부산대학교 도서관

The CD4 molecule is the primary target for HIV, the AIDS virus. Cells, such as some human T cells, which express this protein on their cell surface are candidates for infection. A molecule of the virus, gp120, binds to the CD4 molecule, thereby attaching the virus to the cell and beginning the process of infection. However, it has become clear that some human cells which do not have the CD4 molecule may still become infected with HIV. Though the infectious process is less efficient in the cells which do not have CD4, it is nonetheless important to identify how the virus gets into these cells. Cells which do not express the CD4 receptor but which can become infected by HIV include brain cells. One method of determining which of the myriad of molecules on the surface of the cell serves as the binding point for HIV is by using specific antibodies. The rationale is simple: if an antibody binds to a specific molecule, it may then serve as a shield which blocks the binding of virus. If the molecule is uninvolved in the binding of virus, the presence of an antibody may have no effect. Using a panel of antibodies binding to different molecules, researchers found that antibodies to galactosyl ceramide inhibit the binding of HIV to the target cell. Galactosyl ceramide (GalC) is a glycolipid. The cell membranes of nerve cells contain many highly specialized molecules, which include a variety of glycolipids. Glycolipids are fatty substances which have been chemically modified by the addition of complex sugars to their molecular structure. It is these complex sugars which are responsible for the binding of specific antibodies and, very likely, the binding of HIV to GalC as well. The researchers confirmed that GalC has the necessary properties to serve as a virus receptor by demonstrating that when the glycolipids of nerve cells are separated in the analytical laboratory, the viral protein gp120 binds to GalC but not to the other glycolipids tested. (Consumer Summary produced by Reliance Medical Information, Inc.)