CD 4 are associated with -

T cells can differentiate into effector cells. Helper (CD4) T-cell activity, in addition to stimulating B cells to produce antibodies, promotes the development of delayed hypersensitivity and thereby also serves in the defense against intracellular agents, including intracellular bacteria (eg, mycobacteria), fungi, protozoa, and viruses. Reff: Ananthanarayanan & Panikers textbook of microbiology 9th edition pg: 135