The correct answer is option A – CD4 self-reactive T cells. Regulatory T cells also called Tregs are types of T cells that have a role in suppressing cells of the immune system. They help to control the response of the immune system to self and foreign antigen. Regulatory T cells help the body to be able to tell the self and non-self apart.
They also play an important role in preventing autoimmune diseases. In the case where there is a problem with the regulatory cells, autoimmune diseases may occur. Regulatory CD4 T cells ensure that CD 4 self-reactive T cells are suppressed. They produce substances such as Interleukin 10, adenosine and TGF beta which help in the suppression of immune cells. A mutation in the gene that codes for Foxp3 has been notated to cause a severe and rapid autoimmune disorder called immune dysfunction. Hope you find this information helpful.