A 48-well micro chemotaxis assembly for rapid and accurate measurement of leukocyte migration

We designed a 48-well chemotaxis chamber to minimize manipulation time and amount of material required by the larger blindwell or Boyden chemotaxis chamber. Cell and chemoattractant dose-response curves showed that results were comparable to our better than those obtained with blindwell chambers. The volume of chemoattractant per well is 25 microliter; the number of cells can be as low as 10,000. The time needed for setting up this multiwell unit and for staining the membrane filter sheet is negligible. Combined with the use of an image analyzer to count the number of migrated cells, the method is suitable for clinical research on the functional state of monocytes in large groups of patients.

Rapid quantitation of neutrophil chemotaxis: use of a polyvinylpyrrolidone-free polycarbonate membrane in a multiwell assembly

A neutrophil chemotaxis assay was developd which permits rapid, quantitative assessment of migration across a membrane filter. The critical factor in the assay was the use of a 10 microns thick polycarbonate membrane without the usual polyvinylpyrrolidone coating. Migrated neutrophils remain adherent to the uncoated membrane, whereas 20-50% fall off polyvinylpyrrolidone-coated membranes. A major advantage of the method is that neutrophil chemotaxis can be readily quantified, since the migrated cells adhere to the membrane surface and are in one optical plane for counting. A 25 mm x 80 mm membrane sheet was used in a 48-well micro chemotaxis assembly, which requires only 20,000 neutrophils and 25 microliters of attractant per assay well. Neutrophil chemotaxis was complete within 10-20 min at 37 degrees C, with 20-30% of the cells migrating to N-formyl-methionyl-leucyl-phenylalanine and 40-50% migrating to complement derived C5a.

Simultaneous generation of tuberculin-type and cutaneous basophilic hypersensitivity at separate sites in the guinea pig

Strain-2 guinea pigs received two separate intradermal immunizations. The first was a mixture of living BCG (Phipps strain of bacille Calmette-Guerin) and syngeneic line-10 hepatoma cells. The second, administered after 6 weeks or more, was keyhole limpet hemocyanin (KLH) in saline. One week after the second injection, the animals were skin tested at separate sites with tumor cells, purified protein derivative of tuberculin (PPD) and KLH. Delayed cutaneous hypersensitivity (DCH) reactions were evident by 24 h. At this time the reaction sites were processed by histological methods that preserved basophil morphology and staining qualities. Three distinctive infiltrates were elicited by the different antigens. In addition to the mononuclear cell infiltrate common to all three reactions, the KLH site had a high concentration of basophils and few neutrophils, characteristic of cutaneous basophilic hypersensitivity (CBH); the PPD site had practically no basophils but many neutrophils; and the tumor cell reaction was predominantly mononuclear, with small numbers of basophils and virtually no neutrophils. Simultaneous generation of different DCH reactions in the same animal and quantitative description of the cellular infiltrate provided a basis for DCH classifications, with KLH CBH and tuberculin reactions as standards for comparison. Since challenge with three antigens at separate sites in the same animal generated DCH reactions with widely differing patterns of cellular infiltration, the reason for the differences must occur at the local sites or, if circulating, must be antigen-specific.

A human serum protein system affecting muscle contractility: characterization of the five components and their reaction sequence

A human serum protein system that affects muscle contractility, previously reported to be a calcium transport system (CTS), was fractionated into five protein components, A, B1, Bfi, B3 and C. The system was assayed on frog heart muscle in vitro by its capacity to increase contractile force and at high concentrations to cause contracture. With separated fractions, the reaction sequence was divided into three separate steps: B1 and B3 interacted with the heart in the first step, B2 and B3 in the second, and A and C in the third. Increased contractility occurred only after the third step. Partial purification, with preservation of biological activity, was achieved for B1, B2, A and C. B1 has a M.W. of about 170,000, as determined by its elution from Sephadex G-200. B2, a labile protein of M.W. 220,000, was one of the few serum proteins precipitated by M.W. 5000,000 dextran sulfate at pH 8.0. This was the basis for the preparation of highly purified B2, which was used to produce rabbit anti-B2 antibody. Experiments with this antibody proved that B2 became bound to the heart surface. CTS-A, the smallest protein of the system, had a M.W. of approximately 130,000. The M.W. of C was over 300,000. Purified C antigen induced rabbit antibody that inhibited the action of C without affecting the other components.

