CD4 and infection: As a result, it is not surprising that autophagy promoted MHC class II antigen presentation to CD4+ T cells in various infection models, such as modified vaccinia virus Ankara (13) or herpes simplex virus 1 (HSV-1) (14–17) or was able to enhance cytokine production by CD4+ T cells in Toxoplasma gondii (T. gondii) (18) or respiratory syncytial virus (RSV) infection (19).