The targeted Il21 gene encodes an immunoregulatory cytokine important in innate and adaptive immune responses. Mutations in this gene have been associated with common variable immunodeficiency-11. These IL21-VFP mice express VFP, vivid Verde fluorescent protein, from the endogenous Il21 locus. Green fluorescence is detected by flow cytometry in a large number of CD44+ICOS+CD4+ T cells and approximately 40% of PD1+ cells in immunologically challenged IL21-VFP mice. When crossed to an autoimmune disease model strain, immunohistochemical analysis of spleen from the double mutant mice shows that the VFP fluorescence co-localizes with IL21 expressing cells. Heterozygotes and homozygotes exhibit similar percentages of VFP positive cells. Homozygotes are viable and fertile. Expression of the endogenous Il21 gene is not altered. Green-emitting VFP was isolated from the tropical scleractinian coral Cyphastrea microphthalma, rapidly matures at 37&deg;C and exhibits a maximum excitation peak at 491nm and a maximum emission peak at 503 nm, with brighter fluorescence than EGFP. In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. This is the case for the strain above. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available. &nbsp;

This IL21-VFP knock-in strain expresses VFP (vivid Verde fluorescent protein) from the endogenous Il21 locus and is useful as a reporter for IL21-expressing CD4 T follicular helper (TFH) cells, which are the precursors of mature TFH cells.

Typically mice are recovered in 12-16 weeks. Contact Customer Service to place an order or for more information.

<a target="_blank" href="https://www.jax.org/jax-mice-and-services/customer-support" rel="noreferrer">Contact Customer Service</a> for more information.