Generation of heterogeneous rabbit anti-DNP antibodies by gene conversion and hypermutation of rearranged VL and VH genes during clonal expansion of B cells in splenic germinal centers.
The mechanisms described here account for development of the heterogeneous high-affinity anti-DNP antibodies that rabbits can produce. Rearranged immunoglobulin light and heavy chain genes from single DNP-specific splenic germinal center B cells were amplified by PCR. We found that in clonal lineages, rearranged V[kappa] and V[H] are further diversified by gene conversion and somatic hypermutation. The positive and negative selection of amino acids in complementarity-determining regions observed allows emergence of a variety of different combining site structures. A by-product of the germinal center reaction may be cells with sequences altered by gene conversion that no longer react with the immunizing antigen but are a source of new repertoire. The splenic germinal center would thus play an additional role in adults similar to that of the appendix and other gut-associated lymphoid tissues of young rabbits.
Sehgal
D
D
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, 20892-1892, USA.
Schiaffella
E
E
Anderson
A O
AO
Mage
R G
RG
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D022801:Complementarity Determining Regions / Q000235:genetics; D004136:Dinitrobenzenes / Q000276:immunology*; D005785:Gene Conversion; D015321:Gene Rearrangement; D005803:Genes, Immunoglobulin; D018858:Germinal Center / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D011817:Rabbits; D013154:Spleen / Q000276:immunology*
D022801:Complementarity Determining Regions; D004136:Dinitrobenzenes; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region