The isolation and selected properties of blood monocytes

Human alveolar macrophages: effects of endotoxin in vitro

Experiments were performed to evaluate the in vitro effects of Escherichia coli lipopolysaccharide on viability and function of human alveolar macrophages. Alveolar macrophages were obtained by fiberoptic bronchoscopy and saline bronchial lavage from 12 normal, nonsmoking volunteers. Cells were incubated with different concentrations of E. coli endotoxin for 1 and 24 h. Endotoxin (10 microgram/ml and more) was cytotoxic for alveolar macrophages after 24 h of incubation and induced significant inhibition of phagocytosis, adherence, and spreading. The effects of endotoxin on alveolar macrophage viability and function were dose and time dependent and were not influenced by indomethacin. Thus, human alveolar macrophages, like other mononuclear phagocytes, are extremely sensitive to endotoxin effects; these observations may be relevant in conditions in which endotoxin may be in contact with alveolar macrophages in vivo: endobronchial infections with gram-negative organisms, byssinosis, chronic bronchitis of grain handles, and humidifier fever.

The isolation and purification of human peripheral blood monocytes in cell suspension

A simple method for the isolation of human peripheral blood monocytes in cell suspension is described. The method is based on the adherence and detachment characteristics of monocytes during their in vitro cultivation and does not require any gradient centrifugation or modulating substances. The mean percentage of monocytes recovered from different donors was 81.9% (60-100%) of the original phagocytic cells found in the peripheral blood of the tested donors and the cell suspensions obtained consisted of more than 95% of monocytes. The monocytes isolated in suspensions show high activity in various monocyte functions tested.

Phorbol diester-induced macrophage differentiation of leukemic blasts from patients with human myelogenous leukemia

Phorbol esters, including 12-O-tetradecanoylphorbol 13-acetate (TPA), induce terminal macrophagelike differentiation of cells from human acute myelogenous leukemia lines. We report that myelogenous leukemia cells obtained from patients undergo macrophagelike differentiation after exposure to TPA. The myeloid leukemic cell cultured with TPA became adherent to charged surfaces with long filamentous pseudopodia; developed positive staining for alpha-napthyl acetate esterase, increased lysozyme secretion, reduced nitroblue tetrazolium, and acquired the ability to phagocytose candida. Cells from patients with lymphocytic leukemia did not become macrophagelike when cultured with TPA.

Synthesis and secretion of cystic fibrosis ciliary dyskinesia substances by purified subpopulations of leukocytes

Cultured peripheral blood leukocytes (PBL) from individuals homozygous or heterozygous for the defective gene causing the inherited disease cystic fibrosis (CF) secrete three different ciliary dyskinesia substances (CDS), which can be detected by their activity in vitro in a rabbit mucociliary bioassay. Their PBL also release substances that promote mucus expulsion and destruction of the ciliated epithelium. In the present study the relative numbers of lymphocytes (T, B, and null), monocytes-macrophages (Mphi), and polymorphonuclear neutrophils were found to be normal in subjects with the CF gene, as were the responses of their PBL to phytohemagglutinin and pokeweed mitogen. Using purified subpopulations of leukocytes, we obtained evidence that both monocytes and T lymphocytes can secrete CDS in vitro with no requirement for cooperation with other lymphocyte subsets, whereas B and "null" lymphocytes probably require either differentiation or cellular cooperation for optimal secretion of CDS. Mucus expulsion and tissue destruction were produced by substances released primarily from polymorphonuclear neutrophils and secondarily from Mphi. Using cycloheximide and actinomycin D, we obtained evidence that CDS accumulation requires active protein synthesis and is not dependent on newly synthesized RNA, at least in short-term cultures. Gel filtration chromatography of active culture supernates showed that T lymphocytes synthesized only a CF-specific CDS, whereas Mphi synthesized all three CDS found in PBL cultures. Evidence is presented that one CDS is related structurally to C3a, since it can be removed with rabbit antisera specific for human C3a.

