1.
Peetre, Christina, et al.
(författare)
A tumor necrosis factor binding protein is present in human biological fluids
1988
Ingår i: European Journal of Haematology. - : Wiley. - 0902-4441 .- 1600-0609. ; 41:5, s. 414-419
Tidskriftsartikel (refereegranskat) abstract
Tumor necrosis factor (TNF) possesses both beneficial and toxic bioactivities. Mechanisms may operate to counteract harmful effects. We have identified a TNF binding protein (TNF-BP), which shows increased levels in serum and urine of patients on regular hemodialysis treatment (RDT). TNF-BP inhibited the specific binding of human recombinant TNF (rTNF) to its cell surface receptor. Results from gel chromatography demonstrated the presence in serum and urine of a macromolecule with an apparent molecular weight of 50,000, which formed a complex with rTNF. A 62-fold purification of TNF-BP from urine of patients on RDT was achieved by ion exchange chromatography and gel chromatography. Partially purified TNF-BP reduced the growth inhibitory effect of rTNF on a susceptible leukemia cell line. TNF-BP may act as a regulator of the biological activity of TNF and could have beneficial effects in certain inflammatory conditions.
2.
Truedsson, L, et al.
(författare)
Protein HC-IgA complexes carry antibody activities
1988
Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 27:2, s. 201-208
Tidskriftsartikel (refereegranskat) abstract
Polyclonal protein HC-IgA complexes (HC-IgA) were isolated from two different serum pools. Their hydrodynamic volumes were found to be slightly greater than that of monomeric IgA but less than that of dimeric IgA. Sodium dodecyl sulphate (SDS)-polyacrylamide gel electrophoresis of reduced and carboxymethylated complexes followed by immunoblotting showed that the complexes contained normal light and heavy Ig chains, and one polypeptide chain with Mr = 90,000, which carried both IgA alpha chain and protein HC epitopes. Enzyme-linked immunosorbent assays (ELISA) demonstrated that the isolated HC-IgA carried about 0.1 and 4%, respectively, of the antibody activities against one carbohydrate antigen (Yersinia enterocolitica serotype 0:3 lipopolysaccharide) and one protein antigen (rabbit IgG, i.e. antigen for rheumatoid factors) of the IgA populations of the two serum pools. HC-IgA with rheumatoid factor activity could also be demonstrated in the unfractionated serum pool. The binding of HC-IgA in the ELISA was not mediated through its protein HC part. The present observations show that HC-IgA carries antibody activities and constitutes a unique class of IgA complexes, since it does not dissociate under denaturating conditions after reduction. It may represent a further biological potential of the humoral immune system.
3.
4.
Braide, M, et al.
(författare)
Optimized density gradient separation of leukocyte fractions from whole blood by adjustment of osmolarity
1986
Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 1872-7905 .- 0022-1759. ; 93:2, s. 183-191
Tidskriftsartikel (refereegranskat) abstract
Some of the compounds used for density gradient separation of blood cells have high osmolarities at the concentrations needed to create the required specific densities. Several mixed media use a combination of hyperosmolar shrinkage and red cell aggregation to improve cell separation. Due to the characteristics of Percoll density gradient medium the density and osmolarity of the gradient can be controlled separately. In the present study, Percoll gradients were used to determine the buoyant densities of different human blood cells at the osmolarities 300 mosM, 350 mosM and 400 mosM. Cell volumes were measured at the same osmolarities using a Coulter counter with channelyzer. As expected, the cell buoyant densities increased and the cell volumes decreased at the higher osmolarities used. There were, however, quantitative differences between the cells with respect to the effects of an increased osmolarity, making a 350 mosM density gradient the most effective in separating mononuclear leukocytes from polymorphonuclear leukocytes. A 400 mosM gradient offered the best possibilities to separate red blood cells from polymorphonuclear leukocytes. A one-step centrifugation procedure, based on these principles, is presented. This procedure makes possible the simultaneous purification of mononuclear leukocytes and polymorphonuclear leukocytes, suitable for functional assays.
5.
