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Restricted immunoglobulin variable region (Ig V) gene expression accompanies secondary rearrangements of light chain Ig V genes in mouse plasmacytomas.

Diaw L, Siwarski D, Coleman A, Kim J, Jones GM, Dighiero G, Huppi K - J. Exp. Med. (1999)

Bottom Line: The many binding studies of monoclonal immunoglobulin (Ig) produced by plasmacytomas have found no universally common binding properties, but instead, groups of plasmacytomas with specific antigen-binding activities to haptens such as phosphorylcholine, dextrans, fructofuranans, or dinitrophenyl.Subsequently, it was found that plasmacytomas with similar binding chain specificities not only expressed the same idiotype, but rearranged the same light (V(L)) and heavy (V(H)) variable region genes to express a characteristic monoclonal antibody.These results suggest that plasmacytomas use a restricted population of B cells that may still be undergoing rearrangement, thereby bypassing the allelic exclusion normally associated with expression of antibody genes.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.

ABSTRACT
The many binding studies of monoclonal immunoglobulin (Ig) produced by plasmacytomas have found no universally common binding properties, but instead, groups of plasmacytomas with specific antigen-binding activities to haptens such as phosphorylcholine, dextrans, fructofuranans, or dinitrophenyl. Subsequently, it was found that plasmacytomas with similar binding chain specificities not only expressed the same idiotype, but rearranged the same light (V(L)) and heavy (V(H)) variable region genes to express a characteristic monoclonal antibody. In this study, we have examined by enzyme-linked immunosorbent assay five antibodies secreted by silicone-induced mouse plasmacytomas using a broader panel of antigens including actin, myosin, tubulin, single-stranded DNA, and double-stranded DNA. We have determined the Ig heavy and light chain V gene usage in these same plasmacytomas at the DNA and RNA level. Our studies reveal: (a) antibodies secreted by plasmacytomas bind to different antigens in a manner similar to that observed for natural autoantibodies; (b) the expressed Ig heavy genes are restricted in V gene usage to the V(H)-J558 family; and (c) secondary rearrangements occur at the light chain level with at least three plasmacytomas expressing both kappa and lambda light chain genes. These results suggest that plasmacytomas use a restricted population of B cells that may still be undergoing rearrangement, thereby bypassing the allelic exclusion normally associated with expression of antibody genes.

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Southern hybridization assay for c-Myc and Pvt 1 rearrangements in SIPC tumors. Shown top (c-Myc, EcoR1) and bottom (Pvt 1, BamH1) are the following tumors: lane 1, SIPC3385; lane 2, SIPC3308; lane 3, SIPC3301; lane 4, SIPC3336; lane 5, SIPC3282; and lane 6, BALB/c. Arrows depict the germline (nonrearranged fragments). Two samples (SIPC3385 and SIPC3301) contain rearranged bands with c-Myc, whereas no rearrangements are found with Pvt 1.
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Figure 2: Southern hybridization assay for c-Myc and Pvt 1 rearrangements in SIPC tumors. Shown top (c-Myc, EcoR1) and bottom (Pvt 1, BamH1) are the following tumors: lane 1, SIPC3385; lane 2, SIPC3308; lane 3, SIPC3301; lane 4, SIPC3336; lane 5, SIPC3282; and lane 6, BALB/c. Arrows depict the germline (nonrearranged fragments). Two samples (SIPC3385 and SIPC3301) contain rearranged bands with c-Myc, whereas no rearrangements are found with Pvt 1.

Mentions: Cytogenetic studies have revealed that a majority of PCs contain reciprocal T(12;15) translocations 1. Alternatively, several SIPC tumors exhibit a reciprocal T(6;15) translocation (considered to be the variant translocation), as demonstrated by the SKY™ analysis performed on two representative SIPC tumors (Fig. 1). While SKY™ cytogenetics is a good indicator of T(12;15) or T(6;15) translocations, it is not entirely certain whether c-Myc or Pvt 1 is targeted by these translocations, as we have only found two SIPC tumors with c-Myc rearrangements (SIPC3385, SIPC3301) and no tumors with Pvt 1 rearrangements at the Southern hybridization level (Table , and Fig. 2). The assay for molecular rearrangement is based on utilization of a series of hybridization probes surrounding the major breakpoints of Pvt 1 or c-Myc, and by incorporating large restriction fragments into the analyses 11. The absence of detectable rearrangements with Pvt 1 or c-Myc in such a large number of SIPC tumors (Table , and data not shown) suggests that, in general, SIPC-associated translocations could reside outside the usual or more common breakpoint locations, and may not be detectable with the probes used in this study.


