What are the applications of CD4?

CD4 cells, also known as CD4+ T cells or T-helper cells, are a crucial component of the immune system. These cells have significant applications in biomedical and molecular biology research, particularly with regard to their role in diagnosing and treating human immunodeficiency virus (HIV). 

CD4 acts as a high affinity receptor for human immunodeficiency virus, allowing the virus to enter host T cells. As the infection progresses, HIV attacks and destroys CD4 cells while also hampering the production of new CD4 cells. This drastically reduces their numbers and leaves the host susceptible to various infections. 

In HIV treatment, monitoring CD4 counts is a common method used to evaluate the health of the immune system in HIV-infected patients. Low CD4 counts indicate the progression of HIV infection and an increased risk of opportunistic infections and other complications. HIV treatment aims to suppress the virus and maintain or restore CD4 counts, which helps in managing the infection and preventing AIDS-related illnesses.