In the CD4+ T cell response, S protein accounted for nearly 40% of the total CD4+ T cell response in individuals recovered from symptomatic infection, which was obviously higher than the CD4+ T cell response induced by M or N (39.1% vs 26.3%, P < 0.001; 39.1% vs 33.6%, P = 0.004). The gene discussed is CD4; the disease is infection.