EXTRAVASCULAR MOBILIZATION OF NEUTROPHILS

The reaction of rat mast cells to polylysine

The effects of a single intraperitoneal injection of polyamino acids (lysine, glutamic, aspartic) on mast cells of the rat are described. In vitro interaction of mast-cell components with these polyamino acids is also explored. Poly-DL-lysine (but not the acidic amino acids) has both immediate (minutes-hours) and long-term (days-weeks) effects on mast cells. At the dosage selected, some cells evidence rapid fusion of granules and degranulation, but without concomitant swelling; most display intracellular changes only. Neither degranulation nor granule fusion appears to be lethal. Rather, these spur the cell to greater synthetic activity which involves first the Golgi apparatus and subsequently also the endoplasmic reticulum. Early involvement of macrophages and eosinophils is described. Sequential studies after polylysine injection support the following concepts: (a) mast-cell granules exist as "physiological sets," several being confined to a common membranous "sac;" (b) each set can respond independently to applied stimuli; (c) each set can connect directly to the extracellular milieu; (d) poly-DL-lysine binds directly to the granules and stabilizes them; it is not readily digested; (e) mast-cell granules are produced directly; they do not arise by intake of exogenous polysaccharides. It is hypothesized that mast-cell granules are topologically outside the cell while held intimately within extensive cytoplasmic folds and recesses. Mast cells may function by causing intercellular connective tissue fluids to percolate over their granules which may process this fluid in some as yet undefined way(s).

The rate of release of leukocyte pyrogen from rabbit blood incubated with endotoxin

The time course of leukocyte pyrogen liberation from whole rabbit blood incubated at 37 degrees C with various concentrations of proteus endotoxin was studied. The kinetics of the process provide further evidence for the view that leukocyte pyrogen is an independent entity. It was shown that complete liberation of all available leukocyte pyrogen from blood is too slow a process to account for the fevers seen when rabbits are injected with endotoxin. However, very small quantities of leukocyte pyrogen were demonstrated after short periods of incubation which are adequate to account for endotoxin fevers. It was also found that small, but definite, quantities of leukocyte pyrogen are liberated from rabbit blood incubated without endotoxin.

Peritoneal toxicity of water: a model of chronic peritonitis caused by osmotic dysequilibrium in rats

The purpose of this work was to determine whether the osmotic dysequilibrium created by intraperitoneal (i.p.) injection of pure water has any permanent, damaging toxic sequelae. Rats were injected i.p. with pure water on five successive days. Necropsies were performed 1 week after the last injection. Necropsies revealed fibrosis of peritoneal surfaces of liver and spleen, similar to the effects of chemical irritants but milder. The severity of the lesions depended on the dose of water and the number of injections. A few minutes of contact with pure water was sufficient to ensure subsequent development of fibrosis. Soon after the initial injury, the inoculum became less hypotonic and then isotonic. Isotonic or moderately hypotonic electrolyte solutions did not produce peritoneal fibrosis but very hypotonic solutions were toxic. Injection of the synthetic compound 48/80, which is known to cause discharge of mast cell granules, did not produce peritonitis, nor was contamination by endotoxin or by blood responsible for the lesions. Injection of water may be a useful method for investigating the role, if any, of mast cells and/or mesothelial cells in the toxic effects of osmotic dysequilibrium.

Corticotropin-Releasing Factor Receptor 1 in Mouse Spleen: Expression After Immune Stimulation and Identification of Receptor-Bearing Cells

A specific polyclonal Ab against the N-terminal domain of corticotropin-releasing factor (CRF) receptor, type 1 (CRF-R1), was employed to an immunohistochemical analysis of the spleen from naive mice and mice exposed to an immune challenge. Cell types stained with anti-CRF-R1 Ab were identified by their nuclear shapes and colocalization with the cell type-specific markers ER-MP58, ER-MP20, Moma-1, Moma 2, anti-CD3e mAbs, and anti-Ig Ab. Only a few clusters of CRF-R1+ cells were found in spleen sections of naive mice at sites typical for granulopoietic islands. However, a 17-fold increase in the mean number of CRF-R1+ cells was noted within hours following a challenge of acute systemic inflammation induced by i.p. administration of LPS. The majority of these cells were identified as mature neutrophils. CRF-R1 was shown to mediate suppression of the IL-1β secretion by these cells. However, at later time points a large number of granulocyte-macrophage precursors was strongly labeled with anti-CRF-R1 Ab. Western blot analysis of splenic membranes from animals treated with LPS revealed a m.w. of approximately 70,000 for CRF-R1. Subcellular staining patterns were suggestive for the predominant localization of CRF-R1 on granule membranes. CRF-R1 mRNA was detected in spleen but not in bone marrow and peripheral blood leukocytes from naive mice. Thus, it was indicated that CRF-R1 was not produced constitutively by mature or immature neutrophils. Its production was rather triggered by inflammatory stimuli.

