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Elicited murine neutrophilic polymorphonuclear leukocytes (PMN) were fractionated by Percoll density gradient centrifugaron into high density (HD) and intermediate density (ID) populations. As described in the accompanying article12HD- and ID-PMN appear to represent "resting" and "activated" cell populations, respectively. Consistent with this possibility, histochemical and biochemical evidence suggested that ID-PMN were degranulated compared to HD-PMN. Myeloperoxidase (MPO) in the ID-PMN population showed increased sensitivity to inhibition by 3-amino-1,2,4-triazole, and HD-PMN exhibited a 2-3-fold increase in chloride and iodide oxidation per unit of MPO activity compared to ID-PMN. When HD-PMN were induced to degranulate in vitro, the remaining cell-associated MPO displayed enzymatic properties characteristic of the activity associated with ID-PMN. The mechanism of this phenomenon was also investigated in vitro using purified human peripheral blood PMN and the synthetic chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine. Differences in cell-associated MPO activity were shown to be related to selective exocytosis of enzymatically and chromatographically distinct forms of the enzyme. These data indicate that, in addition to the well known selective exocytosis of specific and azurophilic granules induced by various agents, selectivity may also occur at the level of enzymatically distinct forms of a particular granule enzyme. Moreover, our observations provide further evidence that density differences may be utilized to fractionate and study the generation of functionally distinct subpopulations of PMN that arise in vivo as well as in vitro following exposure to various stimuli.

When elicited murine peritoneal exudate cells were subjected to Percoll density gradient centrifugation, polymorphonuclear neutrophils (PMN) were found to distribute over a broad spectrum of buoyant densities (1.10-1.06 g/ml). PMN isolated between approximately 1.10 and 1.085 g/ml were referred to as high density PMN (HD-PMN), and those isolated at approximately 1.085-1.06 g/ml were designated intermediate density PMN (ID-PMN). Cells were characterized on the basis of morphology and specific markers: PMN by lactoferrin immunocytofluorescence and macrophages by nicotinamide adenine dinucleotide glycohydrase activity. Macrophages banded near the top of the gradient with a peak at 1.04 g/ml. At increasing times following elicitation, the ratio of HD to ID-PMN decreased. Decreased density of either murine HD-PMN or human peripheral blood PMN could be induced in vitro by exposure of the cells to endotoxin-activated serum. A decrease in buoyant density of human PMN was also demonstrated in vitro using the synthetic chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP). The response was time dependent, related to dose, and appeared to be mediated by the cell membrane receptor for FMLP. A competitive antagonist of FMLP binding, carbobenzoxy-phenylalanyl-methionine, inhibited the density Change with a calculated Kdsimilar to that reported for inhibition of FMLP-induced aggregation, degranulation, locomotion, and superoxide production. The FMLP-induced decrease in PMN density was shown to be directly correlated with increases in relative mean cell volume. The density response is a new measurement of PMN interaction with specific chemotactic factors, which may be important in the generation of PMN heterogeneity observed in elicited peritoneal exudate cells. In addition, this approach offers a means of physically separating "activated" from "resting" PMN and of studying resultant biochemical differences between these cell populations using both in vivo and in vitro systems.

The ontogeny of a 57-Kd cationic antimicrobial protein (CAP57) that has substantial similarities to bactericidal permeability increasing protein (BPI) has been determined immunocytochemically. CAP57 was detected in the granules of mature peripheral blood neutrophils. However, it was absent from other cells of the peripheral blood: eosinophils, red blood cells (RBCs), and mononuclear cells. In human bone marrow, CAP57 was confined to the neutrophilic series. The earliest stage of development of the myeloid cells at which CAP57 was demonstrated was the promyelocyte. Double immunofluorescent labeling showed that CAP57 was detected in cells positive for myeloperoxidase. The absence of lactoferrin in certain cells (promyelocytes) containing CAP57 indicated that CAP57 was synthesized and packaged in a population of granules prior to the development of granules that contain lactoferrin. CAP57 could not be demonstrated in HL60 cells either by enzyme-linked immunosorbent assay (ELISA) or by immunocytochemistry. However, the presence of another granule-associated cationic antimicrobial protein of molecular weight 37 Kd (CAP37) was readily detected in undifferentiated HL60 cells. Amino acid sequence analysis showed that CAP57 and BPI were identical. Further indication of the identity between CAP57 and BPI was that monoclonal anti-CAP57 antibodies cross reacted with BPI. Sucrose density-gradient centrifugations showed CAP57 was confined to a granule population that exhibited a buoyant density intermediate of the previously described light and heavy azurophil granules. Further resolution of the individual azurophil granule populations by Percoll density-gradient centrifugation revealed that CAP57 was most concentrated in the density range of 1.093 to 1.100 g/cc. These results strongly suggest the unique finding that CAP57 may be associated with a heretofore unreported granule type.

