ISB symposium: update 1

The first talk was by Irving Weissman, one of the pioneers in immunology and stem cell research. He talked about the stem cells that form blood, also known as HSCs or hematopoietic stem cells.

These cells are great because they can self-renew, and they can divide and differentiate. That is, they can form new kinds of cells. Weissman talked about experiments that were done at different companies, Systemix, Cellerant, Inc., and others with using stem cells to see if certain types of disease could be cured (in mice) by repopulating the mice with new stem cells.

Some interesting things -

- There are stem cells in the blood, over 30,000 of these cells go through the blood of a mouse every day. The bone marrow contains stem cells that recirculate throughout the body.

- Older mice have more stem cells and those stem cells give rise to different kinds of differentiated cells, when compared to younger mice. Myeloid genes are overexpressed and you get more myeloid cells.

- leukemias can occur because of events in stem cells. Activating events that lead to leukemias can occur at every stage of differentiation between a stem cell and the mature blood cell. They have found at least seven kinds of events. They were able to identify some of the molecular events by purifying the cells from the bone marrow.