Changes in corticosterone levels under different degrees of acute inflammation in mice

Carrageenan of different concentrations was injected into the 6-day-old air pouch in mice. It was found that 12 mg carrageenan caused a significant increase of plasma and exudate corticosterone levels at 24 h, while 1 and 3 mg carrageenan could only induce a significant increase of exudate corticosterone at 4 h. Elevation of corticosterone in both plasma and inflammatory exudate appeared to be correlated, suggesting that the exudate corticosterone was derived from the blood circulation. Injection of exogenous histamine and PGE2 into the air pouch induced a significant increase in exudate levels of corticosterone. However, plasma corticosterone increased significantly only after histamine administration, although a slight increase was observed in those injected with PGE2. These findings thus suggest that endogenous histamine and PGE2 which are released during carrageenan-induced acute inflammation, as shown in our previous work, might be responsible for the increase of corticosterone in both plasma and inflammatory exudate.

Elicitation of peritoneal polymorphonuclear neutrophils from mice

Although the mouse has been used extensively as a model for the study of host-parasite relationships, murine neutrophils have not been used nearly as often as PMNs from other species for in vitro functional assays due to lack of a commonly used procedure for murine neutrophil collection. These studies compared two eliciting agents and characterized the phagocytic and bactericidal activity of murine polymorphonuclear neutrophils elicited from the peritoneal cavity. We examined the effects of mouse strain (BALB/c, C57BL/6 and DBA/2) and sex, eliciting agent (0.2% glycogen vs. 3% fluid thioglycolate medium) and donor sacrifice method (ether vs. cervical dislocation) on the number of neutrophils recovered in peritoneal exudate. The greatest number of neutrophils was harvested when mice were sacrificed 5 h after intraperitoneal injection of 2.5 ml of 3% thioglycolate medium. This method as described allows reproducible collection of adequate numbers of neutrophils for use in in vitro assays of neutrophils phagocytic and bactericidal function.

The effects of endotoxin on CFU-C clonogenic capacity of marrow and spleen cells from RLV-A infected mice

Bacterial endotoxin was used as a granulopoietic stressor in the RLV-A infected mouse as a means of studying the marrow and spleen CFU-C response to this agent. A control group of phenylhydrazine (PHZ)-treated mice was also employed to induce a reduction in hematocrit levels equivalent to that observed in the early and mid-stage of the disease course and was used to determine whether the cloning observed was a manifestation of RLV-A disease or could be attributed solely to the resulting anemia. Both RLV-A infected and PHZ marrow from mice maintained at a hematocrit of 40% exhibited similar but higher than normal clonogenic capacities, whereas RLV-A (hematocrit 40%) spleen had an expanded number of CFU-C's when compared to PHZ treated (hematocrit 40%) mice. Examination of spleens of endotoxin-treated RLV-A (hematocrit 30%) infected mice indicated a 6 to 7-fold increase in splenic CFU-C numbers compared to endotoxin-treated normal mice. PHZ plus endotoxin-treated normal animals (hematocrit 30%) had splenic CFU-C values which were approximately half those of RLV-A infected (hematocrit 30%) endotoxin-treated animals. Results of this experiment suggest a fully operable but greater than normal CFU-C storage pool in the RLV-A infected mouse spleen which does not seem to be due entirely to the anemia.

Decadron in the treatment of cerebral abscess. An experimental study

Forty rabbits were inoculated with Streptococcus pyogenes or Staphylococcus aureus to produce cerebral abscesses. One-third of the rabbits received no treatment and served as controls. One-third received dexamethasone (Decadron) plus an appropriate antibiotic. One-third received only the appropriate antibiotic in the same dosage. The animals were sacrificed 10 days after inoculation and the brains examined. In the control group, an abscess at the stage of granulation tissue encapsulation containing the inoculated organisms was found. The surrounding brain showed a marked inflammatory response. In the Decadron plus antibiotic group, necrotic lesions were found containing the inoculated organisms and surrounded by relatively normal brain. In the group treated with antibiotic alone, healed glial scars were found in relatively normal brain. Our findings are discussed with reference to the medical literature regarding the influence of glucocorticoids on the inflammatory response and the efficacy of antibiotics when this response is suppressed.

