Protection of Mucosal Epithelia by IgA: Intracellular Neutralization and Excretion of Antigens
Mucosal immunoglobulin A (IgA) antibodies are synthesized by local plasma cells in the lamina propria and are largely destined for export through the lining epithelium into the luminal secretions. Here, IgA antibodies can bind antigens and exclude them from the body, as has long been appreciated. It is becoming increasingly apparent, though, that passage through mucosal epithelium creates additional opportunities for IgA antibodies to function in host defense. For example, IgA antibodies against viruses can directly counter infections within mucosal epithelium, and immune complexes formed in the lamina propria containing locally produced IgA antibodies can pass through the epithelium via the same route and mechanism as free IgA. Thus, IgA antibodies might first encounter antigens in three anatomic compartments in relation to mucosal epithelium: in the lumen, in the epithelium itself, or in the lamina propria (Lamm, 1997). The nonclassical defense functions of IgA, in which IgA antibodies initially bind antigens in the lamina propria or inside the lining epithelial cells, are the focus of this chapter.
KeywordsLamina Propria Mucosal Epithelium Secretory Component Mucosal Lamina Propria Human Intestinal Epithelial Cell Line
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- Bruno, M. E. C., and Kaetzel, C.S. (2005). Long-term exposure of the HT-29 human intestinal epithelial cell line to TNF causes sustained up-regulation of the polymeric Ig receptor and proinflammatory genes through transcriptional and posttranscriptional mechanisms. J. Immunol. 174:7278–7284.PubMedGoogle Scholar
- Corthésy, B., Benureau, Y., Perrier, C., Fourgeux, C., Parez, N., Greenberg, H., and Schwartz-Cornil, I. (2006). Rotavirus anti-VP6 secretory immunoglobulin A contributes to protection via intracellular neutralization but not via immune exclusion. J Virol. 80:10692–10699.CrossRefPubMedGoogle Scholar
- Emancipator, S. N., Mestecky, J., and Lamm, M. E. (2005). IgA nephropathy and related diseases. In: Mestecky J., Bienenstock, J., Lamm, M. E., Mayer, L., McGhee, J. R., and Strober, W. (eds.), Mucosal Immunology, 3rd ed. Elsevier, San Diego, pp. 1580–1600.Google Scholar
- Fujioka, H. S., Emancipator, S. N., Aikawa, M., Huang, D. S., Blatnik, F., Karban, T., DeFife, K., and Mazanec, M. B. (1998). Immunocytochemical colocalization of specific immunoglobulin A with sendai virus protein in infected polarized epithelium. J. Exp. Med. 188:1223–1229.CrossRefPubMedGoogle Scholar
- Kaetzel, C. S., Robinson, J. K., Chintalacharuvu, K. R., Vaerman, J.-P., and Lamm, M. E. (1991). The polymeric immunoglobulin receptor (secretory component) mediates transport of immune complexes across epithelial cells: A local defense function for IgA. Proc. Natl. Acad. Sci. USA 88:8796–8800.CrossRefPubMedGoogle Scholar
- Obara, W., Iida, A., Suzuki, Y., Tanaka, T., Akiyama, F., Maeda, S., Ohnishi, Y., Yamada, R., Tsunoda, T., Takei, T., Ito, K., Honda, K., Uchida, K., Tsuchiya, K., Yumura, W., Ujiie, T., Nagane, Y., Nitta, K., Miyano, S., Narita, I., Gejyo, F., Nihei, H., Fujioka, T., and Nakamura, Y. (2003). Association of single-nucleotide polymorphisms in the polymeric immunoglobulin receptor gene with immunoglobulin A nephropathy (IgAN) in Japanese patients. J. Hum. Genet. 48:293–299.PubMedGoogle Scholar