Recently serial experimental studies on the transformations of reticular cells into plasma
cells were reported by co-workers in our department. They confirmed histologically the
transformation in the thymus from irradiated rats; in the spleen and lymph node from
adrenalectomized rats and treated with cortisone or DOCA; in the transplanted spleen;
and also autoradiographically in the spleen and the lymph node from the rats treated
with cortisone, DOCA or from adrenalectomized rats.
It is a well known fact that the plasma cell is most easily differentiated from the
lymphocyte by the characteristic feature that is richness of rER in the cytoplasm.
Thus the author applied electron microscopy to this study.
Materials find Methods
Albino male rats, weighing approximately 200 gms, were used. The transplantation of
the spleen were performed by the Cameron and de Saram method. The experimental
rats wer divided into 10 groups.
The transplanted spleen were histologically (H & E, methyl green pyronin, van Gisson)
and electron-microscopically observed.
Results
Within 3 days implanted spleen fragments became almost completely necrotic but
splenic capsule, tratecauae and reticular tissues were remained. The beginning of
regeneration usually started subcapsularly.
At the 4th day the invasion of newly formed capillary accompanied with fibrous tissue
appeared extracepsularly, and then appeared subcapsularly.
The regenerative cells appeared at first in the subcapsular reticular tissue and they
were characterized by round oval vesicular nuclei with abundant cytopiasm. These cells
were localized in the subcapsular area forming cell clusters and were strong1y
pyroninophilic and quite separated topographicaily from other leukocytes such as and
small lymphocytes, neutrophils which were found around capillaries.
These colonized cells had many mitochondria and rER in their cytoplasm, and were
strongly indicative of young plasma cells. Such colonization was numerous and, with
progress of regeneration, the same colonization of young plasma cells appeared in the
newly formed splenic cord. In parallel with progress of regeneration, most cells became
mature plasma cells.
The cells in the colonization showed electron-microscopically successive transitional
pattern from the reticular cells to young or mature plasma cells.
Conclusion
In the autotransplanted spleen, it was confirmed light and electron-microscopically that
the plasma cell arises from the reticular cell in the regenerative spleen.
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