Christensson, B, et al.
(författare)
Imbalanced serum IgG subclass pattern in toxic shock syndrome patients: deficiency of specific IgG1 and IgG4 subclass antibodies to toxic shock syndrome toxin 1
1986
Ingår i: Clinical and Experimental Immunology. - 0009-9104. ; 66:2, s. 443-449
Tidskriftsartikel (refereegranskat) abstract
An imbalanced serum IgG subclass pattern was identified in 10 patients with toxic shock syndrome (TSS) showing remarkably low subclass levels of various combinations. IgG2 levels were significantly reduced as compared to normal controls. The IgG subclass-specificity of antibodies to toxic shock syndrome toxin (TSST-1) was investigated by a solid-phase radioimmunoassay. TSS-patients lacked pre-immunity to TSST-1 in all four IgG subclasses. Normally acquired immunity to the toxin as well as the serological response developing in two patients with TSS was generally restricted to IgG1 and IgG4. A strong booster response of all four IgG subclasses was seen in three patients with S. aureus septicaemia due to TSST-1 producing strains. The lack of specific IgG1 and IgG4 antibodies to TSST-1 and the low serum IgG subclass levels found in the TSS-patients could be of pathogenetic significance and help to explain the susceptibility to TSS in certain individuals.
6.
Fernandez-Luna, J L, et al.
(författare)
A sensitive and rapid enzyme-linked immunosorbent assay using monoclonal antibodies for simultaneous quantitation of free and IgA-complexed protein HC
1985
Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 0022-1759. ; 82:1, s. 101-110
Tidskriftsartikel (refereegranskat) abstract
A sensitive and rapid enzyme-linked immunosorbent assay for simultaneous quantitation of free and IgA-complexed human protein HC was developed with monoclonal murine antibodies. The total amount of protein HC (free plus IgA-complexed) was measured by a competitive procedure while the protein HC-IgA complex was quantitated by a sandwich enzyme immunoassay. The amount of free protein HC was then obtained as the difference between the 2 measured values. The sensitivity of the procedure was 70 micrograms/1 for the total amount of protein HC and 80 micrograms/1 for the protein HC-IgA complex. At ordinary human serum levels of free protein HC and protein HC-IgA complexes the coefficient of variation for the procedure was about 5%. One worker could determine the concentrations of free and IgA-complexed protein HC in up to 400 serum samples in a working day.
7.
Fredrikson, G, et al.
(författare)
Use of protein G for preparation and characterization of rabbit antibodies against rat adipose tissue hormone-sensitive lipase
1987
Ingår i: Journal of Immunological Methods. - : Elsevier BV. - 0022-1759. ; 97:1, s. 65-70
Tidskriftsartikel (refereegranskat) abstract
The newly described immunoglobulin G-binding streptococcal surface protein, protein G, was used to prepare and characterize rabbit antibodies. The antibodies were directed against rat hormone-sensitive lipase, the rate-limiting enzyme in the hydrolysis of the triacylglycerols stored in adipose tissue. Antiserum was obtained after two injections with 20 micrograms enzyme protein, and the immunoglobulin fraction was obtained using a protein G-based solid-phase radioimmunoassay. The hydrolysis of acylglycerols by the enzyme was inhibited by the antibodies, and the enzyme could be efficiently removed from a solution using the antibodies and heat-killed streptococci expressing surface protein G. By Western blot and detection with 125I-protein G, the antibodies were found to selectively bind to hormone-sensitive lipase and to a smaller extent to two minor contaminants, possibly proteolytic fragments of the lipase. The amount of 125I-labelled protein G bound to the lipase on the blot was quantitatively related to the amount of enzyme protein down to the detection limit 10 ng.
8.
Hedlund, G, et al.
(författare)
Maximal interferon-gamma production and early synthesis of interleukin-2 by CD4+ CDw29- CD45R- p80- human T lymphocytes.
