Summary
A bioRxiv preprint reports that CD19-targeted engineered regulatory T cells persisted for more than four months and reduced several measures of lupus in two mouse models. The findings are preclinical, not results from patients.
A bioRxiv preprint reports that regulatory T cells engineered to target CD19 reduced autoimmune activity and improved kidney measures in two mouse models of systemic lupus erythematosus (SLE). The engineered cells persisted for more than four months in the animals. The work is preclinical: it includes cell experiments and mouse studies, not treatment of people with lupus.
Engineering a targeted regulatory cell
In SLE, immune responses against the body's own tissues can involve self-reactive B and T cells. B cells can produce autoantibodies, while regulatory T cells, or Tregs, help restrain immune activity. The researchers aimed to combine that suppressive role with targeted recognition of B cells.
They added a chimeric antigen receptor (CAR) that recognises CD19, a marker on B cells, and used homology-directed repair at the FOXP3 gene locus to drive stable FOXP3 expression in CD4 T cells. FOXP3 is central to the regulatory T-cell programme. The resulting cells, called CAR19 EngTreg, expressed standard Treg markers and produced little inflammatory cytokine, according to the preprint.
In laboratory experiments, the engineered cells blocked human B cells from differentiating into antibody-secreting plasma cells. In humanized mouse models, they reduced B-cell numbers and tissue inflammation, with lower inflammatory cytokine production than conventional CD19 CAR effector T cells. In a separate, short-term mouse model of imiquimod-induced inflammation, the cells reduced skin pathology, spleen size and inflammatory cytokines.
Lupus-model results and their significance
The central findings came from two distinct mouse models of lupus. The researchers report that CAR19 EngTreg cells persisted for more than four months and were associated with fewer autoimmune B- and T-cell populations, sustained reductions in multiple autoantibodies, and improved kidney function and tissue histopathology.
The approach is designed to do more than deplete B cells: it pairs B-cell targeting with regulatory activity that may also suppress other autoimmune effector cells. That combination could be relevant to efforts to establish longer-lasting immune control, rather than relying only on removing B cells. The mouse results make that a research direction, not a demonstrated treatment benefit in people.
The paper is a bioRxiv preprint. Its disclosures list GentiBio as a funder and identify several authors as current or former company employees; the authors also report related patent interests.