| 1. |
- Ramos, O F, et al.
(author)
-
Alternative pathway of complement activation by stimulated T lymphocytes. II. Elevation of cytotoxic potential against complement receptor-carrying cell lines.
- 1987
-
In: European Journal of Immunology. - : Wiley. - 0014-2980 .- 1521-4141. ; 17:7, s. 975-979
-
Journal article (peer-reviewed)abstract
- Exposure of lectin-stimulated (concanavalin A, phytohemagglutinin and pokeweed mitogen) blood lymphocytes to human serum or to purified C3 increased their cytotoxic capacity towards complement receptor positive targets such as Raji and Daudi cells. The lysis of complement receptor-negative lymphoblastoid cell lines was not influenced. The lytic capacity of lymphocytes exposed to 12-O-tetradecanoylphorbol 13-acetate was not elevated by human serum. Lectin-stimulated lymphocytes were previously shown to activate and bind C3. The results using lymphocytes activated in different ways and targets with or without complement receptor expression suggest that the C3b deposited on lymphocytes binds to the complement receptor on the targets. This contact elevates the avidity between the two cells as indicated also by the increased frequency of the lymphocyte-target conjugates. On the basis of immune adherence the C3 fragment bound on the lymphocytes was identified as C3b. The increase of the conjugate formation and cytotoxicity was abrogated when the target cells, Raji, were pre-exposed to purified C3d which occupy the CR2 receptor. The majority of lymphocytes responsible for the cytotoxicity were CD8+.
|
|
| 2. |
- Yefenof, E, et al.
(author)
-
Ligands of CR2 do not interfere with C3 fragment fixation or enhanced NK sensitivity of Raji cells treated with human serum.
- 1989
-
In: Immunology Letters. - 0165-2478 .- 1879-0542. ; 21:4, s. 303-306
-
Journal article (peer-reviewed)abstract
- Raji cells activate the alternative complement pathway (ACP) and fix C3 fragments when incubated in human serum (HS). Earlier experiments have shown that CR2 molecules are involved in this phenomenon and the opsonized cells have elevated sensitivity to the lytic effect of CR3-bearing NK cells. We show here that Raji cells treated with CR2 site-specific ligands, (C3d, OKB-7 and HB-5 mAbs, and a synthetic peptide which binds to CR2) generated and bound C3 fragments after exposure to HS. The elevated lytic sensitivity of HS-treated cells was not altered by the presence of the various CR2 ligands. Thus, the membrane-bound C3 fragments are not fixed at the C3dg receptor binding site.
|
|
| 3. |
- Zoback, Mary Lou, et al.
(author)
-
Global patterns of tectonic stress
- 1989
-
In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 341:6240, s. 291-298
-
Research review (peer-reviewed)abstract
- Regional patterns of present-day tectonic stress can be used to evaluate the forces acting on the lithosphere and to investigate intraplate seismicity. Most intraplate regions are characterized by a compressional stress regime; extension is limited almost entirely to thermally uplifted regions. In several plates the maximum horizontal stress is subparallel to the direction of absolute plate motion, suggesting that the forces driving the plates also dominate the stress distribution in the plate interior.
|
|
