| 1. |
- Forsgren, A, et al.
(författare)
-
Bacteria-immunoglobulin-lymphocyte interactions--new aspects
- 1980
-
Ingår i: Scandinavian Journal of Infectious Diseases. Supplementum. - 0300-8878. ; Suppl 24, s. 8-112
-
Tidskriftsartikel (refereegranskat)abstract
- Of 30 bacterial species tested 18 stimulated DNA synthesis in human blood lymphocytes. The maximum response was after 3-4 days of culture suggesting a mitogenic effect. This was confirmed by the induction of polyclonal antibody production shown by a plaque assay. Most bacterial species increased the DNA synthesis in B-enriched lymphocytes and unseparated lymphocytes but had negligible activity on T-enriched lymphocytes. Among bacteria with a mitogenic effect and ability to induce polyclonal antibody production are Staphylococcus aureus, Haemophilus influenzae, Mycobacterium tuberculosis, Neisseria gonorrhoeae, Streptococcus group A and Streptococcus pneumoniae. In an attempt to define structure (s) on the B-lymphocyte surface responsible for the lymphocyte stimulation the binding of IgD, IgM, and HLA-A, -B and HLA-D antigens to different bacterial species was investigated. A high IgD binding to N. catarrhalis and H. influenzae and a moderate binding of IgD to streptococci was found. Binding studies employing radiolabelled IgD Fab- and Fc-fragments indicated that the binding probably involves the CHl-region of the IgD molecule. Three purified radiolabelled myeloma IgM M-components were all shown to be efficiently bound to many bacteria indicating that a part of the IgM molecule other than the antigen-combining site can be involved in attachment to bacteria. Highly purified detergent-solubilized HLA-A, -B and HLA-D antigens, when separately incorporated into liposomes, were bound efficiently to two strains of N. catarrhalis and to one strain of H. influenzae weakly to one strain of E. coli, but not at all to another strain E. coli. Preliminary experiments indicate that these bacteria-immunoglobulin and bacteria-HLA-antigen interactions lead to lymphocyte stimulation.
|
|
| 2. |
- Hallberg, A, et al.
(författare)
-
Natural killer cell activity and antibody-dependent cellular cytotoxicity in newborn infants
- 1982
-
Ingår i: Acta Paediatrica Scandinavica. - : Wiley. - 0001-656X .- 0803-5253 .- 1651-2227. ; 71:3, s. 431-436
-
Tidskriftsartikel (refereegranskat)abstract
- The ability of lymphocytes from the peripheral blood of preterm and term infants and adult women and men to mediate natural killing (NK) and K cell activity (antibody-dependent cellular cytotoxicity) was analysed in 4 hours 51Cr-release assays. K 562 cells were targets for NK activity. K cell activity was assayed on antibody-coated rat thymocytes. Lymphocytes from adult male donors were significantly more cytotoxic to K 562 cells than were lymphocytes from adult female donors. Lymphocytes from both preterm and term infants had significantly lower NK and K cell activity than lymphocytes from adult donors. During the first month of life no increase in NK activity or K cell activity occurred in 7 infants who were re-examined. It is concluded that neither NK nor K cell activities are fully developed during the first month of life.
|
|
| 3. |
|
|
| 4. |
- Nilsson Ekdahl, Kristina, et al.
(författare)
-
The effect of fructose-2,6-bisphosphate and AMP on the activity of phosphorylated and unphosphorylated fructose-1,6 bisphosphatase from rat liver
- 1984
-
Ingår i: FEBS letters. ; 167:2, s. 203-209
-
Tidskriftsartikel (refereegranskat)abstract
- Rat liver fructose-1,6-bisphosphatase was partially phosphorylated in vitro and separated into unphosphorylated and fully phosphorylated enzyme. The effects of fructose 2,6-bisphosphate and AMP on these two enzyme forms were examined. Unphosphorylated fructose-1,6-bisphosphatase was more easily inhibited by both effectors. Fructose 2,6-bisphosphate affected both K0.5 and Vmax, while the main effect of AMP was to lower Vmax. Fructose 2,6-bisphosphate and AMP together acted synergistically to decrease the activity of fructose-1,6-bisphosphatase, and since unphosphorylated and phosphorylated enzyme forms are affected differently, this might be a way to amplify the effect of phosphorylation.
|
|
| 5. |
- Malmström, P., et al.
(författare)
-
Countercurrent Distribution of Lymphocytes from Human Peripheral Blood in an Aqueous Two-Phase System : I. Separation into Subsets of Lymphocytes Bearing Distinctive Markers’
- 1980
-
Ingår i: Cellular Immunology. - : Elsevier BV. - 0008-8749. ; 53, s. 39-50
-
Tidskriftsartikel (refereegranskat)abstract
- Lymphocytes from human peripheral blood have been separated by countercurrent distribution in a charged aqueous two-phase system composed of Dextran T 500 and polyethylene glycol 6000 with a cell yield of 59–88% and viability above 90%. A highly reproducible partition pattern was seen with four distinct peaks. Lymphocytes with surface membrane immunoglobulin (SmIg) were located in the first part of the distribution corresponding mainly to peak I. T lymphocytes as detected by E rosetting and α-naphthyl acetate esterase (ANAE) staining showed a broad distribution with a maximum in peaks II and III. ANAE-negative lymphocytes were seen in both extremes of the distribution, corresponding to B cells in the first part and to a population of E− and SmIg− lymphocytes in the last part. Monocytes were present in all fractions with some enrichment in peaks II–IV. Lymphocytes with low-affinity Fc receptors were found in B-cell-containing fractions in the first part of the distribution, but also in the last part. Lymphocytes with high-affinity Fc receptors were detected mainly in peak IV. It is thus demonstrated that peripheral blood lymphocytes can be fractionated into subpopulations enriched in cells with characteristic markers.markers.
|
|
| 6. |
- Malmström, P, et al.
