The mouse antibody response to infection with Cryptococcus neoformans: VH and VL usage in polysaccharide binding antibodies.
Cryptococcus neoformans is a ubiquitous fungus that can cause serious infections in humans. The fungus has a polysaccharide (C. neoformans capsular polysaccharide; CNPS) capsule that contributes to its pathogenicity and can elicit an antibody response. Nevertheless, only 4 of 60 BALB/c mice chronically infected with C. neoformans had a detectable increase in serum anti-CNPS. The sera of three responder mice contained both IgM and IgG anti-CNPS antibody, and the titers of lambda and kappa anti-CNPS antibody were approximately equal. Eight IgM and one IgG3 monoclonal antibodies (mAbs) were generated from the spleen of one responder mouse, and one IgA was generated from the spleen of another mouse. Seven of the IgMs, the IgG3, and the IgA mAb had lambda light chains and were specific for serotype D CNPS. Molecular analysis confirmed that this was a highly restricted antibody response. All of the D-specific antibodies used VH441, JH3, and either V lambda 2/J lambda 2 or V lambda 1/J lambda 1, and all had the same heavy chain CDR3 amino acid sequence, even though there were differences in the nucleotide sequence of the N/D segment. One IgM mAb reacted with both serotype A and D CNPS, and this mAb used different VH and JH genetic elements and had kappa light chains. All the anti-CNPS mAbs used J proximal VH gene elements that have previously been shown to bind dextran and other polysaccharides. Sequence and Southern blot analysis indicate that the serotype-D CNPS-specific mAbs arose from only a few precursor B cells.
Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York 10461.
A
A
Casadevall
M D
MD
Scharff
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D000917:Antibody Formation; D000936:Antigen-Antibody Complex; D001483:Base Sequence; D015139:Blotting, Southern; D003453:Cryptococcosis / Q000276:immunology*; D003455:Cryptococcus neoformans / Q000276:immunology; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005455:Fluorescent Antibody Technique; D007074:Immunoglobulin G / Q000032:analysis / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000032:analysis / Q000235:genetics*; D007133:Immunoglobulin Joining Region / Q000235:genetics; D007147:Immunoglobulin Light Chains / Q000032:analysis / Q000235:genetics*; D007075:Immunoglobulin M / Q000032:analysis / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000032:analysis / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D011134:Polysaccharides / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics* / Q000302:isolation & purification; D015183:Restriction Mapping
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D007133:Immunoglobulin Joining Region; D007147:Immunoglobulin Light Chains; D007075:Immunoglobulin M; D007135:Immunoglobulin Variable Region; D015345:Oligonucleotide Probes; D011134:Polysaccharides; D012333:RNA, Messenger; D011061:Poly A; D004247:DNA