Restricted immunoglobulin variable region (Ig V) gene expression accompanies secondary rearrangements of light chain Ig V genes in mouse plasmacytomas.

Diaw L, Siwarski D, Coleman A, Kim J, Jones GM, Dighiero G, Huppi K - J. Exp. Med. (1999)

Southern hybridization assay for c-Myc and Pvt 1 rearrangements in SIPC tumors. Shown top (c-Myc, EcoR1) and bottom (Pvt 1, BamH1) are the following tumors: lane 1, SIPC3385; lane 2, SIPC3308; lane 3, SIPC3301; lane 4, SIPC3336; lane 5, SIPC3282; and lane 6, BALB/c. Arrows depict the germline (nonrearranged fragments). Two samples (SIPC3385 and SIPC3301) contain rearranged bands with c-Myc, whereas no rearrangements are found with Pvt 1.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2195694&req=5

Figure 2: Southern hybridization assay for c-Myc and Pvt 1 rearrangements in SIPC tumors. Shown top (c-Myc, EcoR1) and bottom (Pvt 1, BamH1) are the following tumors: lane 1, SIPC3385; lane 2, SIPC3308; lane 3, SIPC3301; lane 4, SIPC3336; lane 5, SIPC3282; and lane 6, BALB/c. Arrows depict the germline (nonrearranged fragments). Two samples (SIPC3385 and SIPC3301) contain rearranged bands with c-Myc, whereas no rearrangements are found with Pvt 1.
Mentions: Cytogenetic studies have revealed that a majority of PCs contain reciprocal T(12;15) translocations 1. Alternatively, several SIPC tumors exhibit a reciprocal T(6;15) translocation (considered to be the variant translocation), as demonstrated by the SKY™ analysis performed on two representative SIPC tumors (Fig. 1). While SKY™ cytogenetics is a good indicator of T(12;15) or T(6;15) translocations, it is not entirely certain whether c-Myc or Pvt 1 is targeted by these translocations, as we have only found two SIPC tumors with c-Myc rearrangements (SIPC3385, SIPC3301) and no tumors with Pvt 1 rearrangements at the Southern hybridization level (Table , and Fig. 2). The assay for molecular rearrangement is based on utilization of a series of hybridization probes surrounding the major breakpoints of Pvt 1 or c-Myc, and by incorporating large restriction fragments into the analyses 11. The absence of detectable rearrangements with Pvt 1 or c-Myc in such a large number of SIPC tumors (Table , and data not shown) suggests that, in general, SIPC-associated translocations could reside outside the usual or more common breakpoint locations, and may not be detectable with the probes used in this study.

Bottom Line: The many binding studies of monoclonal immunoglobulin (Ig) produced by plasmacytomas have found no universally common binding properties, but instead, groups of plasmacytomas with specific antigen-binding activities to haptens such as phosphorylcholine, dextrans, fructofuranans, or dinitrophenyl.Subsequently, it was found that plasmacytomas with similar binding chain specificities not only expressed the same idiotype, but rearranged the same light (V(L)) and heavy (V(H)) variable region genes to express a characteristic monoclonal antibody.These results suggest that plasmacytomas use a restricted population of B cells that may still be undergoing rearrangement, thereby bypassing the allelic exclusion normally associated with expression of antibody genes.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Genetics, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.

ABSTRACT
The many binding studies of monoclonal immunoglobulin (Ig) produced by plasmacytomas have found no universally common binding properties, but instead, groups of plasmacytomas with specific antigen-binding activities to haptens such as phosphorylcholine, dextrans, fructofuranans, or dinitrophenyl. Subsequently, it was found that plasmacytomas with similar binding chain specificities not only expressed the same idiotype, but rearranged the same light (V(L)) and heavy (V(H)) variable region genes to express a characteristic monoclonal antibody. In this study, we have examined by enzyme-linked immunosorbent assay five antibodies secreted by silicone-induced mouse plasmacytomas using a broader panel of antigens including actin, myosin, tubulin, single-stranded DNA, and double-stranded DNA. We have determined the Ig heavy and light chain V gene usage in these same plasmacytomas at the DNA and RNA level. Our studies reveal: (a) antibodies secreted by plasmacytomas bind to different antigens in a manner similar to that observed for natural autoantibodies; (b) the expressed Ig heavy genes are restricted in V gene usage to the V(H)-J558 family; and (c) secondary rearrangements occur at the light chain level with at least three plasmacytomas expressing both kappa and lambda light chain genes. These results suggest that plasmacytomas use a restricted population of B cells that may still be undergoing rearrangement, thereby bypassing the allelic exclusion normally associated with expression of antibody genes.

Show MeSH
Related in: MedlinePlus