs did not stain with immunohistochemical markers for cytokeratin AE1/AE3 or vimentin. Binucleate parietal cells were found in 49 of 50 (98%) callitrichids, and multinucleate parietal cells were observed in 40 of 49 (82%) callitrichids. Gastric epithelial cytoplasmic IBs and bi- and multinucleate parietal cells are likely a normal finding in callitrichids, and, to our knowledge, have not been reported previously.

Keywords: Callitrichidae; gastric mucosa; inclusion bodies; multinucleation.

Figures 1–6.

Gastric fundic mucosa of callitrichids. H&E. Figure 1. Frequent, variably sized and shaped eosinophilic cytoplasmic inclusion bodies (IBs) in gastric surface pit epithelial cells in a cotton-top tamarin (Saguinus oedipus). IBs are often perinuclear and sometimes exhibit nuclear molding. Figure 2. Eosinophilic cytoplasmic IBs are present in all mucosal epithelial cell types in a cotton-top tamarin. Figure 3. A low number of eosinophilic cytoplasmic IBs are present, predominantly in mucous neck cells, in a marmoset (species unknown). Figure 4. Variably sized and shaped eosinophilic IBs are present in parietal cells and few chief cells in a cotton-top tamarin. A few cells contain multiple IBs. Figure 5. A moderate number of eosinophilic cytoplasmic IBs, predominantly within chief cells, in a marmoset (species unknown). Figure 6. Bi- and multinucleate parietal cells, gastric fundic mucosa in a pygmy marmoset (Cebuella pygmaea). Multiple bi- and multinucleate parietal cells are present, often exhibiting prominent cytomegaly compared to surrounding uninucleate parietal cells.

Figure 7.

Transmission electron micrograph of an epithelial cell in marmoset (species unknown) gastric mucosa with an ovoid perinuclear, unencapsulated, intracytoplasmic inclusion body composed of a tangle of filaments. Bar = 600 nm. Inset: filaments are 10–17 nm diameter and have faint regular banding. Bar = 100 nm.