S-100 alpha-like immunoreactivity in tubules of rat kidney. A clue to the function of a "brain-specific" protein

The localization of the alpha and beta subunits of S-100 protein was studied in normal tissue where the identification of three subclasses of S-100 containing cells was derived: i) cells that contain both alpha and beta subunits; ii) cells that contain only the alpha subunit; and iii) cells that contain only the beta subunit. In this study monospecific antibodies against the S-100 alpha and beta subunits were used to characterize the S-100-like immunoreactivity in the rat kidney: Certain cells in the distal nephron, i.e., the connecting piece, collecting ducts, and the thin limb of Henle's loop, contained S-100 alpha immunoreactivity. Proximal tubules, the thick ascending limb of Henle's loop, the distal tubules, and the juxtaglomerular apparatus were negative. No S-100 beta immunoreactivity was found in kidney tubules. However, Schwann cells of renal pelvic nerves contained S-100 beta immunoreactivity. The presence of S-100 alpha antigen in certain cells of the kidney gives further support to the assumption that the alpha subunit of S-100a is related to cells that are highly involved in pH, electrolyte, and water regulation.     

S-100-like immunoreactivity in a planarian

Summary The presence of an S-100-like immunoreactivity was investigated in the planarian Dugesia gonocephala. By microcomplement fixation assay, measurable amounts of S-100-like immunoreactive material (0.11g/mg soluble protein) were detected in planarian high-speed supernatants. The index of immunological dissimilarity between ox S-100 and planarian S-100-like immunoreactive material was higher than that previously calculated between ox S-100 and all the vertebrates tested. By the immunohistochemical PAP method, S-100-like immunoreactivity was only detectable in the cilia of the epidermal cells. Although the biological meaning of S-100-like immunoreactivity in planarian remains to be clarified, the present data introduce new perspectives into the investigation of S-100.     

Differential distribution of immunoreactive S-100 protein in mammalian testis

The present study deals with the immunohistochemical localization of S-100 protein in the testes of seven mammalian species including rat, cat, dog, pig, sheep, cattle and horse. Significant differences are demonstrated in the cellular distribution and intensity of immunoreaction for the protein. In bull, ram, boar and cat tests S-100 protein was localized in the cytoplasm and nuclei of Sertoli cells. A particularly intense staining was seen in the modified Sertoli cells of the terminal tubular segment. With the exception of the cat and horse S-100 protein immunoreactivity was additionally found in epithelial cells of the straight testicular tubules and in the epithelial cells of the rete testis. Endothelial cells of capillaries, veins and lymphatic vessels are regularly S-100 immunoreactive in ruminants. Leydig cells were found to be strongly positive for S-100 protein in the cat and rat testes and to a lower degree in pig and horse testes. Finally a distinct immunostaining of peritubular cells was restricted to the testis of dogs and rats. The remarkable species-specific variations of immunoreactivity for S-100 protein in different cell types of the testis support the hypothesis that S-100 protein is a multifunctional protein and may have a different function in testicular physiology.     

Immunohistochemical demonstration of S-100 protein in epithelial cells of bovine oviduct

The present study deals with an immunohistochemical localization of S-100 protein in the bovine oviduct. The epithelium of the infundibulum, ampulla and isthmus showed a positive staining for S-100 protein. The immunoreactivity for S-100 was observed both in the ciliated and nonciliated (secretory) cells of the oviductal epithelium at any stages of the estrous cycle. The immunoreactivity was also found in nervous elements and endothelial cells of blood vessels. No cell outside these cells showed any immunoreactivity for S-100. Although the functional significance of S-100 protein in the oviductal epithelium remains to be elucidated, the present results introduce new perspectives into the investigation of function and localization of S-100 protein.     

Immunohistochemical co-localization of glycogen phosphorylase with the astroglial markers glial fibrillary acidic protein and S-100 protein in rat brain sections.

