CD4 and HIV infectious disease: HS GAGs Syndecan-4 (in cis) HA of Influenza virus HN of avian Newcastle disease virus, Sendai virus and human parainfluenza virus PDGF-DD Nidogen-1 PCNA NKp44L expressed on tumor cells, bystander CD4+ T cell during HIV infection, or cartilage-derived chondrocytes Domain III envelope protein from West Nile and Dengue viruses Unknown ligand(s) on Mycobacterium tuberculosis, M. bovis, Nocardia farcinica and Pseudomonas aeruginosa