Defining the structural correlates responsible for loss of arsonate affinity in an IDCR antibody isolated from an autoimmune mouse.
Immunization of the autoimmune mouse strain (M x A) Id/lpr with Ars-KLH, has been shown to elicit a prolonged anti-Ars IdCR response similar to that found in A/J mice. Cell fusion of splenocytes from a diseased mouse previously immunized with Ars-KLH resulted in a monoclonal antibody, 1-52.30, that was found to express the strain A major cross-reactive idiotype, but failed to bind Ars. Nucleotide sequence analysis demonstrated that 1-52.30: (a) used the "canonical" combination of gene segments associated with this idiotype, and (b) exhibited a pattern of somatic mutation consistent with selection for high affinity Ars binding. Two amino acids, VL 91 and 93, were mutated in 36-65, the germline equivalent of the IdCR antibodies, to 1-52.30-like residues (91G-->D, 93T-->M). The results of the mutagenesis showed that changing a single light chain residue, VL 91, from glycine to aspartic acid, resulted in a dramatic loss of Ars binding activity.
Panka
D J
DJ
Department of Microbiology, Boston University Medical School, MA 02118.
Very
D L
DL
Jacobson
B A
BA
Kussie
P H
PH
Parhami-Seren
B
B
Margolies
M N
MN
Marshak-Rothstein
A
A
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001151:Arsenic / Q000276:immunology*; D001152:Arsenicals; D001327:Autoimmune Diseases / Q000276:immunology*; D001483:Base Sequence; D001666:Binding Sites, Antibody; D007130:Immunoglobulin Idiotypes / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D016296:Mutagenesis; D013329:Structure-Activity Relationship
D000911:Antibodies, Monoclonal; D001152:Arsenicals; D007130:Immunoglobulin Idiotypes; C054806:arsonic acid; D001151:Arsenic