CTLA4 Ig-24 Cells

CTLA4 Ig-24 cells, derived from an adult female Chinese hamster (Cricetulus griseus), are a spontaneously immortalized cell line which have been genetically modified by introducing the human CTLA-4 gene, resulting in the expression of a fusion protein. The fusion protein possesses a dominant attribute of CTLA4Ig, making CTLA4 Ig-24 cells a unique and essential tool in immunology research. CTLA-4, a member of the immunoglobulin superfamily, is primarily expressed in activated T cells and acts as an inhibitory signal transmitter to regulate T cell function. It shares homology with CD28, a T-cell co-stimulatory protein, and both molecules bind to CD80 (B7-1) and CD86 (B7-2) proteins on antigen-presenting cells. CTLA-4 demonstrates a greater affinity and avidity for CD80 and CD86 than CD28, allowing it to outcompete CD28 for binding to these ligands. By doing so, CTLA-4 transmits an inhibitory signal to T cells, while CD28 transmits a stimulatory signal. This intricate regulatory mechanism is pivotal in maintaining immune balance and preventing excessive immune responses. Interestingly, CTLA-4 is also found in regulatory T cells (Tregs) and contributes to their inhibitory function. When T cells are activated through the T cell receptor (TCR) and CD28, the expression of CTLA-4 increases. Furthermore, CTLA-4 may influence cell motility and signal signalling through the PI3 kinase pathway.