|
|
||||||||
The Journal of Immunology, Vol 153, Issue 1 262-269, Copyright © 1994 by American Association of Immunologists
ARTICLES |
RM Jack, BA Lowenstein and A Nicholson-Weller
Department of Rheumatology and Immunology, Brigham and Women's Hospital, Boston, MA.
The C1q receptor (C1qR) is expressed on a variety of cells, including polymorphonuclear leukocytes (PMN), in which stimulation by the C1qR leads to activation as measured by superoxide production. To investigate the expression and modulation of the C1qR on PMN, the binding of biotinylated C1q to PMN in suspension was measured by flow cytometry. Biotinylated C1q bound in a saturable and specific manner to PMN and the use of low ionic strength buffers enhanced binding. Covalent coupling of C1q to Sepharose beads allowed the affinity precipitation of a single 125-kDa band from surface iodinated PMN. The apparent molecular mass of the C1qR increased to 135 kDa upon reduction. Freshly isolated PMN had a uniform expression of C1qRs and phorbol myristate acetate induced a unimodal up-regulation of receptors. The inflammatory peptide FMLP rapidly up-regulated receptors by up to fivefold, and the high level of expression remained constant over 45 min. Taxol inhibited the FMLP induction of C1qR up-regulation, indicating that the ability to move the intracellular stores of C1qR depends on normal microtubule functioning. Thus, the C1qR is a constitutively expressed protein of the human PMN plasma membrane and it is rapidly up-regulated from a discrete intracellular pool of preformed molecules with the same kinetics as CR1 and CR3. It is likely that the C1qR is a component of the PMN complement receptor exocytic vesicle (CREV), in which CR1 and CR3 are also stored.
This article has been cited by other articles:
![]() |
C. A. Ogden, A. deCathelineau, P. R. Hoffmann, D. Bratton, B. Ghebrehiwet, V. A. Fadok, and P. M. Henson C1q and Mannose Binding Lectin Engagement of Cell Surface Calreticulin and CD91 Initiates Macropinocytosis and Uptake of Apoptotic Cells J. Exp. Med., September 17, 2001; 194(6): 781 - 796. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. Ghiran, S. F. Barbashov, L. B. Klickstein, S. W. Tas, J. C. Jensenius, and A. Nicholson-Weller Complement Receptor 1/CD35 Is a Receptor for Mannan-binding Lectin J. Exp. Med., December 18, 2000; 192(12): 1797 - 1808. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Butko, A. Nicholson-Weller, and M. R. Wessels Role of Complement Component C1q in the IgG-Independent Opsonophagocytosis of Group B Streptococcus J. Immunol., September 1, 1999; 163(5): 2761 - 2768. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Borregaard and J. B. Cowland Granules of the Human Neutrophilic Polymorphonuclear Leukocyte Blood, May 15, 1997; 89(10): 3503 - 3521. [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |