The murine Kupffer cell. I. Characterization of the cell serving accessory function in antigen-specific T cell proliferation.

Murine Kupffer cells, the tissue macrophages of the liver, were isolated by collagenase digestion, differential sedimentation over Metrizamide, and glass adherence. The resultant cell population was more than 86% phagocytic, and 95% of cells stained positively for alpha-naphthyl butyrate esterase activity. The cells also had cell surface receptors for complement (C) and the Fc portion of IgG. In addition, a large proportion of Kupffer cells was shown to bear Ia antigens: about half of the cells bore I-A subregion-encoded antigens and about half bore I-BJE or I-EC subregion-encoded antigens. Kupffer cell populations were capable of reconstituting antigen-stimulated proliferative responses of antigen-primed, macrophage-depleted, lymph node T cells. The ability to reconstitute proliferation was enriched in the adherent population and was resistant to radiation and treatment with an anti-Thy antiserum and C. We conclude that isolated murine Kupffer cells bear the Ia phenotype of accessory cells that function in antigen presentation and that Kupffer cells can participate in the induction of antigen-specific immune responses. These data suggest that Kupffer cells may play a role in modulating responses to enterically derived antigens.     

The origin of the eukaryotic cell. III. Principles of the morphofunctional organization of the eukaryotic cell

The eukaryotic plasmalemma, eukaryotic cytoplasm with its usual cytomembranes, and eukaryotic nucleus are obligatory components of the eukaryotic cell. All other structural elements (organelles) are only derivates of the aforesaid cell components and they may be absent sometimes. There are protozoans having simultaneously no flagelles, mitochondria and chloroplasts (all the representatives of phylum Microspora, amoeba Pelomyxa palustris, and others). The following five general principles play the main role in the morphofunctional organization of the cell. The principle of hierarchy of block organization of living systems. Complex morphofunctional blocks (organelles) specific for the eukaryotic cell are formed. The compartmentalization principle. The main cell organelles (nuclei, flagellae, mitochondria, chloroplasts, etc.) undergo a relative morphological isolation from each other and other cell organelles by means of the total or partial surrounding by membranes; this may ensure the originality of their evolution and function. The principle of poly- and oligomerization of morphofunctional blocks. It permits the cell to enlarge its sizes and to raise the level of integration. The principle of heterochrony, including three subprinciples: conservatism of useful signs; a strong acceleration of evolutionary development of the separate blocks; simplification of the structure, reduction or total disappearance of some blocks. It explains a preservation of prokaryotic signs in the eukaryotic cell or in its organelles. The principle of independent origin of similar morphofunctional blocks in the process of evolution of living systems. The parallelism of the signs in unrelated groups of cells (or protists) arises due to this principle.     

The pathobiology of the human enterochromaffin-like cell.

The significance of the enterochromaffin-like (ECL) cell as a critical endocrine regulator of gastric fundic mucosal function has only recently been recognized. Although the percentage of these cells present in the human fundic mucosa is less than that in rodents, the observation that they secrete histamine and are probably important modulators of parietal cell function has resulted in their attaining some considerable biological significance. The further identification of gastrin and somatostatin receptors on the surface of the ECL cells has suggested that other neurohormonal influences may be significant in the regulation of parietal cell function, utilizing the ECL cell as an intermediate modifier. While abnormalities of ECL cells in the human stomach (hyperplasia/neoplasia) have been mostly confined to observations in patients with pernicious anemia and atrophic gastritis, the recent recognition of hyperplasia in pharmacotherapeutically induced achlorhydric or hypochlorhydric states has excited considerable interest. It has been proposed that the generation of luminal hypo- or achlorhydria by powerful acid inhibitory pharmacotherapy may result in hypergastrinemia. This condition is responsible initially for the development of hyperplasia and, subsequently, possibly even neoplasia of the ECL system of the fundic mucosa. This phenomenon seems to be prevalent in rodents but has so far been only rarely observed in humans, e.g., pernicious anemia, atrophic gastritis. In particular, patients with the gastrinoma component of the multiple endocrine neoplasia type I syndrome exhibit ECL-cell hyperplasia and neoplasia after exposure to acid inhibitory pharmacotherapy. It is therefore likely that an underlying genomic phenomenon is necessary prior to the induction of hyperplasia and subsequent neoplastic transformation. The scientific evaluation of the relationship between gastrin, ECL-cell function, and the development of hyperplasia and neoplasia may provide some important information in regard to the molecular evolution of gastrointestinal neuroendocrine disease states. It is possible that the future pharmacotherapy of acid secretory disease may require regulation not only of parietal cell but of ECL-cell function.     

The initiation of mast cell degranulation: activation at the cell membrane.

The low molecular weight mast cell activator, polymyxin B, has been covalently bound to an insoluble matrix of Sepharose 4B. It has been demonstrated that mast cells in preparations of rat peritoneal cells bind to Sepharose 4B-polymyxin B beads but not to control beads. The bound cells are stimulated to degranulate by this interaction at the cell membrane with the resultant release of biogenic amines.     

The laws of cell energetics.

Recent progress in membrane bioenergetics studies has resulted in the important discovery that Na+ can effectively substitute for H+ as the energy coupling ion. This means that living cells can possess three convertible energy currencies, i.e. ATP, protonic and sodium potentials. Analysis of interrelations of these components in various types of living cells allows bioenergetic laws of universal applicability to be inferred.