Rabbit Papilloma displays tropism for the cutaneous epithelium. AAV2 presents natural tropism towards skeletal muscles, neurons, vascular smooth muscle cells and hepatocytes. In the brain, most AAV serotypes show neuronal tropism, while AAV5 also transduces astrocytes. Most attempts to limit tropism have used chimeric envelope proteins bearing antibody fragments. One of the nucleotide mutations is in the process of glycoprotein formation and affects tropism. The term viral tropism refers to the cell types a virus infects. Bacterial adhesins provide species and tissue tropism. See HIV tropism and Replication cycle of HIV. After this mutation, the FCoV acquires a tropism for macrophages while losing intestinal tropism. The Trofile assay is used to determine HIV tropism. Acute infections have high morbidity and tropism for the salivary, lachrymal and harderian glands. This tropism is unique in that most respiratory viruses target ciliated cells. The precise molecular mechanisms mediating "Human polyomavirus 2" meningeal tropism remains to be found. HIV tropism of a patient's virus is measured by the Trofile assay. The term viral tropism refers to which cell types HTLV-I infects.