Electron Microscopic Observations of Epithelioid Cell Granulomas Experimentally Induced by Prototheca in the Skin of Mice

Abstract

Electron microscopic analysis was conducted on epithelioid cell granulomas experimentally induced by prototheca in the skin of mice. In BALB/c mice, epithelioid cell granulomas were easily induced. Each cell had a round nucleus with euchromatin on the margin, abundant cytoplasmic organelles, and particularly abundant rough endoplasmic reticulum (rER). Cells with a plasmacytoid appearance were the most common. Fibroblast-like epithelioid cells were sometimes observed. The whole body and cell membrane of an organism was usually within the cytoplasm of epithelioid cell. In ICR mice, epithelioid cell granulomas were not easily induced. Cells which had ingested whole organisms had spindle shaped and/or oval nuclei with marginated heterochromatin and with abundant dilated rER. Near completion of organism digestion, the cells had irregular and/or indented nuclei with marginated heterochromatin and often one or two distinct nucleoli. The cytoplasm was often replaced with numerous phagocytic vacuoles. At higher magnification, secondary lysosomes and Golgi complexes forming Golgi lamellae could be seen in the cells in which cytoplasmic organelles such as endoplasmic organelles and mitochondria were abundantly present. In contrast to the BALB/c mice, the remnants of digested organisms, split up into many small pieces, could be seen in the cytoplasm. The cells with a fibroblast-like appearance were most frequent, but plasmacytoid cells were sometimes observed. In the present study, the ultrastructural features of epithelioid cells in BALB/c and ICR mice clearly differed. Plasmacytoid cells were the most abundant in BALB/c mice, while fibroblast-like cells were in ICR mice.

Prototheca zopfii Induced Ultrastructural Features Associated with Apoptosis in Bovine Mammary Epithelial Cells

“…In an experimental infection of Prototheca in the BALB/c mice demonstrated that cells with whole organism have spindle shaped and/or oval nuclei with abundant dilated rough endoplasmic reticulum. Cells near the completion of pathogen digestion, presented irregular and/or independent nuclei with often one or two distinct nucleoli and also the cytoplasm was often replaced by phagocytic vacuoles (Horiuchi and Masuzawa, 1995). Electron microscopy of mammary gland from cows infected with P. zopfii elaborated that the macrophages with algae were distinctly enlarged due to primarily from reduplication of the Golgi complexes and its associated vesicles.…”

Epithelioid Cell: A New Opinion on Its Nature, Parentage, Histogenesis, Cytomorphogenesis, Morphofunctional Potency, Role in Pathogenesis and Morphogenesis of Tuberculous Process

“…The majority of investigators registered that ECs have lower phagocytic activity in comparison with Mphs. In cytoplasm of ECs the lipids, which are surveyed as oddments of the killed and digested micro-organisms, also crystalloid frames, asteroid bodies, formation such as phagosomas and multivesicular bodies, are detected (Horiuchi & Masuzawa, 1995;Navarro et al, 1992). It is necessary to underline that there are contradictory enough data about ability of ECs to phagocytic response.…”

“…The cell-like center in the majority of ECs more volumetric that than in mature Mphs is marked. Thus, ascending density of filaments in cytoplasm, which have radial orientation and diameter 5-6 nm or about 10 nm is revealed (Epstein, 1991;Horiuchi & Masuzawa, 1995;Turk, 1989). Under the data Rhee (1979) secondary lysosomes and macrophage granula in such cells are not taped.…”

“…Thus, the accumulation ECs in the center of granulomatous inflammation is reduced to stochastic (on probability of an induction) and continuous transformation Mphs into ECs (Haley et al, 1994;Okabe, 1994). Three types of ECs are now defined: plasmacyte-like, vesicula-like and fibroblast-like (Epstein, 1991;Horiuchi & Masuzawa, 1995;Rasmussen & Petersen, 1993). Т.…”