Immunofluorescence double-labelling and immunoenzyme double-staining methods were used to examine the location of glycogen phosphorylase brain isozyme with the astrocyte markers glial fibrillary acidic protein (GFAP) and S-100 protein in formaldehyde-fixed, paraffin-embedded slices from adult rat brain. Astrocytes in the cerebellum and the hippocampus, which express GFAP or S-100 protein immunoreactivity, show glycogen phosphorylase immunoreactivity. Regional intensity and intracellular distribution of the three antigens vary characteristically. In ependymal cells, glycogen phosphorylase immunoreactivity is co-localized with S-100 protein immunoreactivity, but not with GFAP immunoreactivity. These findings confirm that glycogen phosphorylase in the rat brain is exclusively localized in astrocytes and ependymal cells. All astrocytes, as far as they express GFAP or S-100 protein, do contain glycogen phosphorylase.     

Immunohistochemical co-localization of glycogen phosphorylase with the astroglial markers glial fibrillary acidic protein and S-100 protein in rat brain sections

Summary Immunofluorescence double-labelling and immunoenzyme double-staining methods were used to examine the location of glycogen phosphorylase brain isozyme with the astrocyte markers glial fibrillary acidic protein (GFAP) and S-100 protein in formaldehydefixed, paraffin-embedded slices from adult rat brain. Astrocytes in the cerebellum and the hippocampus, which express GFAP or S-100 protein immunoreactivity, show glycogen phosphorylase immunoreactivity. Regional intensity and intracellular distribution of the three antigens vary characteristically. In ependymal cells, glycogen phosphorylase immunoreactivity is co-localized with S-100 protein immunoreactivity, but not with GFAP immunoreactivity. These findings confirm that glycogen phosphorylase in the rat brain is exclusively localized in astrocytes and ependymal cells. All astrocytes, as far as they express GFAP or S-100 protein, do contain glycogen phosphorylase.     

Immunohistochemical localization of S-100 protein subunits (alpha and beta) in dorsal root ganglia of the rat

The distribution of S-100 protein and their subunits (alpha and beta) in lumbar dorsal root ganglia of adult rat was investigated immunohistochemically using monoclonal antibodies against the S-100 protein, alpha-subunit and beta-subunit of S-100 protein. The conventional S-100 protein antibody stained both neurons (large and intermediate in size; 20.3% and 41 +/- 3.2 microns of diameter) and glial cells (satellite cells and Schwann cells). The immunoreaction for the alpha-subunit was observed in the perikarya of some large and intermediate sized neurons (17.2%, 45.6 +/- 6.1 microns of diameter), satellite cells and Schwann cells, whereas the beta-subunit immunoreactivity was found principally in glial cells, and in a scarce number of large and intermediate sized neurons (2.8%, 43.3 +/- 5 microns of diameter) Our results demonstrate that a subpopulation of large and intermediate sized neurons of lumbar DRG contain alpha- and beta-subunits of S-100 protein, being alpha-subunit predominant. Furthermore, the satellite glial and Schwann cells contain also the two subunits but mainly beta-subunit. These data confirm previous studies about the presence of S-100 protein in neurons of the central and peripheral nervous system.     

Measurement and localization of angiotensin-like immunoreactivity in juxtaglomerular cells of the rat

The existence and distribution of angiotensin I (A I) and angiotensin II (A II) in rat kidney were examined in immunocytochemical studies using the peroxidase-antiperoxidase technique and in biochemical studies using rat kidney homogenates extracted with acid-ethanol and purified by Sephadex G-25 gel chromatography. Immunopositive A II-like staining was observed in the juxtaglomerular cells of the afferent arteriole, but no histochemical evidence for A I was found. On the other hand, renal homogenates were found to contain both A I and A II immunoreactivities which coeluted on gel chromatography with synthetic A I and A II. These results indicate that A I as well as A II immunoreactivities are present in the kidney and that A II immunoreactivity can be localized to the juxtaglomerular cells. The origin of the immunoreactive A II in the juxtaglomerular cells remains to be determined.     