Low density lipoprotein receptor activity in human monocyte-derived macrophages and its relation to atheromatous lesions

Human peripheral monocytes, isolated from a previously unused source (a leukocyte concentrate byproduct of the plateletphoresis procedure for platelet transfusion), transformed into macrophages while cultured with 5% human serum or isolated lipoprotein fractions. Used for the study of their cholesterol (Chol) metabolism, these human monocyte-derived macrophages had a high-affinity receptor that is saturable, specific for low density lipoprotein (LDL) and maximally induced by incubation for as little as 24 hr in medium devoid of lipoproteins or Chol. Macrophages were shown to have separate receptor activity for 125I-labeled LDL and 125I-labeled acetylated LDL; macrophages that had been incubated with lipoprotein-depleted serum degraded native and acetylated LDL at similar rates. The receptor for LDL was functional in maintaining Chol homeostasis, as demonstrated by feedback inhibition of Chol synthesis after culture with LDL or very low density lipoprotein (VLDL). The Chol content of macrophages was doubled by incubation with medium containing VLDL compared to incubation with LDL (60 microgram of Chol per ml of medium). Incubation with native lipoproteins did not lead to accumulation of esterified Chol by macrophages. Changes in the Chol metabolism of macrophages, rather than modifications in circulating LDL, may cause these cells to store cholesteryl ester and take on the characteristics of cholesteryl ester-laden macrophages of atheromatous lesions.

Purification of human monocytes: isolation and collection of large numbers of peripheral blood monocytes

Monocytes from human peripheral blood were purified by elutriation centrifugation. Up to 1.5 x 10(9) peripheral blood mononuclear cells could be separated in isotonic media to yield 6--8 x 10(8) lymphocytes with 95% purity and 1.5--2.5 x 10(8) monocytes with greater than 90% purity. The temperature at which elutriation was performed determined the purity of the monocyte fraction. Both the lymphocyte and monocyte fractions were characterized by cell sizing and histochemical staining. Most of the myeloperoxidase positive mononuclear cells (monocytes) had a modal volume of 378 micrometer 3 while 10% were within the modal volume of the lymphocytes, 131 micrometer 3. Thus, there are two populations of cells with histochemical properties of monocytes which are separable by size. The collection and isolation of human peripheral blood monocyte populations in large numbers will facilitate studies of their functional characteristics.

Enhancement of the growth of blood monocytes in agar cultures by haemolysates

Mouse blood monocytes grow well in liquid but poorly in agar medium. In this study the effect of haemolysate on the clonal growth of blood monocytes in agar cultures was investigated. The results suggested that haemolysate from mouse or rat red blood cells contains a factor(s) that can render the murine blood monocytes able to grow well in agar culture (anchorage-independent growth). The mechanism of action of the enhancing factor(s) is discussed.

Lysosomal acid phosphatase: activity and isoenzymes in separated normal human blood cells

The present study was devised to investigate the activity and isoenzymes of lysosomal acid phosphatase in individual normal human blood cells, including the T- and B-population of lymphocytes, with the aim to contribute to the classification of haematopoietic neoplasias on the basis of cell specific isoenzyme patterns. Platelets, erythrocytes, granulocytes, monocytes and T-lymphocytes were isolated from blood by gradient centrifugation or immune adsorption. B-lymphocytes were obtained from human tonsils. After purity control and isolation of lysosomes the concentration of acid phosphatase was assayed using the conventional spectrophotometric method. Isoenzymes were separated by isoelectric focusing on polyacrylamide thin layer slabs. Monocytes revealed the highest activity with 14 mU/10(7) cells, about three times more than granulocytes. T-lymphocytes showed an activity of 2.85 mU/10(7) cells and B-lymphocytes of 1.83 mU/10(7) CELLS. The lowest activity was found in platelets with 0.08 mU/10(7) cells. Granulocytes showed 12 isoenzyme bands, whilst the number for monocyte, B-lymphocytes, T-lymphocytes and platelets were respectively 11, 12, 1 and 4 isoenzyme bands. Thus it became evident that the different blood cell populations can be distinguished on the basis of their acid phosphatase isoenzyme pattern.

Replication of rubella virus in human mononuclear blood cells

Rubella virus was capable of replicating in both unstimulated and phytohemagglutinin-stimulated cultures of human mononuclear blood cells. Monocyte-derived macrophages were the main cell type responsible for viral replication. The susceptibility of macrophages increased during cultivation. Phytohemagglutinin-stimulated lymphocytes were able to support replication to a limited degree. No viral replication was detected in unstimulated lymphocytes. Both stimulation and viral replication in phytohemagglutinin-treated lymphocyte cultures were enhanced by the addition of murine macrophages. Human leukocyte interferon depressed the production of virus in these combined cultures. The finding that rubella virus is able to replicate in human lymphocytes as well as in macrophages may contribute to understanding the mechanisms of the suppressive effect of the virus on in vitro lymphocyte phytohemagglutinin responsiveness and in vivo immune functions.