Defensins are a newly recognized class of small, cationic polypeptides that have in vitro microbicidal activity toward certain bacteria, fungi, and viruses. Human neutrophil granules were separated into 13 density fractions by using a high-resolution Percoll gradient centrifugation procedure, and the distribution of the three defensin polypeptides in these fractions was determined. Levels of defen-sins and several granule marker proteins were estimated in each fraction from relative staining intensities of bands following acid-urea and sodium dodecyl sulfate-polyacryl-amide gel electrophoresis (SDS-PAGE) of total acid-extractable proteins. These results were confirmed by enzyme immunoassay measurements of defensins and quantitative determinations of the typical azurophil granule components, myeloperoxidase, β-glucuronidase, lysozyme, and elastase. The five higher density granule fractions (H1 through H5) contained fourfold higher relative amounts of defensins as compared with the eight lower density fractions (L1 through L8), accounting for -50% of the total protein. In particular, fraction H5 was especially enriched in defensins but was relatively deficient in myeloperoxidase, β-glucuronidase, lysozyme, and elastase. Ultrastructural morphology showed that fraction H5 contained the largest granules. Seventy percent of these granules exhibited electron-dense rims and electron-lucent central regions when stained with methanolic uranyl acetate-lead citrate, and 70% showed this same characteristic rim-staining pattern after limited reaction (30 minutes) for peroxidase with diaminobenzidine. These distinctively large, rim-stained granules were identified in intact, mature peripheral blood neutrophils as well as in human bone marrow promyelocytes, indicating that their synthesis occurs during early myeloid development. This unusual granule type may play a specialized role in the microbicidal functions of the neutrophil, distinct from that of typical azurophil granules.

Biological activities associated with colony-stimulating factor (CSF) from human leukemic urine were found to be selectively retained on an affinity adsorbent of Con A-Sepharose. Elution of activity was achieved using a linear gradient of either α-methyl-D-mannopyranoside (αMM) or α-methyl-D-glucopyranoside (αMG), and resulted in significant increases in specific biological activity. Rechromatography of appropriate fractions indicated that retention of CSF activities was not artifactual. Pretreatment of the affinity matrix with αMM completely inhibited binding of CSF. Affinity chromatography of CSF on a Blue Dextran-Sepharose adsorbent was found to be an effective method for removing albumin, a major protein contaminant in urinary preparations. Treatment of CSF with neuraminidase had no effect on its in vitroactivity; however, such treatment resulted in an increase in the isoelectric point of CSF from pH 3.5 to pH 4.7, as determined using both sucrose and polyacrylamide gel stabilized pH gradients. Relatively broad regions of biological activity were observed following isoelectric focusing of both neuraminidasetreated and untreated CSF, suggesting that activity was associated with a heterogeneous/polydisperse population of molecular species.The authors thank E. S. Mingioli, M. Parker, D. LaVia, and B. Jambois for expert technical assistance. We are indebted to Dr. J. Mendicino for informing us about the properties of Blue Dextran-Sepharose. We also thank Dr. E. R. Stanley, who, following completion of the present studies, brought to our attention an earlier workshop report of related work, and, indirectly, a paper by Iscove et al.(34), who showed that colony-stimulating activity was retained on an affinity matrix similar to ours.