Differential localization of "brain-specific" S-100 and its subunits in rat salivary glands

In the rat, the S-100 antigens in the submandibular gland were found to be immunochemically identical with those in the brain (glial cells) when compared using crossed immunoelectrophoresis. Specific antibodies against the S-100a non-beta and against the S-100 beta subunit were prepared from antibodies against crude S-100 protein and from S-100 components (S-100a and b) by affinity chromatography. In the rat salivary glands a differential distribution of subunit immunoreactivity was clearly evidenced using indirect immunofluorescence. Certain intercalated duct cells of the submandibular gland as well as Schwann cells contained the S-100 beta subunit immunoreactivity exclusively, while other duct cells in parotid, submandibular, and sublingual glands contained S-100a non-beta subunit immunoreactivity. Both subunits were present in astrocytes and ependymal cells. The immunocytochemical localization of alpha and beta subunits is a promising technique for the classification of various types of S-100-containing cells.     

Immunocytochemical evidence for the presence of S-100 protein in insulin-containing cells of cultured fetal rat islets

S-100 protein was long considered to be specific to glial and Schwann cells, but was subsequently proved to be present in various organs. In particular, S-100 proteinimmunoreactivity was demonstrated in the parathyroid gland, adenohypophysis and endocrine pancreas. In the present study cultured fetal rat islets were investigated in view of the possible presence of S-100 protein immunoreactivity in their cells. In the initial 5-day period, continuity between islets and ducts could be demonstrated, and the islets appeared to bud from the ducts. During this time, S-100 protein-immunoreactive cells were found in either the budding islets or ducts. The colocalization of S-100 protein and insulin was demonstrated immunocytochemically. In contrast, the newly formed islets from endocrine monolayers did not display S-100 protein immunoreactivity. After this initial period, numerous free-floating islets were observed, but only some of them contained S-100 protein immunoreactivity. S-100 protein-immunoreactive cells had the same distribution as those storing insulin, again suggesting the coexistence of the two peptides. The results suggest that S-100 protein might be involved in the regulation of islet function.     

Distribution of S-100 protein and its subunits in bovine exocrine glands

 The distribution of S-100 protein and its α- and β-subunits in bovine exocrine glands was studied by indirect immunohistochemistry. The entire spectrum of salivary glands, glands of the respiratory tract, intestinal glands, male and female genital glands, and skin glands was examined. S-100 and its β-subunit were identified in most serous secretory cells of mixed salivary glands, although secretory acini in some serous glands remained unreactive for these antigens. Mucous cells were constantly negative; mucoid cells were positive in the lacrimal and Harderian gland. The α-subunit of S-100 protein was identified in serous cells but the staining reaction was faint. Subunits of S-100 showed a characteristic distribution along the excretory duct systems of compound glands: S-100 and the β-subunit were present in intercalated duct epithelium, while striated duct epithelium stained for S100-α. Therefore, it is suggested that S100-α is related to resorption and secretion in striated ducts, while S100-β may govern acinar exocytosis and probably regulates proliferation and differentiation of glandular cells. Differing staining intensities for S-100 and its subunits in secretory cells of exocrine glands most probably indicate functional differences with regard to secretory activity and the cell cycle. Accepted: 11 February 1997     

Fate of degenerating lactotrophs in rat pituitary gland after interruption of lactation: a histochemical and immunocytochemical study

Summary In the pituitary gland of pregnant and lactating rats a striking proliferation of lactotrophs occurs to meet the increased demands for prolactin. Following interruption of lactation the redundant lactotrophs undergo a massive degeneration until pre-pregnant proportions are re-established. Immunocytochemical detection of prolactin allows the recognition of degenerating lactotrophs until advanced stages of degeneration and leads to the conclusion that this process is autolytic in nature. Histochemistry of acid phosphatase reveals a remarkable accumulation of this enzyme in Golgi cisternae and lysosomes. At later stages of degeneration the acid phosphatase spreads throughout the entire cell. The presence of increased numbers of necrotic cells appears to activate phagocytosis of stellate cells and, to a lesser extent, of follicular cells. Stellate cells responsible for the secondary processing of cell residues are isolated cells characterized by a prominent oval nucleus and an electron-lucent cytoplasm with scarce organelles and extensive cytoplasmic processes. They appear as scavenger cells engulfing cell remnants and debris. Immunocytochemistry of S-100 protein discloses differential staining of two types of cell, one forming clusters of 2–4 cells with faint immunoreactivity, while the other type consists of isolated cells with a stellate profile and stronger labelling to S-100 protein.     

