The Journal of Immunology, Vol 134, Issue 3 1851-1858, Copyright © 1985 by American Association of Immunologists

ARTICLES

PMA induces the ligand-independent internalization of CR1 on human neutrophils

PS Changelian, RM Jack, LA Collins and DT Fearon

Phorbol myristate acetate (PMA) has been reported to confer on the C3b receptor (CR1) of neutrophils a capacity for phagocytosis of particles bearing C3b without the involvement of other membrane receptors. In the present study, we employed a monoclonal antibody, YZ-1, that is specific for CR1 to assess the effect of PMA on plasma membrane expression of CR1, total cellular CR1, and internalization of CR1 by neutrophils. PMA had a biphasic effect on the membrane expression of CR1 by purified neutrophils, with 4 ng/ml inducing a 60% increment in receptor expression, and higher concentrations causing up to a 70% decrement. PMA-dependent increases in CR1 expression were not accompanied by corresponding changes in total cellular CR1 and were preempted by treatment of cells with formyl-methionyl-leucyl- phenylalanine (FMLP). PMA-induced decreases in CR1 expression by neutrophils, as measured by binding of indirectly fluoresceinated or radiolabeled YZ-1, or of 125I-labeled dimeric C3b, were maximal with 20 to 30 ng/ml PMA, and occurred within 30 min of incubation at 37 degrees C. The PMA-dependent down-regulation of CR1 by neutrophils was not associated with a comparable decrease in total cellular CR1, and this response was observed to occur also with monocytes but not with peripheral blood lymphocytes. By tagging neutrophil CR1 with 125I-YZ-1 Fab and monitoring accessibility to Protease, intracellular CR1 (inaccessible) was discriminated from receptor on plasma membrane (accessible). Internalization of CR1 occurred within 5 min after addition of PMA to neutrophils, was dose dependent, and involved up to two-thirds of the tagged receptors. Therefore, PMA caused internalization of CR1 by neutrophils in the absence of ligand, indicating that this response was independent of a transmembrane signal generated by a C3b-CR1 interaction.

This article has been cited by other articles:

				I. Ghiran, A. M. Glodek, G. Weaver, L. B. Klickstein, and A. Nicholson-Weller Ligation of erythrocyte CR1 induces its clustering in complex with scaffolding protein FAP-1 Blood, October 15, 2008; 112(8): 3465 - 3473. [Abstract] [Full Text] [PDF]

				A. C. Jacobson and J. H. Weis Comparative Functional Evolution of Human and Mouse CR1 and CR2 J. Immunol., September 1, 2008; 181(5): 2953 - 2959. [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]

				L. Xiang, J. R. Rundles, D. R. Hamilton, and J. G. Wilson Quantitative Alleles of CR1: Coding Sequence Analysis and Comparison of Haplotypes in Two Ethnic Groups J. Immunol., November 1, 1999; 163(9): 4939 - 4945. [Abstract] [Full Text] [PDF]

				S. W. Tas, L. B. Klickstein, S. F. Barbashov, and A. Nicholson-Weller C1q and C4b Bind Simultaneously to CR1 and Additively Support Erythrocyte Adhesion J. Immunol., November 1, 1999; 163(9): 5056 - 5063. [Abstract] [Full Text] [PDF]

				C. Jost, L. Klickstein, E. Wetzler, A. Kumar, and M. Berger Intracellular Storage and Regulated Plasma Membrane Expression of Human Complement Receptor Type 1 in Rat Basophil Leukemia Cell Transfectants Blood, July 1, 1998; 92(1): 300 - 309. [Abstract] [Full Text] [PDF]

				R. Rogers, R. Jack, and S. Furlong Lipid and membrane protein transfer from human neutrophils to schistosomes is mediated by ligand binding J. Cell Sci., January 10, 1993; 106(2): 485 - 491. [Abstract] [PDF]

				R. Carter and D. Fearon CD19: lowering the threshold for antigen receptor stimulation of B lymphocytes Science, April 3, 1992; 256(5053): 105 - 107. [Abstract] [PDF]

				F. D. Moore Jr, S. H. Socher, and C. Davis Tumor Necrosis Factor and Endotoxin Can Cause Neutrophil Activation Through Separate Pathways Arch Surg, January 1, 1991; 126(1): 70 - 73. [Abstract] [PDF]

				D. Reed and F. D. Moore Jr Recombinant Human Tumor Necrosis Factor Increases Granulocyte Cell-Surface Complement Receptor Number Arch Surg, November 1, 1988; 123(11): 1333 - 1336. [Abstract] [PDF]