... Cells Undergo Positive and Negative Selection • Positive Selection Ensures MHC Restriction • Negative ... ... Selection (Central Tolerance) Ensures Self-Tolerance • The Selection Paradox: Why Don\'t We Delete ... ... All Cells We Positively Select? ... ... Are Used to Detect the Presence of Viruses and of Antiviral Antibodies • Bacterial Agglutination Can ... ... Be Used to Detect Antibodies to Bacteria -- Antibody Assays Based on Molecules Bound to Solid-Phase ...