1989
Ingår i: Immunology. - 0019-2805. ; 66:1, s. 49-53
Tidskriftsartikel (refereegranskat) abstract
Functionally distinct subsets within the T-helper (CD4+) cell population have been described in man, rat and mouse. We have shown previously that the CD4+ 45R- human lymphocytes are producers of IL-2 within 24 hr of polyclonal stimulation and are the major interferon (IFN) producers. The mAbs 4B4 (CDw29) and Leu 8 (p80) are here used together with Leu-18 (CD45R) to characterize the subpopulations of the CD4+ human lymphocytes in more detail. The majority of the CD45R+ cells were CDw29- and the majority of the CDw29+ cells were CD45R-. Most of the CD45R+ cells (78%) were also p80+. A significant number of cells (12%) were CDw29- CD45R-. The predominant subpopulations were defined to be CDw29- CD45R+ p80+ (31%), CDw29+ CD45R- p80- (24%) and CDW29+ CD45R- p80+ (18%). Within the CD4+ CD45R- subpopulation different subsets vary in their capacities to produce IFN and to produce IL-2 within 24 hr after activation. CD4+ CDw29- CD45R- p80- T lymphocytes produced the largest quantities of IFN and IL-2.
9.
Johansson, Hugo, et al.
(författare)
Herpes simplex type 1-induced Fc receptor binds to the Cgamma2-Cgamma3 interface region of IgG in the area that binds staphylococcal protein A
1989
Ingår i: Immunology. - 0019-2805. ; 66:1, s. 8-13
Tidskriftsartikel (refereegranskat) abstract
The binding site of immunoglobulin G (IgG) to herpes simplex virus (HSV) type 1-induced Fc receptor was investigated using human IgG Fc intermediate (Fc(i)) fragments, fragment D of staphylococcal protein A (SPA) and chemically modified human IgG. Human IgG Fc(i) fragment composed of one Cgamma2 and two Cgamma3 domains, bound strongly to HSV-1-infected cells. Fragment D, a monovalent subunit of SPA, inhibited the binding of radiolabelled human IgG Fc fragments to the HSV Fc receptor. Reductively methylated human IgG reacted equally well to HSV-infected cells, as did chemically unmodified IgG in contrast to N-acetylimidazole-modified and diethylpyrocarbonate-modifed human IgG, which were unreactive. These results suggest a similar binding site on human IgG for SPA and the HSV-1 Fc receptor with involvement of the amino acid residues Tyr and His but not Lys. The similarities of binding sites on the IgG molecule for the HSV-1 Fc receptor and rheumatoid factors (RF) may be important for understanding the mechanism of RF production in rheumatoid arthritis or other disease states.
10.
Johansson, Hugo, et al.
(författare)
Interaction between herpes simplex type 1-induced Fc receptor and human and rabbit immunoglobulin G (IgG) domains
1986
Ingår i: Immunology. - 0019-2805. ; 58:2, s. 251-255
Tidskriftsartikel (refereegranskat) abstract
Cells infected with herpes simplex virus type 1 (HSV-1) express a cell surface receptor able to bind to the Fc region of immunoglobulin G (IgG). The ability of HSV-1-infected cells to bind 125I-labelled human and rabbit IgG and IgG fragments was studied to localize the site of interaction to the C gamma 2 or C gamma 3 domains of IgG. 125I-labelled IgG and IgG Fc fragments consisting of C gamma 2 and C gamma 3 domains bound strongly to HSV-infected cells and did not bind to uninfected cells. In contrast, 125I-labelled F(ab')2, Facb [consisting of F(ab')2 and C gamma 2 domains] and pFc' (consisting of C gamma 3 domains) fragments did not bind to any of these cells. Unlabelled IgG and IgG Fc fragments inhibited the interaction between 125I-labelled rabbit IgG Fc and the HSV Fc receptor, whereas F(ab')2, Facb and pFc' fragments failed to inhibit this interaction. These data indicate that the HSV Fc receptor requires both the C gamma 2 and C gamma 3 domains for interaction with the IgG molecule analogous to the known interaction of protein A of Staphylococcus aureus, the Fc binding proteins of Group A, C and G streptococci, and certain human rheumatoid factors.
