These C4b knock-out mice exhibit an increased susceptibility to lethal infection by Group B streptococci.
Michael C. Carroll, The Center for Blood Research
Mice homozygous for the C4 (complement component C4) targeted mutation are viable and fertile. Homozygous mutants exhibit an increased susceptibility to lethal infection by Group B streptococci(GBS). C4 homozygous mutants show a similar susceptibility to GBS lethal infection as do C3 null mice, suggesting that the classical, and not alternative, pathway is primarily involved in antibody-independent humoral immunity to GBS. Homozygotes also demonstrate a profound defect in antibody response to T cell dependent antigens. They show a diminished level of peanut agglutin+ germinal centers and a failure in isotype switching despite normal B cell signalling in vitro.
The C4 locus was disrupted by the insertion of a PGK/Neo cassette. This resulted in the deletion of exons 23 to 29 (987 ntds). The targeting construct was transfected into J1 ES cells and successful transfectants were injected into 3.5 day old C57BL/6 blastocysts which were then implanted into the uterus of pseudopregnant females. Male chimeric mice were bred with C57BL/6 females. Mice were backcrossed to C57BL/6J until N5.
|Allele Name||targeted mutation 1, Michael C Carroll|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||C4b, complement component 4B (Chido blood group)|
|Strain of Origin||129S4/SvJae|
|Molecular Note||A genomic fragment corresponding to 987 nucleotides of coding sequence (exons 23-29) was replaced with a neomycin selection cassette. ELISA assays on serum derived from homozygous mice demonstrated that no detectable protein is produced from this allele.|
|Mutations Made By|| |
Michael Carroll, The Center for Blood Research
When maintaining a live colony, homozygous mice may be bred together.
When using the C4 KO mouse strain in a publication, please cite the originating article(s) and include JAX stock #003643 in your Materials and Methods section.