Immunohistochemical studies of S-100 protein alpha and beta subunits in adenoid cystic carcinoma of salivary glands

Immunohistochemical studies were performed to explore the distribution of S-100 protein and its alpha, beta subunits in 76 adenoid cystic carcinomas (ACC) of the salivary glands. Histopathologically. ACC was divided into cribriform, tubular, basaloid and trabecular types which could be mixed in the same tumor. S-100 protein was usually positive in tumor cells forming cribriform structures; foci of strongly positive tumor cells were also distributed in the luminal layer of tubular structures, and in areas transitional between cribriform and tubular patterns. S-100 alpha staining was confined to some tumor cells in cribriform areas, to luminal tumor cells in tubular structures and to few tumor cells in basaloid structures. S-100 beta reaction was usually localized to luminal surfaces in a fine granular pattern in tubular and microtubular structures in a distribution somewhat similar to that in the normal salivary gland. Great heterogeneity in the immunohistochemical distribution of S-100, S-100 alpha and S-100 beta proteins was found in the various histologic types of ACC and the pattern was different from that seen in pleomorphic adenomas. It is possible that the ACC tumor cells positive for S-100 protein may be closely related to true or modified myoepithelial cells.     

Identification of cell types containing S-100b protein-like immunoreactivity in the islets of Langerhans of the guinea pig pancreas with light and electron microscopy

Summary Cell types containing S-100b protein-like immunoreactivity in the islets of Langerhans of the guinea pig were studied by light- and electron-microscopic immunocytochemistry using antisera to S-100b protein, insulin, glicentin, somatostatin, and pancreatic polypeptide. Two types of S-100b-immunoreactive cells were identified. The first type was stellate and characterized by thin cytoplasmic processes sheathing endocrine-type cells, especially pancreatic A-cells. It was located predominantly in the neuro-insular complex and in large islets, both of which were located near the main pancreatic duct. Intense immunoreactivity was found in the cytoplasmic matrix as well as in the nucleoplasm. Nerve fibers or endings were occasionally ensheathed by its cytoplasmic processes. The second type, whose immunoreactivity was rather weak and varied from one cell to another, was oval to polygonal in shape and located randomly throughout the islets. It was an endocrine cell-type and its immunoreactivity was located in the secretory granule. With the use of immunostained consecutive sections for demonstrating pancreatic endocrine cell-types, it was found that a portion of the pancreatic B-cell population expressed S-100b-like immunoreactivity.     

Distribution and ultrastructure of S-100-immunoreactive cells in the human thymus

Summary The present study deals with the localization and ultrastructure of S-100-immunoreactive cells in the human thymus. These immunoreactive cells are distributed mainly in the medulla with some scattered elements in the cortex. Electron-microscopic observation revealed that the cells are characterized by an irregularly shaped nucleus, tubulovesicular structures in the cytoplasm and characteristic interdigitations of the plasma membrane. The cells often embrace lymphocytes with their branched processes. On the basis of these morphological features, the immunostained elements were identified as interdigitating cells (IDCs). The immunocytochemistry for S-100 visualizes the precise distribution and extension of the IDCs under the light microscope and indicates that the IDCs form no structural networks such as those established by the thymic epithelial cells. Since the IDCs in human lymph nodes have also been reported to contain S-100-like immunoreactivity, S-100 protein can be regarded as a useful marker for identifying the IDCs in the human thymus and other lymphoid organs.     

Immunocytochemical localization of S-100 protein in astrocytes and Müller cells in the rabbit retina

Summary The localization of S-100 protein was studied in histological sections of retinae from adult rabbits. By use of double-immunolabeling techniques it was shown that most but not all radially oriented vimentin-positive Müller cells were co-labeled by an antiserum to S-100 protein. Glial fibrillary acidic protein-positive astrocytes, which in the rabbit retina are restricted to the medullary rays formed by myelinated optic nerve fibers, consistently showed S-100 protein immunoreactivity. The present report shows that, with respect to S-100 protein staining, Müller cells represent a heterogeneous population of glial elements.     