Characterization of macrophage chemotaxins in tumor cell cultures and comparison with lymphocyte-derived chemotactic factors

Culture fluids from five murine sarcomas were chemotactic for syngeneic peritoneal macrophages in vitro. Peritoneal macrophages from mice infected with Mycobacterium bovis, strain Bacillus Calmette-Guérin, were more responsive to the chemotactic factor in tumor cultures than were normal macrophages. Peritoneal granulocytes, however, did not significantly respond to this factor. The level of chemotactic activity in tumor cultures paralleled cell growth for all five tumors; maximal levels occurred during log growth. Culture medium alone or fluids from proliferating spleen cell cultures stimulated with mitogens did not have detectable chemotactic activity. Chromatography of the tumor culture fluids resulted in a single peak of chemotactic activity in the 15,000-molecular weight range on Sephadex G-100 and at about 7.5 mmho/cm specific conductance on diethylaminoethyl cellulose. By both biological and physicochemical characteristics, the chemotactic activity in tumor culture fluids was different from mouse lymphocyte-derived chemotactic factor.

Histamine-induced inhibition of normal human basophil chemotaxis to C5a

Histamine in concentrations as low as 10(-8) M inhibited the chemotactic response of normal human basophils to C5a. Histamine had no effect on basophil chemotaxis to lymphocyte-derived chemotactic factor. Histamine inhibition of basophil chemotaxis to C5a was prevented by metiamide, a drug which blocks H2 receptors for histamine. Since the accumulation of basophils in delayed cutaneous basophilic hypersensitivity (CBH) reactions may occur in part because of chemotaxis to C5a, and since C5a can induce histamine release, histamine inhibition of chemotaxis may limit basophil infiltration in CBH lesions.

Suppression of tumor growth in strain 2 guinea pigs by xenogeneic antitumor antibody

Line 10 hepatoma cells were incubated with antiserum specific against line 10 cells (RaL10) and then tested for growth in syngeneic Wright strain 2 guinea pigs. Palpable tumors appeared in only 11 of 23 animals inoculated id with 10(5) RaL10-treated tumor cells, compared with an incidence of 21 of 23 for nonimmune rabbit serum (NRS)-treated cells and 23 of 23 for cells treated with syngeneic guinea pig serum. Animals inoculated with RaL10-treated tumor cells did not develop systemic tumor immunity. The long-term survival of guinea pigs receiving RaL10-treated tumor cells iv was 6 of 12 with a dose of 10(5) cells and 8 of 11 with 10(4) cells. None of the animals receiving 10(4) or 10(5) control tumor cells treated with NRS survived. RaL10 antiserum was not toxic to line 10 tumor cells in vitro, but mediated tumor-specific cytolytic reactions in the presence of fresh guinea pig serum or on the addition of peritoneal exudate cells from nonimmunized syngeneic guinea pigs.

Chemotactic responses of normal human basophils to C5a and to lymphocyte-derived chemotactic factor

Peripheral blood basophils from normal human subjects responded chemotactically to the complement component C5a and also to the supernatant fluid from cultured human lymphocytes stimulated by mitogens or specific antigen. Basophil chemotactic factor (BCF) was detected in stimulated lymphocyte cultures within 24 hr and increased for the first 3 days. BCF was found after stimulation of lymphocytes by B or T cell mitogens as well as by specific antigen. The amount of BCF in culture fluids was independent of cell proliferation. Monocyte chemotactic factor (MCF) and BCF could not be separated from one another by Sephadex or DEAE chromatography. Both activities were eluted from Sephadex G-100 columns in a m.w. region of about 15,000 daltons and were found after ion exchange chromatography on DEAE in a peak eluted by 0.1 M NaCl. These findings suggest that mitogen or antigen-stimulated lymphocytes secrete a molecule that is chemotactic for both monocytes and basophils. Thus, in the absence of a basophil-specific chemotactic molecule, the preferential accumulation of basophils in certain types of delayed hypersensitivity skin reactions must be due to additional factors such as basophil chemotaxis augmentation factor.

