Project: Research project

Project Details


Development of long term marrow cultures which form osteoclast-like
multinucleated cells (MNC) from mononuclear precursors, has allowed us to
characterize the mechanism of action of osteotropic factors which regulate
osteoclast formation. Although these culture systems have been extremely
useful for these studies, they are limited by the fact that they are
composed of heterogeneous cell populations, making it impossible to
determine: 1) the molecular mechanisms involved in the differentiation of
osteoclast precursors to mature osteoclasts, 2) the identity of the
osteoclast precursor(s), or 3) if osteotropic factors act directly on
osteoclast precursors. Such studies require purified populations of
osteoclast precursors. To overcome these limitations, we have recently
developed monoclonal antibodies to these MNC. The monoclonal antibodies
react with a subpopulation of marrow mononuclear cells and freshly isolated
osteoclasts from fetal baboons as well as MNC, suggesting that they may
react with MNC precursors. The antibodies do not cross-react with
peripheral blood monocytes or macrophage polykaryons demonstrating that
they are not directed against macrophage antigens. With development of
these reagents we can no initiate studies to purify and characterize
osteoclast precursors. In this proposal we will: 1) further characterize
these newly developed anti-MNC monoclonal antibodies and test their ability
to purify osteoclast precursors from human bone marrow. If purified
populations of MNC precursors are obtained, we will use these purified
precursor populations to identify the cell lineage of the osteoclast by
determining the antigenic phenotype of the osteoclast precursor(s) and
determine the effects of osteotropic factors on purified populations of
osteoclasts precursors. 2) extend our culture studies in which we have
developed semi-solid culture systems which permit the clonal growth of
committed osteoclast (OCL) precursors. These clones will be used to raise
monoclonal antibodies against the committed OCL precursor. These
antibodies should be useful in purification of OCL precursors and
identification of unique differentiation antigens present on early OCL
precursors ; 3) transfect human marrow cell populations containing OCL
precursors with recombinant adenoviruses to determine if OCL precursors can
be transformed, and identify the growth conditions required for their
maturation to osteoclasts.
Effective start/end date9/1/858/14/95


  • National Institutes of Health
  • National Institutes of Health: $131,121.00
  • National Institutes of Health: $106,728.00
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health
  • National Institutes of Health


  • Medicine(all)


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