Kinetics of phagocytosis of Staphylococcus aureus by alveolar and peritoneal macrophages

The rate of uptake of radiolabeled Staphylococcus aureus by macrophages in vitro was studied by use of Lineweaver-Burk analysis. It was found that competition for ingestion by excess unlabeled particles, either staphylococci or unrelated particles, resulted in diminished uptake of the labeled particles and that opsonization of particles with specific antiserum enhanced that uptake solely by altering the maximum velocity of uptake (Vmax). Uptake of radiolabeled staphylococci opsonized with specific antiserum was not inhibited by excess numbers of unopsonized organisms; the ingestion was inhibited by excess numbers of opsonized unlabeled organisms, and that inhibition was characterized by depression of Vmax. Inhibition of phagocytosis by indoacetate and cytochalasin B resulted from depression in both Vmax and Michaelis constate (Km). In addition, the phagocytic function of macrophages improved during in vitro culture, a phenomenon which was particularly striking for alveolar macrophages. That enhancement of activity resulted from improvements in both Vmax and Km. Addition of opsonizing antibody at any stage of in vitro maturation resulted in further increases in phagocytic uptake, increases which affected only Vmax. The in vitro maturation of phagocytic function by alveolar macrophages could be inhibited by both 2-deoxy-D-glucose and cycloheximide, but not by culture in hypoxia. The data indicate that the terms of Lineweaver-Burk analysis cna be correlated with functional aspects of phagocytosis and that Vmax represents the avidity of the macrophage surface for the particle, whereas Km is an index of the capacity of the cell for ingestion.

Enhanced hydrogen peroxide release from macrophages stimulated with streptococcal preparation OK-432

Wheat germ lectin was found to be a potent triggering agent for hydrogen peroxide release from mouse peritoneal macrophages. Macrophages stimulated by intraperitoneal injection of OK-432, a lyophilized attenuated streptococcal preparation, were highly responsive to wheat germ lectin.

Long-term human peripheral blood monocyte cultures: establishment, metabolism and morphology of primary human monocyte-macrophage cell cultures

Human peripheral blood monocytes were maintained in in vitro culture for periods up to 4 months using a non-human serum source. Monocytes were cultured in Dulbecco's modified Eagle's medium buffered with 20 mM HEPES and containing 10% horse serum and 10% foetal calf serum. The metabolic and morphological changes which occur in vitro were investigated using microtitre, Linbro and T 25 cultures. During culture, monocytes increased in size, had increased membrane activity as visualized by SEM, and differentiated into a morphologically heterogeneous population of fusiform and epithelioid shapes. These cell types retained the ability to phagocytose E glut and EA and to rosette with EA and EAC. Larger giant polynucleated cells were also observed during culture; many of these lacked the ability to bind or phagocytose inert or antibody-coated erythrocytes. Increases in lysozyme release and acid phosphatase activity also occurred during culture. Cultured monocytes exhibited characteristic profiles of leucine and uridine uptake with maximal activity observed by 5 days of culture. There was no detectable uptake of thymidine. Detailed analysis of regulatory processes involved in monocyte growth and differentiation could be performed with this in vitro system.

Mechanisms in the suppression of delayed hypersensitivity in the guinea pig by 6-mercaptopurine. II: Kinetic and morphologic studies on the monocyte-macrophage component

The effect of 6-mercaptopurine on the development and expression of delayed hypersensitivity was studied in the guinea pig. Results indicated that 6-MP produced its suppressive effects primarily by action on cells of the monocyte-macrophage series. Suppression could occur under conditions of both developing and pre-established delayed hypersensitivity. The defect primarily involved newly synthesized, bone marrow-derived monocytes. Marked alterations in monocyte macrophage generation and distribution, especially the T1/2 of circulating monocytes were demonstrated. Suppressive effects were associated with the appearance of a unique morphologic microscopy. Finally, the in vivo expression of delayed hypersensitivity correlated better with a variety of parameters relating to qualitative macrophage function and distribution rather than those relating to quantitative macrophage levels.

