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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID 		Igltm2.1Bgmn
targeted mutation 2.1, Marianne Bruggemann
MGI:3701069
Summary 4 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
cx1
 		Ighmtm1Cgn/Ighmtm1Cgn
Igkctm1Bgmn/Igkctm1Bgmn
Igltm2.1Bgmn/Igltm2.1Bgmn 		involves: 129 MGI:3806699
cx2
 		Igkctm1Bgmn/Igkctm1Bgmn
Igltm2.1Bgmn/Igltm2.1Bgmn 		involves: 129P2/OlaHsd MGI:3806697
cx3
 		Ighmtm3Bgmn/Ighmtm3Bgmn
Igkctm1Bgmn/Igkctm1Bgmn
Igltm2.1Bgmn/Igltm2.1Bgmn 		involves: 129P2/OlaHsd * 129/Sv MGI:3806698
cx4
 		Igkctm1Bgmn/Igkctm1Bgmn
Igltm2.1Bgmn/Igltm2.1Bgmn 		involves: 129P2/OlaHsd * BALB/c * C57BL/6 * CBA MGI:3702904


Genotype
MGI:3806699
cx1
Allelic
Composition		 Ighmtm1Cgn/Ighmtm1Cgn
Igkctm1Bgmn/Igkctm1Bgmn
Igltm2.1Bgmn/Igltm2.1Bgmn
Genetic
Background		 involves: 129
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Ighmtm1Cgn mutation (18 available); any Ighm mutation (57 available)
Igkctm1Bgmn mutation (0 available); any Igkc mutation (9 available)
Igltm2.1Bgmn mutation (0 available); any Igl mutation (6 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
immune system
decreased IgG level ( J:130864 )
• IgG is not present in the sera
decreased IgM level ( J:130864 )
• IgM is not present in the sera

hematopoietic system
decreased IgG level ( J:130864 )
• IgG is not present in the sera
decreased IgM level ( J:130864 )
• IgM is not present in the sera




Genotype
MGI:3806697
cx2
Allelic
Composition		 Igkctm1Bgmn/Igkctm1Bgmn
Igltm2.1Bgmn/Igltm2.1Bgmn
Genetic
Background		 involves: 129P2/OlaHsd
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Igkctm1Bgmn mutation (0 available); any Igkc mutation (9 available)
Igltm2.1Bgmn mutation (0 available); any Igl mutation (6 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
immune system
abnormal B cell differentiation ( J:130864 )
• B cell development is partially blocked at the small pre-B cell stage
• cells are released from the bone marrow as B220+CD21/CD35+ B cells
• there is also a small population (0.8%) of B cells expressing Igbeta
abnormal immunoglobulin heavy chain V(D)J recombination ( J:130864 )
• many heavy chain antibodies produced by B cells in these mice lack the Ch1 exon
abnormal plasma cell morphology ( J:130864 )
• plasma cells secrete heavy-chain only IgG
decreased IgG level ( J:130864 )
• reduced but detectable amounts of IgG antibody are found in the sera
• antibodies consist of heavy chain only homodimers
• antigen-specific IgG can be generated by several immunizations of OVA peptide
• these immunizations also result in increases to total IgG levels
decreased IgM level ( J:130864 )
• IgM is not present in the sera

hematopoietic system
abnormal B cell differentiation ( J:130864 )
• B cell development is partially blocked at the small pre-B cell stage
• cells are released from the bone marrow as B220+CD21/CD35+ B cells
• there is also a small population (0.8%) of B cells expressing Igbeta
abnormal immunoglobulin heavy chain V(D)J recombination ( J:130864 )
• many heavy chain antibodies produced by B cells in these mice lack the Ch1 exon
abnormal plasma cell morphology ( J:130864 )
• plasma cells secrete heavy-chain only IgG
decreased IgG level ( J:130864 )
• reduced but detectable amounts of IgG antibody are found in the sera
• antibodies consist of heavy chain only homodimers
• antigen-specific IgG can be generated by several immunizations of OVA peptide
• these immunizations also result in increases to total IgG levels
decreased IgM level ( J:130864 )
• IgM is not present in the sera




Genotype
MGI:3806698
cx3
Allelic
Composition		 Ighmtm3Bgmn/Ighmtm3Bgmn
Igkctm1Bgmn/Igkctm1Bgmn
Igltm2.1Bgmn/Igltm2.1Bgmn
Genetic
Background		 involves: 129P2/OlaHsd * 129/Sv
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Ighmtm3Bgmn mutation (0 available); any Ighm mutation (57 available)
Igkctm1Bgmn mutation (0 available); any Igkc mutation (9 available)
Igltm2.1Bgmn mutation (0 available); any Igl mutation (6 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
hematopoietic system
abnormal B cell differentiation ( J:130864 )
• B cell development is partially blocked at the small pre-B cell stage but the expression of a heavy chain-only BCR overcomes this block
• there is a B cell population that makes up 8.4% of splenocytes that express Igbeta
decreased IgG level ( J:130864 )
• reduced but detectable amounts of IgG antibody are found in the sera
• antibodies consist of heavy chain only covalently linked homodimers
decreased IgM level ( J:130864 )
• IgM is present at reduced amounts in the sera
• IgM consist only of heavy chains that are non-covalently linked

immune system
abnormal B cell differentiation ( J:130864 )
• B cell development is partially blocked at the small pre-B cell stage but the expression of a heavy chain-only BCR overcomes this block
• there is a B cell population that makes up 8.4% of splenocytes that express Igbeta
decreased IgG level ( J:130864 )
• reduced but detectable amounts of IgG antibody are found in the sera
• antibodies consist of heavy chain only covalently linked homodimers
decreased IgM level ( J:130864 )
• IgM is present at reduced amounts in the sera
• IgM consist only of heavy chains that are non-covalently linked




Genotype
MGI:3702904
cx4
Allelic
Composition		 Igkctm1Bgmn/Igkctm1Bgmn
Igltm2.1Bgmn/Igltm2.1Bgmn
Genetic
Background		 involves: 129P2/OlaHsd * BALB/c * C57BL/6 * CBA
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Igkctm1Bgmn mutation (0 available); any Igkc mutation (9 available)
Igltm2.1Bgmn mutation (0 available); any Igl mutation (6 available)
♀ phenotype observed in females
♂ phenotype observed in males
N normal phenotype
hematopoietic system
arrested B cell differentiation ( J:118712 )
• development is blocked at pre-B-II to immature B cell transition stage
absent B cells ( J:118712 )
• IgM+ B cells are undetectable in spleens of mutants

immune system
arrested B cell differentiation ( J:118712 )
• development is blocked at pre-B-II to immature B cell transition stage
absent B cells ( J:118712 )
• IgM+ B cells are undetectable in spleens of mutants




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Send questions and comments to User Support. 		last database update
09/30/2025
MGI 6.24 		The Jackson Laboratory