1.
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.
2.
Bjursten, Lars Magnus, et al.
(författare)
The kinetics of leucocyte migration into rabbit knee joints elicited by preformed immune complexes with different in vitro characteristics
1983
Ingår i: Immunology. - 0019-2805. ; 49:2, s. 205-213
Tidskriftsartikel (refereegranskat) abstract
Immune complexes were formed in vitro with antibodies obtained from rabbits immunized with bovine serum albumin in Freund's complete (FCA) or incomplete (FIA) adjuvant. The antibodies were mixed with different amounts of antigen. Immune complexes formed at maximum precipitation proportions were efficient in complement activation, whereas immune complexes formed at antigen excess had weak complement-activating properties. When injected into rabbit knee joints, the immune complexes formed at maximum precipitation proportions with FCA or FIA antibodies caused a moderate leucocyte migration into the joints with maximum cell counts 6-8 hr after injection. Injection into the joints of immune complexes formed with FCA antibodies at antigen excess induced a pronounced leucocyte migration with maximum numbers 18 hr after injection. Immunofluorescent studies indicated that these immune complexes became associated with the leucocyte membrane, whereas immune complexes formed at maximum precipitation proportions were found in the leucocyte granulae, indicating that only the complement-activating immune complexes were efficiently eliminated.
3.
Björck, Lars, et al.
(författare)
On the interaction between beta 2-microglobulin and group A streptococci
1984
Ingår i: Scandinavian Journal of Immunology. - : Wiley. - 1365-3083 .- 0300-9475. ; 20:1, s. 69-79
Tidskriftsartikel (refereegranskat) abstract
beta 2-microglobulin (beta 2m) was found to interact with many group A streptococcal strains. The interaction appeared to require multipoint attachment, since monomeric beta 2m in solution showed no binding, whereas both beta 2m monomers bound to liposomes, and beta 2m in aggregates showed affinity for the bacteria. Aggregated HLA antigens (-A, -B and -C) and aggregated beta 2m exhibited the same binding patterns when tested in binding experiments with various group A streptococcal strains. Furthermore, beta 2m aggregates in excess completely blocked the binding of aggregated HLA antigens, thereby demonstrating that beta 2m is able to interact with streptococcal surface structures also when it is part of the HLA antigen complex. M protein-positive group A streptococcal strains bound significantly more beta 2m than M protein-negative variants of these strains. Purified M 12 protein partly inhibited the binding of radiolabelled beta 2m aggregates to whole streptococci, and in gel filtration and affinity chromatography experiments, the M 12 protein interacted with beta 2m. These various data suggest that the interaction between beta 2m and group A streptococci could be mediated by M protein. Lipoteichoic acid (LTA) is a constituent of the streptococcal cell wall that has been reported to form complexes with M protein at the bacterial cell surface. However, LTA did not influence the interaction between beta 2m and streptococci, suggesting that the binding of beta 2m to streptococcal M protein represents a pure protein-protein interaction. In vivo such an interaction could be established between infecting streptococci and host cells. Among 45 strains of different M types large differences in beta 2m binding were recorded, whereas among 60 strains of the classical nephritogenic M types 12 and 49, all were highly beta 2m-reactive, which points towards a role for beta 2m in streptococcal pathogenicity.
4.
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.
5.
Gullberg, Martin, 1955-
(författare)
Recognition requirements and regulatory events directing T cell responses
1983
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
The present study has considered cellular and molecular requirements in T cell responses. The central role of T cell growth factors (TCGF) in T cell responses prompted us to study the regulatory events directing TCGF production in lectin stimulated cultures. It was found that normal spleen cells, activated with Concanavalin A for 24 h, develop suppressive cells that block de novo TCGF production by fresh spleen cells. The induction time for effector suppressor cells (nonadherent, Lyt-2-positive T cells) was found to be 18 h and to parallel the termination of TCGF production in situ. The suppressive mechanism is neither iji situ absorption of TCGF produced at control rates nor killing of TCGF producing cells. These results suggest that suppression of TCGF production is an active process which directly and reversibly blocks TCGF-producing cells.This study also indicated that ConA induced a very limited proliferation of Lyt-2- T helper cells (TH) in unselected T cell populations. The activation and growth requirements of Lyt-1+ TH cells were directly investigated and compared with those of Lyt-2+ cytotoxic T lymphocytes (CTL), as defined by the selective expression of Lyt differentiation antigens and functional activities. This analysis revealed a profound difference in activation and growth requirements between these T cell subsets. Thus, while Lyt-2+ CTL precursors can be induced to TCGF reactivity by soluble lectins, in the absence of specialized accessory cells,; Lyt-2" TH cell precursors show a strict accessory cell requirement both for activation and proliteration. Finally, the low level of TH cell effector function, detected in a primary responses to allo-MHC-antigens or lectins, appears to be due to the development of suppressive Lyt2+ T cells.The functional relevance of Lyt-2 antigens expressed on CTL membranes was further assessed in the last part of this study. Two distinct activation systems were used, namely MHC-antigens, provided as UV-irradiated stimulator cells or polyclonal induction by a 4 h pulse, with lectins. Both procedures were shown to selectively induce Lyt-2+ CTL precursors into TCGF reactivity without leading to mitosis, unless TCGF was added. In both cases it was found that monoclonal anti-Lyt-2 antibodies inhibited the two antigen- dependent phases of CTL responses namely, the initial induction step and target cytolysis. The analogy observed between antigen specific and lectin mediated indueton and target cytolysis, with regard to the susceptibility of inhibition by anti-Lyt-2 antibodies has lead to a general hypothesis on CTL activation.
6.
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.
7.
8.
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.
9.
10.
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.