Cell-mediated immunity to varicella-zoster virus measured by virus inactivation: mechanism and blocking of the reaction by specific antibody

The process whereby varicella-zoster (V-Z) virus is inactivated in vitro by immune human peripheral blood leukocytes stimulated with V-Z antigen was examined. It was found that stimulation of leukocytes by V-Z antigen, but not by other viral antigens, was required for inactivation of V-Z virus to occur. Viral inactivation could be blocked by addition of V-Z antiserum to either the stimulation phase of the reaction or the inactivation phase, further demonstrating the specificity of the reaction. In addition these blocking experiments suggested that modulation of V-Z membrane antigen by antiserum occurred with an accompanying loss of immunological recognition of virus-infected cells. Inactivation of V-Z virus in vitro in this study appeared not to be dependent upon the secretion of interferon or upon antibody-dependent cellular cytotoxicity. The specific cells required for V-Z inactivation were T lymphocytes and monocytes (macrophage precursors).

Role of macrophages in natural resistance to virus infections

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Human monocyte-lymphocyte interaction and its enhancement by levamisole

We investigated the role of monocyte-lymphocyte interaction in the transformation of human peripheral blood lymphocytes by the mitogen concanavalin A (Con A). Human monocytes were separated from lymphocytes and were transiently exposed to Con A. The Con A-pretreated monocytes were able to subsequently bind autologus lymphocytes by a process that was selective for T cells. This interaction required the initial presence of Con A at the monocyte surface, and became independent of surface bound ligand after 72 hr. Levamisole, an agent thought to facilitate the participation of monocytes in the cellular immune response, enhanced the binding of lymphocytes to monocytes at low concentration of Con A (5--10 micrograms/ml). Levamisole did not lead to mitogen independent lymphocyte binding. The association between lymphocytes and Con A-pretreated monocytes resulted in the mitogenic transformation of lymphocytes in the absence of soluble Con A in the medium. These results suggest that, in addition to any possible soluble mediators, direct lymphocyte-monocyte contact is required for optimal mitogenic transformation. This T-cell-monocyte interaction over time becomes independent of cell-surface mitogen. The ability of levamisole to enhance this interaction may explain levamisole's capacity to stimulate lymphocyte proliferation.

Strain-dependent cytotoxic effects of endotoxin for mouse peritoneal macrophages

The cytotoxic effects of bacterial lipopolysaccharides (LPS) on mouse leukocytes have been examined in vivo and in vitro. Intraperitoneal injection of LPS into C57BL/6 mice greatly reduced the recovery of mononuclear cells; LPS was cytotoxic for macrophages, but had a mitogenic effect on lymphocytes. Similar effects of LPS on peritoneal leukocytes were observed in vitro. When monolayers of adherent peritoneal cells were studied in vitro, cytotoxicity was also observed, suggesting that the effect of LPS on macrophages is direct and does not require participation by lymphocytes. Entirely different results were obtained when peritoneal macrophages from LPS-resistant C3H/HeJ mice were studied. LPS failed to activate lymphocytes and was not cytotoxic for macrophages in vitro or in vivo. The effect of LPS on polymorphonuclear leukocytes appeared to be the same in all mouse stains studied. Lipid A was shown to be the most biologically active portion of the LPS molecule. Whereas polysaccharide-deficient endotoxins extracted from rough mutants of Salmonella typhimurium were cytotoxic for macrophages in vitro, polysaccharides that lacked esterified fatty acids did not exhibit this activity. Since LPS may mediate its effects through affinity for mammalian cell membranes, the cellular unresponsiveness of C3H/H3J mice to LPS may reflect an inability of cells from LPS-resistant strains to interact with LPS at the membrane level.

Abortive and productive infections of human mononuclear phagocytes by type I herpes simplex virus

The ability of Type I herpes simplex (HSV) to replicate in normal human monouclear phagocytes was investigated. Mononuclear leukocytes were obtained from the peripheral blood of patients by Ficoll-Hypaque gradient centrifugation, and the monocytes were isolated by allowing the cells to adhere to tissue culture dishes. The monocytes (10(5.0) cells) were infected (10(7.0) PFU HSV) either immediately after isolation or were cultured in vitro for varying numbers of days and were then infected. Inoculation of freshly isolated monocytes resulted primarily in an abortive infection. HSV antigens were produced by the cells, as determined by a indirect fluorescent antibody technique, and empty herpes capsid structures were detected by electron microscopy of the inoculated monocytes; however, no increase in virus titer was noted in the cultures. Inoculation of viable cells that had been maintained for 7 days in culture resulted in a productive infection. An increase in titer was noted 24 hours after inoculation, and normal virus maturation was documented by ultrastructural study of the infected cells. The experiments show that the interaction of HSV with human mononuclear phagocytes is complex, and the data suggest that whether or not the cell replicates infectious virus may depend on the functional activity of the cell.

