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Presentation of igg2a antigens to class ii‐restricted t cells by stably transfected b lymphoma cells
Author(s) -
Bikoff Elizabeth K.,
Eckhardt Laurel A.
Publication year - 1989
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.1830191022
Subject(s) - biology , microbiology and biotechnology , antigen , transfection , antibody , allotype , immunoglobulin light chain , immunoglobulin heavy chain , b cell , cell culture , immunology , genetics
Abstract Here we describe a panel of BALB/c T cells specific for IgG2a of the b allotype in association with I‐A d . We used DNA‐mediated gene transfer techniques to localize antigenic determinants recognized by responding T cells. Initially a truncated IgG2a a gene comprising a variable domain and the C H 3 domain (not including the membrane exons) from the BALB/c IgG2a a heavy chain was introduced into myeloma cells. The V‐C H 3 protein was expressed at high levels under control of the Ig heavy chain enhancer. Secretion of the V‐C H 3 protein did not require assembly of H‐H dimers or an association with light chains. To generate stably transfected B cell lines that would stimulate our class II‐restricted T cells, we replaced most of the BALB/c IgG2a a C H 3 exon with C H 3 coding sequences from a C57BL/6 IgG2a b cDNA clone and introduced these constructs into Ia + B lymphoma cells. The IgG2a b C H 3‐transfected B cells were recognized by BALB/c Igh‐1b‐specific T cell hybrids in the absence of exogenous antigen. Experiments using glutaraldehyde‐fixed cells as stimulators indicate that presentation of the secreted form of V‐IgG2a b C H 3 requires processing. We found that a significant fraction of the endogenously synthesized V‐IgG2a b C H 3 protein was, however, present as already processed antigen.