The Journal of Immunology, Vol 155, Issue 2 715-721, Copyright © 1995 by American Association of Immunologists

ARTICLES

Dimeric and tetrameric IgA are transcytosed equally by the polymeric Ig receptor

W Song, JP Vaerman and KE Mostov
Department of Anatomy, University of California, San Francisco 94143, USA.

Polymeric IgA (pIgA) is transcytosed across epithelial cells and into external secretions by the polymeric Ig receptor (pIgR). Binding of dimeric IgA (dIgA) to the pIgR stimulates transcytosis of the pIgR. The pIgA in secretions is found as dimers (dIgA) and higher polymers, such as tetramers (tIgA), but little is known of the functional significance of the different sizes. Here we compared the ability of dIgA and tIgA to perform three functions that are essential to their transport into mucosal secretions. 1) Equilibrium binding studies showed that there were twice as many binding sites for tIgA as dIgA at the basolateral cell surface, but that the affinity of these sites for tIgA was one- half of that for dIgA. 2) Both dIgA and tIgA were rapidly transcytosed by the pIgR, although transcytosis of tIgA was slower. 3) Both dIgA and tIgA could stimulate transcytosis of the pIgR, although tIgA was less effective. The possible implications of these findings for the relative biologic roles of dIgA and tIgA are discussed.

This article has been cited by other articles:

				M. J. Lewis, R. J. Pleass, M. R. Batten, J. D. Atkin, and J. M. Woof Structural Requirements for the Interaction of Human IgA with the Human Polymeric Ig Receptor J. Immunol., November 15, 2005; 175(10): 6694 - 6701. [Abstract] [Full Text] [PDF]

				K. Pal, C. S. Kaetzel, K. Brundage, C. A. Cunningham, and C. F. Cuff Regulation of polymeric immunoglobulin receptor expression by reovirus J. Gen. Virol., August 1, 2005; 86(8): 2347 - 2357. [Abstract] [Full Text] [PDF]

				S. C. Brock, P. A. McGraw, P. F. Wright, and J. E. Crowe Jr. The Human Polymeric Immunoglobulin Receptor Facilitates Invasion of Epithelial Cells by Streptococcus pneumoniae in a Strain-Specific and Cell Type-Specific Manner Infect. Immun., September 1, 2002; 70(9): 5091 - 5095. [Abstract] [Full Text] [PDF]

				P. Crottet, M. C. Peitsch, C. Servis, and B. Corthesy Covalent Homodimers of Murine Secretory Component Induced by Epitope Substitution Unravel the Capacity of the Polymeric Ig Receptor to Dimerize Noncovalently in the Absence of IgA Ligand J. Biol. Chem., October 29, 1999; 274(44): 31445 - 31455. [Abstract] [Full Text] [PDF]

				P. Crottet and B. Corthesy Mapping the Interaction Between Murine IgA and Murine Secretory Component Carrying Epitope Substitutions Reveals a Role of Domains II and III in Covalent Binding to IgA J. Biol. Chem., October 29, 1999; 274(44): 31456 - 31462. [Abstract] [Full Text] [PDF]

				K. L. Singer and K. E. Mostov Dimerization of the Polymeric Immunoglobulin Receptor Controls Its Transcytotic Trafficking Mol. Biol. Cell, April 1, 1998; 9(4): 901 - 915. [Abstract] [Full Text]

				C.-L. Ha and B. Woodward Reduction in the Quantity of the Polymeric Immunoglobulin Receptor Is Sufficient to Account for the Low Concentration of Intestinal Secretory Immunoglobulin A in a Weanling Mouse Model of Wasting Protein-Energy Malnutrition J. Nutr., March 1, 1997; 127(3): 427 - 435. [Abstract] [Full Text]