Journal of the Reticuloendothelial Society最新文献

A nonlethal dose of Staphylococcus aureus was inoculated into the mainstem bronchus of mice in order to study the influx of polymorphonuclear leukocytes (PMN). The goal was to determine the routes of entry of PMN into the lung following bacterial challenge, the relative importance of PMN as compared to alveolar macrophages (AM) in the uptake of S aureus, and the role of lymphatics in clearance of intact microorganisms. Resident AM took up S aureus within minutes of inoculation, but PMN were subsequently recruited to the lung and were the predominant cell containing S aureus by 4 hours following inoculation. PMN were recruited from arteries, capillaries, and venules. Emigration of PMN into alveolar spaces occurred between type I epithelial cells as well as between type I and type II epithelial cells. Lymphatics played only a minor role in the clearance of S aureus.

Monocytes and macrophages from a variety of animal species produce procoagulants upon stimulation with endotoxin in vitro. While C3H/HeJ mice and their cells have exhibited refractoriness to known effects of phenol-water extracted endotoxin, two recent reports indicate that the cells of these mice produce procoagulants in a normal manner in response to endotoxin. This study compares the responsiveness of cells of C3H/HeJ and C3H/HeN mice to phenol-water extracted endotoxin and to disrupted gram-negative cell walls. Phenol-water extracted endotoxin had no mitogenic effect on spleen cells and failed to elicit procoagulant synthesis in exudate macrophages from C3H/HeJ mice. In contrast it was an effective stimulant for spleen cells and exudate macrophages of C3H/HeN mice. Gram-negative cell walls were an effective stimulant for spleen cells and macrophages from both mouse strains. I conclude that exudate macrophages of C3H/HeJ mice do not respond to endotoxin by producing procoagulant.

The role of toxic oxygen species in monocyte-mediated ADCC against the myelogenous cell line K-562 was investigated. Freshly isolated human monocytes caused 40% specific lysis of antibody-coated K-562 cells (Ab-K-562). Monocytes challenged with Ab-K-562 gave a small but definite luminol-dependent chemiluminescence response, indicating that a respiratory burst with generation of toxic oxygen species had been elicited. Generation of hydrogen peroxide in areas of close apposition between the monocyte and the Ab-K-562 plasma membranes was demonstrated by electron microscopy using precipitation of cerium ions as a cytochemical stain for hydrogen peroxide. Catalase inhibited the formation of cerium precipitates in the interaction zone between monocytes and Ab-K-562 cells. Despite evidence that toxic oxygen species were generated, the monocytes' cytolytic activity against Ab-K-562 was not inhibited by superoxide dismutase, catalase, or azide. Enzymatically generated fluxes of superoxide anion or hydrogen peroxide were not cytolytic to K-562 cells but did have a cytostatic effect. We conclude that toxic oxygen species are generated when human monocytes are challenged with Ab-K-562. However, these toxic oxygen species do not appear to be the major mediators of the monocytes' cytolytic activity in this experimental system.

This study examines the ultrastructure of mouse defective marrow stroma when cultured as a three-dimensional organization of cells. Gelfoam sponges impregnated with agar medium allowed the three-dimensional organization of newly formed stromal cells derived from the crevices of marrow-depleted bones of Steel mutant mice (Sl/Sld) with defective stroma and also from mice with normal stroma (Sl +/+, W/Wv, and W +/+. Ultrastructural comparisons of 5- to 14-day cultures revealed that the mutant defective stromal cells developed normally, viz. i) proliferated and formed a three-dimensional organization of stroma, ii) stimulated residual hemopoietic precursors to form myeloid cells, and iii) formed a variety of stromal cell types characterized by variable quantities of Golgi bodies and ER, glycogen, filaments, and round cytoplasmic granules. The Steel-Dickie strain, however, included bacilliform electron-dense granules in both normal and mutant stroma. The only ultrastructural deficiency in Sl/Sld stroma was the absence of a category of "activated" cells that occurred within normal cell populations.

Insolubilized lipopolysaccharides (LPS) were prepared by covalently coupling LPS from polysaccharide-deficient S. minnesota R595 and polysaccharide-rich E. coli 055:B5 to carboxylated latex particles. The stability of these LPS-latex complexes was determined using several assays to detect soluble LPS following incubation at ambient and elevated temperatures. Resident and thioglycollate-elicited macrophages from both LPS-responder C3HeB/FeJ and LPS nonresponder C3H/HeJ mice were examined for their capacity to phagocytose the LPS particles following in vitro culture for various time periods. Uptake was demonstrated by an increase in the number of particles within the macrophages with increasing time of incubation. Rough polysaccharide-deficient LPS-latex particles were found to be more readily phagocytosed than control particles, whereas smooth polysaccharide-rich LPS particles were phagocytosed less readily than the controls. Qualitatively similar results were found in the relative rate of uptake of particles by the macrophages from the endotoxin-responsive and -unresponsive mouse strains used in this study.

