A team led by Professor Jim Riley of Perelman School of medicine of the University of Pennsylvania and Todd Allen of the Ragon Institute of Harvard University introduced a new bispecific car-t cell immunotherapy, which can help fight HIV infection. In recent years, car-t cells have provided a powerful tool for the treatment of cancer. The therapy uses the patient’s own immune T cells to express chimeric antigen receptor (car) so that T cells can recognize specific cells and clear them. < / P > < p > in addition to targeting cancer cells, different car designs can also allow T cells to recognize and eliminate other types of diseased cells. In this study, scientists designed a new car-t cell that can specifically target HIV infected cells. As the main target of HIV infection is T cells, so this car-t cells not only need to be able to survive and proliferate in vivo, but also need to be able to resist HIV infection. < / P > < p > to achieve this goal, researchers have developed a bispecific car-t cell with two cars on a single cell. Each car expresses the extracellular domain of CD4 protein, which enables it to target HIV infected cells; in addition, the two cars contain 4-1BB / CD3 – ζ and CD28 / CD3 – ζ domains respectively, the former can stimulate cell proliferation and persistence, and the latter is used to enhance the ability to kill infected cells. < / P > < p > at the same time, this car-t cells also added a membrane fusion inhibitor called c34-cxcr4, which is used to prevent HIV adhesion and protect car-t cells from HIV infection. As a result, car-t cells prepared by the researchers can recognize and kill HIV infected cells effectively, and have certain resistance to HIV infection. < / P > < p > in HIV infected mice, the researchers tested the effect of the new car-t cells. Compared with untreated controls, car-t cells made HIV replication slower and fewer cells were infected with the virus. The results of blood examination showed that after treatment, the viral burden of CD4 positive T cells was effectively reduced, which means that the main target of HIV infection has been effectively protected. In addition, this bispecific car-t cells, combined with existing antiretroviral (Art) drugs, can accelerate the inhibition of viral replication in HIV infected mice, twice as fast as art alone. This suggests that car-t cell therapy can reduce the viral repository that forms in animals during art, the researchers note. < / P > < p > mice receiving both car-t cells and art therapy achieved complete inhibition after 2 weeks of treatment, compared with 4 weeks in the control group only treated with art < / P > < p > these results “demonstrate that the new bispecific car-t cell product has stronger efficacy and potential for effective treatment of HIV infection”, the summary of the study paper concluded. < / P > < p > “this study uses relatively simple engineering methods to alter T cells, bringing about significant changes in efficacy and durability.” Professor Riley added, “this finding has important implications for using engineered T cells to fight HIV and cancer.” Global Tech