(författare)
-
Countercurrent distribution of lymphocytes from human peripheral blood in an aqueous two-phase system. : II. Separation into subsets of lymphocytes with distinctive functions
- 1980
-
Ingår i: Cellular Immunology. - : Elsevier BV. - 0008-8749. ; 53, s. 51-64
-
Tidskriftsartikel (refereegranskat)abstract
- Lymphocytes from human peripheral blood were separated by Countercurrent distribution (CCD) in a charged aqueous two-phase system composed of Dextran T 500 and polyethylene glycol 6000. Maximal responses to the T-cell mitogens phytohemagglutinin and concanavalin A were detected in a part of the distribution corresponding to the area where the highest percentage of E rosetting cells were seen. Antibody-dependent cellular cytotoxicity was mediated by lymphocytes located in a restricted part of the distribution separate from the majority of T lymphocytes. Lymphocytes with natural killer activity against K 562, adherent melanoma cells, and fibroblasts were detected in the same region. This area of the distribution also contained the peak of lymphocytes with high-affinity Fc receptors. It was further investigated whether affinity separation may be possible in two-phase systems on the basis of cell to cell interaction. Affinity CCD utilizing the interaction between sheep erythrocytes (SRBC) and T lymphocytes was shown to redistribute the majority of T cells into the area in which SRBC were located, while other lymphocytes were not affected. Lymphocytes mediating natural killing to adherent target cells were not redistributed, indicating that they lack high-affinity receptors for SRBC.
|
|
| 7. |
|
|
| 8. |
- Sjögren, H O, et al.
(författare)
-
Column separation of monocytes by adherence to gelatin beads
- 1983
-
Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 0022-1759. ; 56:3, s. 285-294
-
Tidskriftsartikel (refereegranskat)abstract
- This investigation was performed to study whether the efficient binding of collagen to monocytes in the presence of fibronectin and heparin may be used for separation of monocytes from human peripheral blood. It was shown that monocytes adhere selectively to gelatin bead columns in the presence of fresh plasma and heparin. Mononuclear blood cells are rapidly depleted of monocytes by passage through a 5-10 ml column at a flow rate of 1.5-2.0 ml per min. Adhering lymphocytes are more loosely attached and may be detached by stirring and washing, while the monocytes can be eluted by 50 mM EDTA. This separation technique is suitable for combination with various other methods since it is rapid, allows convenient handling of large numbers and yields cells with very high viability. Although most B lymphocytes pass through the column without attaching, there is some enrichment of B cells and non-T, non-B cells among the adherent lymphocytes.
|
|
| 9. |
- Wadsworth, C, et al.
(författare)
-
Spot immunoprecipitate assay in gel compared with immune reactions in solution and applied to antibody titration
- 1983
-
Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 1872-7905 .- 0022-1759. ; 62:2, s. 217-229
-
Tidskriftsartikel (refereegranskat)abstract
- Precipitation profiles of spot immunoprecipitate assay (SIA) reactions in gel are shown to have characteristics analogous to classic precipitin curves representing such immune reactions in solution. Thus SIA profiles of precipitated human albumin (HSA) and anti-HSA as checkerboard analysis permit: (1) determination of optimal proportions of antibody and antigen, (2) titration of antiserum as to antigen-binding capacity and (3) estimation of the concentration of specific antibody in an antiserum. The validity of the method was confirmed by similar results already reported for precipitin analysis of anti-HSA in solution. The stained protein assay method for determination of total protein used for the calculations had a reliable (r = 0.9979) working range for quantification between 0.1 and 0.83 microgram protein in 3 microliters samples (greater than or equal to 0.03 g/l). Study of SIA profiles in the extreme antibody excess region confirmed the validity of SIA quantification. The high sensitivity of SIA as compared with radial immunodiffusion is related to high ratios (8-9) of antibody to antigen; the reliable detection limit for SIA is 10 mg/l in a 3 microliters sample. SIA is easy to perform with simple laboratory equipment, allows measurement of any precipitable antigen with very small amounts of reactants, and gives results within an hour.
|
|
| 10. |
- Nilsson, Rune, et al.
(författare)
-
Antigen-independent binding of rat immunoglobulins in a radioimmunoassay. Solutions to an unusual background problem
- 1984
-
Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 1872-7905 .- 0022-1759. ; 66:1, s. 17-25
-
Tidskriftsartikel (refereegranskat)abstract
- A high non-specific binding of immunoglobulins to plastic surfaces was noted with a number of rat sera, when tested in an indirect 125I-labeled protein-A assay for detection of cell-surface-bound rat immunoglobulins of various classes and IgG subclasses. This type of non-specific binding was found with all types of Ig. The degree of binding varied with the type of test plate used and fluctuated with time among sera drawn sequentially from the same donors. Coating test wells with fetal calf serum supplemented with BSA, gelatin or fibrinogen did not eliminate the reactions. The immunoglobulins bind directly to the polystyrene, and not to antigens present in fetal calf serum or autoantigens in rat serum. Two different approaches were used to eliminate the nonspecific reaction. When living cells were used as target antigens, exclusively cell-bound radioactivity was eluted with the non-ionic detergent Nonidet P40, which solubilizes the cell membrane without breaking the protein-A/rabbit IgG, rabbit IgG/rat Ig, or rat Ig/plastic interactions. When rat serum antibodies are tested on target antigens adsorbed on non-tissue culture grade plates, non-specific binding may be avoided by including 0.05% Tween 20 in the incubation mixture.
|
|