These studies demonstrate that the natural cytotoxicity of BALB/c mouse spleen cells for 51Cr-labeled YAC-1 cells can be significantly enhanced by microorganisms in the alimentary tract. Spleen cells from germfree BALB/c mice, euthymic, athymic, or non-nude background (+/+), had natural cell-mediated cytotoxicity for YAC-1 cells. Intestinal colonization with a few (flora-defined) or many (complex flora-conventionalized) microorganisms significantly enhanced natural cell-mediated cytotoxicity of athymic and euthymic mice over their germfree counterparts. Conversely, colonization of the alimentary tract of athymic and euthymic germfree mice with a pure culture of Candida albicans or colonization with Candida and a Bacillus sp. did not enhance natural cell-mediated cytotoxic activity over germfree levels. Spleen cells from germfree athymic mice were significantly more cytotoxic than spleen cells from germfree BALB/c mice that did not carry the nude gene (ie, +/+). In the germfree or gnotobiotic state, no difference in natural killer cell activity was evident between athymic (nu/nu) and heterozygous (+/nu) littermate mice; however, athymic (nu/nu) flora-defined or conventionalized mouse spleen cells were significantly more cytotoxic for YAC-1 cells than splenocytes from flora-defined or conventionalized heterozygous (+/nu) littermates. Spleen cells from BALB/c mice that were athymic (nu/nu) and colonized with a complex microbial flora (ie, conventionalized) had the highest percentage of cytotoxicity, at three different effector to target ratios, for YAC-1 cells. These studies indicate that the intestinal microflora can alter murine natural cell-mediated cytotoxicity.

Pure cultures of murine bone marrow-derived macrophages produce interferon (IFN) after exposure to endotoxin. The levels of endotoxin-induced IFN were enhanced 5- to 20-fold by pretreating (priming) macrophages with murine interferons produced by either NDV-induced L cells, which consisted of a mixture of IFN alpha and IFN beta, or IFN gamma produced by spleen cells stimulated with phytohemagglutinin. Studies conducted on the kinetics of IFN release from endotoxin-induced macrophages demonstrated that peak synthesis occurred within 2-4 hr and was completed 6 hr after the start of treatment. The addition of actinomycin D to macrophages, up to 1 hr after exposure to endotoxin, completely inhibited release of interferon, thus indicating that gene transcription was required for interferon synthesis. The inclusion of cycloheximide in the medium of endotoxin or Poly(I) X Poly(C)-induced macrophages, although inhibiting 90% of protein synthesis, resulted in a superinducing effect, in that induced macrophages treated with cycloheximide produced higher levels of IFN than macrophages not treated with the inhibitor of protein synthesis. Antigenic characterization of macrophage IFNs revealed that endotoxin-induced IFN was neutralized to a higher degree than virus-induced IFNs derived from either macrophages or L cells.

The plasma level of lactate dehydrogenase (LDH) activity rises to about ten times the normal level by 4 days after infection of mice with lactate-dehydrogenase elevating virus (LDV). The levels of seven other enzymes are also increased, but to a lesser degree. SJL/J mice demonstrate a unique, genetically controlled 20-fold increase in the plasma level of LDH enzyme after LDV infection, as well as enhanced levels of the other plasma enzymes elevated by LDV infection. Comparison of virus infection in SJL/J and Swiss mice as well as in cultures of peritoneal exudate cells made from them indicated that the time course and extent of virus replication was similar for the two strains of mice. The rate of clearance of intravenously injected rabbit or mouse LDH was found to be impaired to a similar extent in LDV-infected SJL/J and Swiss mice. The effect of LDV infection on the levels of endogenous LDH released as a result of injection of carbon tetrachloride or tumor growth was also similar in the two strains of mice. These results suggest that LDV infection may specifically induce a greater influx of LDH into the plasma of SJL/J mice from an as-yet-unknown source than in other strains of mice.

Cultivated guinea pig peritoneal macrophages were infected with radio-labeled phase I Coxiella burnetii in order to assess the intracellular distribution of ingested rickettsiae. Localization of organisms was determined by fractionation of macrophage homogenates by equilibrium density centrifugation on sucrose gradients. Macrophages isolated from either nonimmune or immune guinea pigs and infected with C burnetii opsonized with immune serum yielded equilibrium density distribution for rickettsiae similar to lysosomal enzymes, suggesting sequestration within macrophage lysosomes. To confirm these observations nonimmune or immune guinea pigs were injected with Triton WR-1339 prior to macrophage harvest to decrease the density of macrophage lysosomes. Triton-laden macrophages infected with opsonized rickettsiae resulted in equilibrium density distribution for lysosomal enzymes and organisms in less dense regions of the gradient. In contrast, when either nonimmune or immune macrophages were infected in the presence of normal guinea pig serum, the distribution of labeled rickettsiae in the gradient did not correspond with lysosomes. We conclude that in the absence of immune serum, ingested C burnetii are not sequestered within macrophage lysosomes. Phagolysomal fusion and subsequent degradation of rickettsiae within the lysosomes of the macrophages appear to occur only when C burnetii are opsonized with immune serum.

Particulate glucan, a beta-1,3-linked polyglucose derived from Saccharomyces cerevisiae, has been demonstrated to have a wide range of immunopotentiating effects. Glucan administration is associated with the modification of a variety of experimentally induced infectious disease states as well as the inhibition of growth of implantable and spontaneous tumors. The present study was designed to evaluate the effect of glucan upon activation of the complement system in rats and guinea pigs. Additional studies were performed to determine the in vitro activating effect of glucan and zymosan on complement activity of human serum. Glucan activated both the classical pathway of normal human sera and the alternate pathways in C2hu-deficient sera in vitro releasing anaphylatoxins such as C3a. The intravenous injection of glucan activated the alternate pathway of guinea pig plasma. The influence of glucan on complement depletion induced by cobra venom factor (CVF) was also ascertained. Complement activation by glucan may contribute, in part, to the enhanced resistance of the host against tumor growth as well as infectious episodes.