A radioimmunoassay was developed for murine lactoferrin (LF), a non-heme, iron-binding glycoprotein which appears to be a specific biochemical marker of differentiation in several cell types. Lactoferrin was labeled with 125 I by the chloramine-T method to yield a product having 20 μCi/μg protein and an isotope incorporation of 0.6 atoms of I per molecule. Separation of bound and free lactoferrin was accomplished by either of two procedures, a double-antibody technique or precipitation in the presence of 50% saturated ammonium sulfate. The entire assay, including counting, was accomplished in less than 2 days and had a lower limit of sensitivity and a range of 1 ng/ml and 1-32 ng/ml, respectively, using rabbit antiserum in a dilution of about 1 : 10,000. The binding between LF and rabbit antiserum exhibited two association constants having values of 1.8 × 10 and 1 × 10 1/mole. The assay was specific for lactoferrin and no cross-reactivity was observed with transferrin, a similar non-heme, iron-binding glycoprotein. Human lactoferrin specifically reacted with anti-mouse lactoferrin, but the binding was approximately 8000 times weaker than observed with mouse lactoferrin. Values for lactoferrin in milk and bone marrow granulocytes were obtained which agreed with levels obtained using other methods.

The nature of the compartmentalization of catalase in human myeloid cells is an unresolved issue. Using a rabbit polyclonal antibody specific for catalase, indirect immunocy-tofluorescence of immature leukemic promyelocytes (HL-60 cells) showed a pattern of small, sharp, punctate staining in the cytoplasm of all cells, while mature neutrophils showed a larger diffuse, flocculent pattern of cytoplasmic staining. Differential centrifugation of nitrogen cavitates of HL-60 cells indicated that the putative catalase-containing compartment was relatively fragile compared with the compart-ment(s) that contained myeloperoxidase (MPO), β-hexos-aminidase, β-glucuronidase, and lysosomal α-mannosidase activities. Parallel studies using dimethylsutfoxide (DMSO)-induced HL-60 cells and mature neutrophils showed that, in the course of differentiation, there was an apparent shift in the localization of catalase from the granule fraction to the cytosolic fraction. Percoll-sucrose density gradient centrifugation of HL-60 cell cavitates showed a catalase-containing compartment with a mean peak density (1.05 g/mL) significantly lower than that of the major myeloperoxidase-containing compartment (1.08 g/mL); in mature neutrophils, catalase activity comigrated with lactate dehydrogenase (LDH) activity. Catalase in isolated fractions was protected from proteolysis in the absence, but not in the presence, of 0.1 % Triton X-100. Oigitonin titration experiments confirmed the compartmentalized nature of catalase in immature HL-60 cells and were consistent with a cytosolic localization in mature neutrophils. Ultrastructural localization of catalase by Protein A-gold immunocytochemistry demonstrated four to six catalase-containing compartments in all HL-60 cell profiles. In mature neutrophils, catalase was localized primarily in the cytoplasmic matrix, although in fewer than 2% of the cell profiles, one to two catalase-containing compartments were observed. The changes in catalase localization that occur during myeloid differentiation appear to be similar to the changes that occur during erythroid and megakaryocytic differentiation, and may have potential clinical significance in the classification of acute leukemia and in the development of drug resistance.

Human lactoferrin (LF) has been reported to inhibit in vitro granulopoiesis by means of decreasing colony-stimulating activity production by monocytes. We performed a series of experiments to determine if the reported experimental results could be replicated using highly purified murine LF and murine target cells. Three different types of experiments were performed. (1) Medium was conditioned by lung, femoral shaft, and adherent peritoneal cells in the presence and absence of LF, and the granulopoietic stimulating activity in the conditioned media was assayed by means of a 7-day agar colony assay and a 3-day liquid slide chamber assay, which quantitates 3H-TdR incorporation into DNA. (2) In cultures stimulated by an underlayer of adherent peritoneal cells, marrow cell colony formation in agar was determined after 7 days of culture in the presence or absence of LF. (3) LF was added to 3-day liquid marrow cell cultures that had been stimulated by lung or femoral shaft conditioned media. In all experimental situations, highly purified, iron-saturated LF in concentrations up to 107Mhad no effect on in vitro granulopoiesis. These results do not support LF’s reputed regulatory role in granulopoiesis.