Mouse lymphotoxin

The addition of PHA to C3H mouse spleen cells in tissue culture led to the production of lymphotoxin (LT). Cytotoxicity was assayed by addition of the culture fluids to syngeneic target cells labeled with tritiated thymidine; after an incubation period of 72 hr the amount of radioactivity released into the supernatant was measured. The LT activity in unfractionated culture fluids survived lyophilization, remained unchanged for many weeks at 4 degrees C, and progressively decreased on heating at 56 degrees C for periods from 1 to 9 hr. Based on the G-200 Sephadex distribution coefficients for several preparations, the m.w. of mouse lymphotoxin was about 41,000 daltons. Lymphotoxin from three different spleen cell production runs was recovered from isoelectric focusing columns in sharply focused peaks, the pH of which ranged from 4.4 to 4.8.

A method for staining multiple chemotaxis filters

A device is described which holds chemotaxis filters on glass slides so that the cells on as many as 128 filters can be stained simultaneously. The procedure for using the batch stainer with Wright's stain is outlined.

Extraction of tumor-specific antigen from cells and plasma membranes of line-10 hepatoma

Tumor-specific antigen was extracted with 3 M KCl from line-10 guinea pig hepatoma cells. The yield of antigenic activity, estimated by production of delayed cutaneous hypersensitivity reactions in line-10 immune guinea pigs, was 10-30% of the antigen present in intact cells. By ultracentrifugation criteria, the extracted antigen was soluble. Gel filtration, ion exchange chromatography, and salting-out studies showed that the antigen was heterogeneous in size and net charge. The possibility that 3 M KCl extracted a homogeneous population of molecules associating into polymers of various sizes at low ionic strength was ruled out by heterogeneity on Sephadex G-200 chromatography at high ionic strength. After osmotic lysis of sucrose-loaded line-10 cells, whole plasma membranes or large membrane fragments were obtained in a yield of about 20%. The isolation procedure did not cause detectable loss of membrane antigenic activity. The membranes had 33 skin test U/mg membrane protein, compared to the intact cell value of 1.7 skin test U/mg cell protein. Extracts of plasma membranes had 10-20% of the antigenic activity of the starting membrane material. In contrast to the wide variety of proteins liberated from intact cells, much of the protein extracted from the membranes was in the molecular weight range above 250,000.

Protective tumor immunity induced by potassium chloride extracts of guinea pig hepatomas

Tumor-specific antigens of cells of the diethylnitrosamine-induced hepatomas in strain-2 guinea pigs were extracted with 3 M KCl. Immunization of normal animals with the extracted tumor antigens in adjuvant protected them against a subsequent challenge with viable tumor cells. Extracted tumor-specific antigens were less effective immunogens than viable tumor cells for both of two antigenically distinct lines.

Interaction of BCG-activated macrophages with neoplastic and nonneoplastic cell lines in vitro : quantitation of the cytotoxic reaction by release of tritiated thymidine from prelabeled target cells

Peritoneal cells from mice infected ip with Mycobacterium bovis, strain BCG, were cytotoxic to syngeneic tumor cells in vitro. Cytotoxicity was estimated by measurement of release of tritiated-thymidine (3-H-TDR) from prelabeled target cells. The cell responsible for tumor cytotoxicity was the macrophage. Macrophages from uninfected mice or from oil-, starch-, or thioglycollate-induced peritoneal exudates had little effect on labeled tumor monolayers. Tumoricidal macrophages were present at 3-7 days and persisted through 6 weeks after a single BCG injection. Two neoplastic/nonneoplastic cell-line pairs, all four of the cell lines derived from a cloned syngeneic embryo cell line, were used as target cells for BCG-activated macrophages. Both tumor cell lines released significantly more 3-H-TDR than did the two nonneoplastic lines. In a mixed neoplastic/nonneoplastic target cell population, BCG-activated macrophages selectively destroyed the neoplastic cells; nonneoplastic cells were not affected as "innocent bystanders".