Immunologic responsiveness of the C3H/HeJ mouse: differential ability of butanol-extracted lipopolysaccharide (LPS) to evoke LPS-mediated effects

The lipopolysaccharide (LPS)-protein complex extracted from the cell wall of Escherichia coli K235 by the butanol-water technique has been shown to evoke a mitogenic response in bone marrow-derived (B) lymphocytes from the C3H/HeJ mouse strain. These mice are resistant to the effects of LPS extracted with phenol. Therefore, the ability of butanol-extracted LPS to modulate a spectrum of C3H/HeJ B-cell functions was investigated. Both butanol-extracted (LPS-B) and phenol-extracted (LPS-P) LPS preparations activated responder C3H/St spleen cell cultures to polyclonal antibody production, while only LPS-B activated C3H/HeJ spleen cells. Both LPS-P and LPS-B acted as adjuvants when injected after aggregated human gamma globulin (HGG) in C3H/St mice, but neither preparation was effective as a adjuvant in C3H/HeJ mice. LPS-P injected with deaggregated HGG (tolerogen) into LPS-sensitive mice has been shown previously to inhibit the induction of tolerance HGG. In the present studies, it was shown that LPS-B, but not LPs-p, was able to inhibit tolerance induction to HGG in the C3H/HeJ, whereas both preparations were effective in the C3H/St. LPS has also been shown to bypass tolerant T cells in LPS-sensitive mice late in tolerance to HGG at a time when B cells are responsive. However, in the C3H/HeJ, neither LPS-B nor LPS-P was capable of this function. The responsiveness of these B cells to HGG was demonstrated in transfer experiments. Thus, in the C3H/HeJ, LPS-B stimulates mitogenesis, polyclonal B-cell activation, and inhibition of tolerance induction, but cannot act as an effective adjuvant or as a bypass mechanism to activate B cells in the presence of tolerant T cells. The explanation for this pattern of responses may be attributable to yet another cellular defect in the C3H/HeJ mouse.

Specific lethality of silica for human peripheral blood mononuclear phagocytes, in vitro

Human peripheral blood mononuclear cells, cultured in the presence of 100 microgram/ml protein-coated silica particles, were studied to determine changes in number and function of monocytes, immunoglobulin bearing (B), sheep red blood cell rosetting (T) lymphocytes and the effector cells of antibody dependent cell-mediated cytotoxicity (ADCC). After 24-48 h, phagocytic cells were effectively eliminated from culture but there was no significant reduction in number or function of T or B lymphocytes or in ADCC to cell line targets. ADCC to erythrocyte targets was inhibited but not completely blocked. It is concluded that silica is a specific toxin for human peripheral blood mononuclear phagocytes and may be useful in in vitro immunological studies as a means of eliminating or determining the role of these cells without resort to separation methods which result in losses of cells other than monocytes.

Two-step separation of human peripheral blood monocytes on discontinuous density gradients of colloidal silica-polyvinylpyrrolidinone

Normal human peripheral blood monocytes were purified by a two-step separation. The first step, the standard Ficoll--Hypaque (F--H) buoyant density centrifugation, yielded mainly mononuclear cells, of which 24 +/- 9% were monocytes. Isopycnic centrifugation on discontinuous gradients of colloidal silica polyvinylpyrrolidinone (CS-PVP) further separated these mononuclear cells. The density interface between 1.070 and 1.060 g/ml yielded 82 +/- 7% monocytes, 5 +/- 4% granulocytes and 13 +/- 8% lymphocytes. Sixty-six percent of the monocytes obtained after F--H separation were recovered in this layer. The monocytes were intact and viable and retained their ability to phagocytose and kill Candida pseudotropicalis and to spread on glass coverslips. Motility (both random and towards a chemoattractant) was retained but was quantitatively less than after F--H separation alone. The relative purity of the monocyte population allowed assessment of major histocompatibility surface antigens by serotyping. This confirmed the presence of HLA and Ia-like antigens on monocytes.