S-100 protein in the testis

Summary S-100, a protein originally believed to be unique to the nervous system, has recently been found in extraneural cell types. We report here on the presence of S-100 in the testis, namely in Leydig cells and in lymphatic endothelial cells, using immunohistochemical and immunochemical methods. We show that the protein in the testis is immunologically identical to brain S-100. The S-100-labelled cells in the testis exhibit morphological similarities with other cell types in different tissues known to contain S-100.     

Immunohistochemical studies of S-100 protein α and β subunits in adenoid cystic carcinoma of salivary glands

Immunohistochemical studies were performed to explore the distribution of S-100 protein and its α,β subunits in 76 adenoid cystic carcinomas (ACC) of the salivary glands. Histopathologically, ACC was divided into cribriform, tubular, basaloid and trabecular types which could be mixed in the same tumor. S-100 protein was usually positive in tumor cells forming cribriform structures; foci of strongly positive tumor cells were also distributed in the luminal layer of tubular structures, and in areas transitional between cribriform and tubular patterns. S-100 α staining was confined to some tumor cells in cribriform areas, to luminal tumor cells in tubular structures and to few tumor cells in basaloid structures. S-100β reaction was usually localized to luminal surfaces in a fine granular pattern in tubular and microtubular structures in a distribution somewhat similar to that in the normal salivary gland. Great heterogeneity in the immunohistochemical distribution of S-100, S-100 a and S-100β proteins was found in the various histologic types of ACC and the pattern was different from that seen in pleomorphic adenomas. It is possible that the ACC tumor cells positive for S-100 protein may be closely related to true or modified myoepithelial cells.     

Immunohistochemical study on the distribution of alpha and beta subunits of S-100 protein in human neoplasm and normal tissues

The immunohistochemical distribution and localization of the alpha and beta subunits of S-100 protein in human neoplasms and normal tissues were studied by the PAP method using monospecific rabbit antibodies against each subunit. Beta subunit immunoreactivity was detected in all S-100-positive cells and tumors reported previously. In contrast alpha subunit immunoreactivity was absent from Schwann cells, schwannomas, neurofibromas, granular cell myoblastomas, pituicytes of the neurohypophysis, Langerhans cells, interdigitating reticulum cells, and histiocytosis X cells. Interestingly, only the alpha subunit was detected in neurons of both central and peripheral nervous system, and in lymph node macrophages. Human S-100-positive cells are divided into three groups; the first is composed of cells containing only the beta subunit (probably S-100b; beta beta), the second consists of cells containing both the alpha and beta subunits, and the third is composed of cells containing only the alpha subunit (probably S- 100ao ; alpha alpha). The ontogentic relationships between S-100-positive cells and tumors are discussed in the light of these findings.     

Cytomorphology of Metastatic Melanoma—Use of S-100 Protein In the Diagnosis of Amelanotic Melanoma

The cytomorphological features of cells from 52 cases of metastatic melanoma obtained by fine needle aspiration cytodiagnosis were studied. Morphologically, 11, 19 and 22 cases were classified as spindle, epithelial, and mixed cell types of metastatic melanoma respectively. There were 34 melanotic and 18 amelanotic melanomas. Besides melanin, the presence of intranuclear cytoplasmic inclusions, eosinophilic macronucleoli and giant cells were helpful in the diagnosis of a melanoma. Where attempted, staining for S-100 protein was positive in all the 19 cases (eight amelanotic and 11 sparsely pigmented melanomas). In addition eight cases of metastatic tumour where a differential diagnosis of poorly differentiated carcinoma or large cell lymphoma was entertained, were also studied for localization of S-100 protein and all were found to be negative. Electron microscopy was performed in five cases and showed the presence of melanosomes and/or premelanosomes.