“Humanized” Mice — A Model for Testing HIV Acquisition

Worldwide, HIV is usually transmitted by unprotected sexual contact. Women account for more than half of all new infections; most acquire the virus intravaginally. A major factor hindering progress in understanding and preventing HIV transmission is lack of an adequate animal model. Simian immunodeficiency virus (SIV) infection in macaques has been used in some investigations, but SIV is not identical to HIV in all aspects, and too few macaques are available for experiments. Might mice be used instead?

To find out, researchers implanted human fetal liver and thymus tissue, and then transplanted human hematopoietic stem cells, into SCID mice. These humanized bone marrow–liver–thymus (BLT) mice showed complete systemic reconstitution of all ma…