Appeal No. 2005-1511
Application No. 09/879,398
We have carefully considered the respective positions of both the
appellant and the examiner and find ourselves in substantial agreement with that
of the appellant. Accordingly, we reverse.
Background
The present invention is directed to the treatment of acute lymphoblastic
leukemia using a selected population of white blood cell (lymphocyte) known as
γδ+ T cells. Prior to the present invention, it was known in the art that
Lymphocytes are short-lived cells produced from bone marrow
stem cells that give rise to B cells, T cells and natural killer (NK) cells, in
addition to all other blood cells. A key feature of stem cells is their ability
to provide a constant source of progenitor cells that possess a high
proliferative capacity, but are committed to produce cells of one or more
blood cell lineage. Cells of the immune system are collectively referred to
as lymphoid cells and are believed to be descended from a common
lymphoid progenitor cell. [Bell, p. 2, para. 1].
With respect to T cells in particular, it was also known by prior
investigators that they
. . . recognize antigenic determinants through a surface receptor called the
T cell receptor (TcR). . . . T cells mediate their prime immunological
function through direct contact with infected host cells. These infected
cells cooperate by displaying (presenting) antigenic fragments of foreign
proteins on their surface as a means of signaling to T cells that they are
infected. While T cells recognize antigens presented on all host cells, T
cells are first activated to recognize these antigens by specialized antigen-
presenting cells such as dendritic cells, B cells and macrophages. . . .
Together with macrophages, T cells are the main component of the cell-
mediated immune response and, through the release of soluble factors,
are required for virtually all aspects of the immune response. In addition
to the T cell receptor, T cells are characterized by two major T cell-specific
surface markers, CD4 and CD8, which define functionally distinct T cell
populations. CD4 T cells, called T helper cells, are activated through
interaction with antigen-presenting cells and function primarily to activate
CD8 T cells, also known as cytotoxic or killer T cells (CTL). CTLs are the
main effector T cell mediating the destruction of infected host cells and
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