Metabolic changes in rabbit articular cartilage due to inflammation

The effect of inflammation on the articular cartilage of rabbit knee joints were studied. The inflammation was induced by intraarticular injections of corton oil or rabbit peritoneal leukocyte lysates. An increase in the activities of various lysosomal enzymes was observed in the synovial fluid as well as in the cartilage of the inflamed joints. Loss of proteoglycans, increased rate of degradation of collagen and proteoglycans, and increased rate of their synthesis were evident in the treated cartilage. The rate of uptake of 3H-thymidine was also increased. A significant change was observed in the type of collagen synthesized by these explants in vitro. In addition to synthesizing their characteristics Type II collagen, the cartilage explants from the treated joints synthesized Type I collagen.

Effects of corticosteroid treatment and inflammation on the cellular content of blood and exudate in mice

Inflammatory exudates have been produced in mice by intraperitoneal injection of thioglycollate broth 24 hr and again 3 hr before collecting of the exudate. The first injection of broth exerts a "priming" effect leading to an enhanced response to the second injection. By this procedure more than 30 x 106 leucocytes of which 78 per cent. were polymorphs were obtained from each mouse. Administration of paramethasone reduced the number of cells in the exudate when given at the same time as broth but not when given 3 hr before collection of the exudate. In contrast paramethasone was equally effective when given either 24 hr or 3 hr before harvest in suppressing the appearance of intravenously injected pontamine sky blue in the exudate. It was striking that treatment with paramethasone which had reduced the number of polymorphs in the exudate had actually increased the number in blood.

Genetic control of host responses to endotoxin

Two pathophysiological effects of endotoxin in mice have been shown to be under the major influence of polygenic inheritance. The first, endotoxemia, was measured by LD(50) assays on hybrids and backcross hybrids of the resistant C(3)H/HeJ and the susceptible A/HJe strains. The LD(50) values of the F1 hybrids and the backcross hybrids were intermediate between the respective parental types. The second effect, the intraperitoneal extravascular leukocyte response to small doses of endotoxin, also was found to follow characteristic patterns of polygenic inheritance. As estimated from an analysis of the variance of mice of the F1 and F2 generations, the degree of genetic determination is approximately 54% for the neutrophil response and 82% for the monuclear response.

The action of cortisone acetate on cell-mediated immunity to infection. Suppression of host cell proliferation and alteration of cellular composition of infective foci

Pulse labeling with tritiated thymidine shows that the response in the mouse to infection with L. monocytogenes includes a large increase in the division of lymphoid cells in the spleen, an increase in the division of macrophages in the liver, and an accumulation of monocyte-derived macrophages at infective foci in the tissues. A single 2.5 mg dose of cortisone acetate given at the beginning of infection greatly delays and suppresses these three components of the host response. The unrestricted bacterial multiplication which follows cortisone treatment is ultimately because of a failure of monocyte-derived macrophages to accumulate at infective foci where they normally express immunity. The accumulation of polymorphs at these sites, in contrast, is enhanced. It is argued that cortisone acetate prevents the accumulation of monocytes at infective foci indirectly by suppressing the production in the spleen of immunologically-committed lymphocytes which are needed to mediate the cellular events at infective foci.

Polymorphonuclear leucocyte chemotaxis in patients with bacterial infections

A new in vitro method of measuring the chemotaxis of polymorphonuclear leucocytes from peripheral blood has been used to calculate a chemotactic index. The mean chemotactic index in 15 patients with bacterial infection (434) was significantly less (P <0.0005) than in 15 normal controls (553) matched for age and sex. The reduction in chemotaxis could be correlated with the duration of the infection, with the greatest impairment being found in those patients with the shortest duration of infection. In five patients studied before and after appropriate therapy the chemotactic index returned to normal values with clearing of the infection. It is suggested that the impairment in chemotaxis may be due to prior phagocytosis of antibody-antigen complexes by the polymorphonuclear leucocytes.

Uptake of colloidal thorium dioxide by mast cells

Mast cells from the peritoneal cavity of the rat were obtained at various times following in situ injection of a colloidal thorium dioxide preparation (Thorotrast). They were prepared for electron microscopy by aldehyde fixation, osmium tetroxide postfixation, and embedding in Epon. Thorotrast was rapidly taken up by mast cells through enhanced or newly elicited surface specializations. It was confined at first to large vesicles which moved to the Golgi area. Subsequently, in a matter of a few hours only, it became associated with progressively more mature granules, including "fully" mature ones. In addition to demonstrating a further phagocytic or pinocytotic activity of mast cells, the findings suggest that mast cell granules share a common membranous investment, and that substances from the tissue environment may theoretically percolate over and interact with the granules. Mast cell function could thus be served primarily by absorptive rather than secretory processes.