HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Martin, T. M. Articles by Rittenberg, M. B. Search for Related Content PubMed PubMed Citation Articles by Martin, T. M. Articles by Rittenberg, M. B.

Inefficient Assembly and Intracellular Accumulation of Antibodies with Mutations in V_H CDR2¹

Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, OR 97201

We previously described secretion defects in four mutants of the murine anti-phosphocholine Ab, T15. The mutant heavy (H) chains had amino acid replacements in the V_H complementarity-determining region 2 (HCDR2) and were expressed at normal intracellular levels. Here, the intracellular fate of the secretion-defective mutant heavy chains was investigated. Metabolic labeling demonstrated that the T15 wild-type Ab was secreted within a 4-h chase. In contrast, the mutant H chains accumulated with intracellular t_1/2 values ranging from 10 to 24 h. The mutant H chains were associated with increased levels of the molecular chaperones BiP and GRP94, and remained endoglycosidase H sensitive, suggesting retention in the endoplasmic reticulum. Assembly of the mutant H chains with T15 light (L) chain was arrested at the H₂ and H₂L intermediate stages of the T15 wild-type pathway (H₂ H₂L H₂L₂). Even though some assembly with L chain occurred, it was not as a secretion-competent H₂L₂ Ig moiety. The T15 L chains coexpressed with mutant H chains were degraded efficiently except for a minor L chain population with a long t_1/2 that was apparently protected at the H₂L stage. To our knowledge, this is the first study demonstrating that intracellular half-lives of Ig H and L chains can be influenced by somatic mutations in HCDR2.

This article has been cited by other articles:

				G. D. Wiens, M. Brown, and M. B. Rittenberg Repertoire Shift in the Humoral Response to Phosphocholine-Keyhole Limpet Hemocyanin: VH Somatic Mutation in Germinal Center B Cells Impairs T15 Ig Function J. Immunol., May 15, 2003; 170(10): 5095 - 5102. [Abstract] [Full Text] [PDF]

				E. A. Whitcomb, T. M. Martin, and M. B. Rittenberg Restoration of Ig Secretion: Mutation of Germline-Encoded Residues in T15L Chains Leads to Secretion of Free Light Chains and Assembled Antibody Complexes Bearing Secretion-Impaired Heavy Chains J. Immunol., February 15, 2003; 170(4): 1903 - 1909. [Abstract] [Full Text] [PDF]

				G. D. Wiens, A. Lekkerkerker, I. Veltman, and M. B. Rittenberg Mutation of a Single Conserved Residue in VH Complementarity-Determining Region 2 Results in a Severe Ig Secretion Defect J. Immunol., August 15, 2001; 167(4): 2179 - 2186. [Abstract] [Full Text] [PDF]

				T. O'Hare, G. D. Wiens, E. A. Whitcomb, C. A. Enns, and M. B. Rittenberg Cutting Edge: Proteasome Involvement in the Degradation of Unassembled Ig Light Chains J. Immunol., July 1, 1999; 163(1): 11 - 14. [Abstract] [Full Text] [PDF]

				G. D. Wiens, T. O'Hare, and M. B. Rittenberg Recovering Antibody Secretion Using a Hapten Ligand as a Chemical Chaperone J. Biol. Chem., October 26, 2001; 276(44): 40933 - 40939. [Abstract] [Full Text] [PDF]