Regulatory T‐cells suppress the overstimulation of immune system; Helper T‐cell, for example, CD4+T regulate the adaptive immune response, especially B‐cells and macrophages; cytotoxic T‐cell, for example, CD8+ bind and lyse infected cells; memory T‐cells remain and circulate after infection to ensure rapid response to reinfection.[35, 37, 48]. Here, CD4 is linked to infection.