[Penicillin-induced immunhaemolytic anaemia. In vitro studies using separated monocytes (author's transl)]

Under certain conditions human monocytes were able to bind and ingest red cell-antibody complexes in vitro. Using penicillincoated red cells and purified monocytes we investigated sera of patients with penicillin allergy. It was shown that sera containing IgG-antibodies against penicillin induced the binding of penicillin-coated red cells to isolated monocytes provided IgG-antibodies of high titer were present. Inhibition and absorption tests demonstrated the specificity of the reaction in terms of IgG-antibodies and the drug. Monocyte binding was also studied in respect to the cross reactivity of penicillin antibodies and cephalosporins. We concluded that antipenicillin-antibodies of the IgG-class were able to induce an immunphagocytosis in vitro, if the drug was present in the test system. The reaction was dependent on the amount of antibodies of the IgG-class.

A role for adenosine deaminase in human monocyte maturation

The occurrence of a deficiency of adenosine deaminase (ADA) activity in some patients with severe combined immunodeficiency suggests a possible relationship between the activity of ADA and the aberration of the immune system. To help delineate the function of ADA in the immune response we have examined its role in monocyte maturation. When incubated in vitro, peripheral blood monocytes transformed, within 3 days, to macrophagea as assessed by phase-contrast microscopy and an increase in the specific activity of the lysosomal enzyme acid phosphatase. The specific activity of ADA increased as much as ninefold, reaching a peak after the 1st day in culture, while the activities of other enzymes involved in the purine salvage pathway were not altered. Sucrose density ultracentrifugation of extracts prepared immediately after the isolation of monocytes revealed the presence of two forms of ADA with molecular weights of approximately 30,000 and 110,000. The increase in ADA specific activity during monocyte cultivation correlated with an increase in the activity of the smaller molecular species. A specific inhibitor ADA, erythro-9-(2-hydroxy-3-nonyl) adenine, prevented the increase in acid phosphatase activity, as well as the morphological changes associated with the monocyte maturation. These data suggest a role for ADA in monocyte to macrophage maturation. In view of the central role of macrophages in immune function, this observation may relate to the association of combined immunodeficiency and a deficiency of this enzyme.

Correction of characteristic abnormalities of microtubule function and granule morphology in Chediak-Higashi syndrome with cholinergic agonists

Chediak-Higashi (CH) syndrome is a genetic disorder of children and certain animal species including the beige mouse. We have previously described a membrane abnormality in CH mouse polymorphonuclear leukocytes (PMH). Whereas normal mouse PMN do not form surface caps with concanavalin A except after treatment with agents such as colchicine that inhibit microtubule assembly, CH mouse PMN show spontaneous cap formation. This capping is inhibited by 3',5 cyclic guanosine monophosphate and by the cholinergic agonists carbamylcholine and carbamyl beta-methylcholine that increase 3',5' cyclic guanosine monophosphate generation. These data suggested that microtubule function may be impaired in CH syndrome perhaps secondary to an abnormality in 3',5' cyclic guanosine monophosphate generation. The cholinergic agonists were also shown to prevent development of the giant granules that are pathognomonic of CH syndrome in embryonic fibroblasts isolated from CH mice and cultured in vitro. In this report it is shown that an extreme degree of spontaneous concanavalin A cap formation is also characteristic of peripheral blood PMN from two patients with CH syndrome. This indicates an abnormality of microtubule function in CH syndrome in man. 3',5' cyclic guanosine monophasphate, carbamylcholine, and carbamyl beta-methylcholine reduce spontaneous capping in CH cells. In addition, it is shown that monocytes isolated from the patients' blood and incubated in tissue culture generate a large complement of abnormal granules. When the same cells mature in vitro in the presence of carbamylcholine or carbamyl beta-methylcholine, the proportion of cells containing morphologically normal granules is significantly increased. These responses can be reproduced in vivo in the beige (CH) mouse. Animals treated for 3 wk and longer with carbamylcholine or carbamyl beta-methylcholline show normal granule morphology and a normal degree of concanavalin A cap formation in peripheral blood PMN leukocytes.

Changes in granular endoplasmic reticulum induced in cultured human monocytes by colony stimulating factor

The supernatant portion of cultured human monocytes produces a biological factor known as colony stimulating factor. The addition of culture fluid containing colony stimulating factor to cultured human monocytes produced morphologic changes in the granular endoplasmic reticulum. Granular endoplasmic reticulum changed its appearance from long slender cisternae to a concentric pattern (whorls) averaging seven rows per structure 120 min following the addition of culture fluids containing colony stimulating factor.