Previous studies on the fractionation of human neutrophil granules have identified two major populations: myelo-peroxidase (MPO)-containing azurophil, or primary, granules and MPO-deficient specific, or secondary, granules. Peripheral blood neutrophils from individual donors were lysed in sucrose-free media by either hypotonic shock or nitrogen cavitation. Using a novel two-gradient Percoll density centrifugation system, the granule-rich postnu-clear supernatant was rapidly (ten minutes) and reproducibly resolved into 13 granule fractions (L1 through L8 and H1 through H5). Granule flotation and recentrifugation experiments on both continuous, self-generated and multi-ple-step gradients using individual and mixed isolated fractions demonstrated that the banding patterns were isopycnic and nonartifactual. Isolated granules were intact based on the findings that biochemical latency of several granule enzymes was >95%, and thin-sectioned electron micrographs demonstrated intact granule profiles. Biochemical analyses of the granule marker proteins MPO, β-glucuroni-dase, lysozyme, and lactoferrin indicated that a number of the fractions were related to the major azurophil and specific granule populations. Lactoferrin was found in ten of 13 fractions (L1 through L8, H1 to H2), whereas MPO was found in every fraction. Consistent with these biochemical data, all fractions exhibited varying degrees of heterogeneity based on ultrastructural morphology and cytochemistry, including diaminobenzidine (DAB) reactivity for peroxidase and periodate-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining for complex glycoconju-gates. A variable but significant percentage (23% to 70%) of the granules in fractions L1 through L8 and H1 and H2 showed DAB reactivity, while about 90% of the granules in fractions H3 through H5 were peroxidase positive. These results demonstrated that DAB-reactive granules spanned the entire range of granule size and density. Ultrastructural PA-TCH-SP staining of isolated granule fractions revealed patterns similar to those of granules in intact neutrophils at different stages of development. Granules from human acute promyelocytic leukemia cells (HL-60) exhibited a surprisingly low density compared with typical azurophil granules from normal, mature neutrophils. The data suggest that both functional and maturational differences contribute to granule heterogeneity, and provide a new practical and conceptual framework for further defining the phenomenon of neutrophil granule heterogeneity.

A liquid culture system employing slide chambers was developed to facilitate the study of proliferation and differentiation of mouse neutrophilic granulocytes and cells of the monocyte-macrophage series. Cultures were initiated with 1-2.5 × 104light density marrow cells which had been fractionated on Ficoll-Hypaque. In the presence of colony-stimulating activity (CSAHU), two types of clusters were observed. One was tight, spheroidal, and composed of neutrophilic granulocytes, while the other was a loose grouping of flattened cells of the monocyte-macrophage series. The slide chamber culture is adaptable to microscopic assay techniques (e.g., cluster size, autoradiography, immunofluorescence) as well as quantitative biochemical methods (e.g., rate of 3H-thymidine incorporation, DNA quantitation). We have demonstrated both a shortening of the generation time of granulocytes in tight clusters and increasing rates of 3H-thymidine incorporation into DNA, with a corresponding increase in total culture DNA as a function of CSAHUconcentration. Granulocytic differentiation in the tight spheroidal clusters has been demonstrated by histochemical stains and immunofluorescence of an antibody to a marker protein specific for the secondary granule of the neutrophil (lactoferrin).

AN EVER-EXPANDING sector of public and private life has been brought under the influence of air-conditioning. From a luxury and an exceptional attraction, air-conditioning has become a necessity of everyday life and constitutes in many climatic regions part of the standard indoor environment of modern man. All along, observations have been made on the physiologic effect of air-conditioning and its therapeutic applications. But engineering has taken the initiative, and there is a lag before medicine is able to catch up to the technological development.21 By now, however, the time may have come to reevaluate the effects of air-conditioning on patients with acute or chronic diseases of the ear, nose, and throat. While atmospheric factors, including air-conditioned environments, affect the entire organism, their impact is probably most immediate with regard to the upper respiratory tract.In the following survey it is taken for granted that the air-conditioning system is correctly