The induction of human multinucleated monocytes in culture

The formation of multinucleated giant cells in vitro has been studied using human monocyte cultures. Multinucleated monocytes appeared early in the course of the culture, indicating that they are not purely a phenomenon found only in aging cultures. In 4 of the 33 normal adults, more than 20% of multinucleated forms appeared in the cultures. Supernatants from early monocyte cultures of those subjects having a high incidence of multinucleated cells induced the formation of multinucleated cells in other cultures. This effect did not occur when supernatant from subjects with low counts of multinucleated cells were incubated with other monocyte cultures.

In vitro detection of cellular immunity to melanoma antigens in man by the monocyte spreading inhibition test

In vitro inhibition of monocyte spreading (a correlate of cellular immunity) was used to detect cell-mediated immune reactions of melanoma patients to specific melanoma antigens. Two soluble preparations of human melanoma antigens (MA-1 and MA-2) and one of a breast carcinoma (BCA) were prepared. The preparations were incubated in vitro with mononuclear cells isolated from the blood of 24 patients with melanoma, six patients with malignancies other than melanoma and 14 healthy donors. Spreading of monocytes from healthy donors was not inhibited by either MA-1 and MA-2 or BCA. MA-1 and MA-2 significantly inhibited the spreading of monocytes from patients with melanoma, while monocytes from patients with other malignancies were not affected. Spreading of monocytes from patients with melanoma was inhibited by the preparation of BCA. We conclude that inhibition of monocyte spreading can detect, in vitro, a cellular immune reaction to specific melanoma antigens in patients with melanoma.

Synthesis of the second component of complement by long-term primary cultures of human monocytes

A method has been developed for preparation of confluent monolayers of human monocytes from small volumes of blood and for maintenance of these pure monocyte cultures for up to 16 wk in vitro. These cells phagocytosed 5.7 mum diameter latex beads, rosetted with erythrocytes coated with IgG or with C3, killed Listeria monocytogenes, and synthesized both lysozyme and the second component of complement. Lysozyme was secreted at a rate of approximately 50,000 mol/min per cell for at least 12 wk in cultures. The maximal rate of C2 synthesis and secretion was considerably less; i.e., approximately 30 mol/min per cell between the 2nd and 12th wk in culture. Monocytes produced little C2 during the first 6 days in culture after which a marked increase in the rate of C2 production was noted. This increase was coincident with morphologic evidence of monocyte maturation.

Evaluation ofprimary blood monocyte and bone marrow cell culture for the isolation of Rickettsia rickettsii

Rickettsia rickettsii was isolated from experimentally infected guinea pigs by culture of blood monocytes and bone marrow cells, and from experimentally infected rhesus monkeys by blood monocyte culture. Rickettsiae were identified in monocyte-macrophage monolayers stained by Giménez or flourescent antibody techniques. A total of 78 culture attempts were made from 20 guinea pigs and 16 monkeys. The success of isolation of R. rickettsii in culture was positively correlated with the numbers of rickettsiae present in the blood and bone marrow. in cultures derived from infected guinea pigs, rickettsiae were usually observed after 5 to 7 days of culture, and in monkeys monocyte cultures they were usually observed within 3 to 5 days. Positive cultures were derived from guinea pigs and monkeys as early as the first day of fever and 1 to 3 days before the appearance of other clinical signs. Monocyte cultures became negative with the resolution of rickettsemia and concomitantly with the appearance of serum antibody. Monocyte culture isolation of R. rickettsii may be as sensitive for the detection of rickettsiae in blood and marrow as the intraperitoneal inoculation of guinea pigs or the plaque assay technique. Because of the simplicity of the method and because rickettsiae were often identified within 3 to 5 days after initiation, the monocyte culture technique may be useful in the early diagnois of human rickettsial disease.

Antigens of the Kell blood group system on neutrophils and monocytes: their relation to chronic granulomatous disease

KX, an antigen related to the Kell blood group system, is present in trace amounts on normal red cells and is strongly active on the neutrophils of all of 50 persons thus far tested. Normal circulating monocytes are now shown to also bear KX determinants. Absence of neutrophil KX has been associated with all of three previously tested patients with chronic granulomatous disease. In this study two male siblings with CGD also have been shown to have KX negative leukocytes, and white blood cells from their heterozygous mother were found to have a reduced competency to absorb anti-KX. Five CGD boys are known to lack KX; the probability of this occurring by chance is greater 10(-6).