16. Section for Studies on Host-immune Response
The research activities currently being carried out in our section can be
divided into two areas. The first is the study of an oxido-reduction
enzyme, thioredoxin, a study that has continued since 1985. The second is
the establishment of several cell lines of extrathymic T lymphocytes by
transplanting surgical specimens of inflammatory breast cancer. This second
study is in a newly developing field.
Thioredoxin and Its Role in Cell Activation
Thioredoxin is an oxido-reducing enzyme and historically this molecule is
considered an essential molecule for DNA synthesis. For instance, it is
reported to be an activator of ribonucleotide reductase and a subunit of
the DNA polymerase of T7 phage. It was found that an Epstein-Barr
virus-positive B-cell line predominantly produces an IL-1-like growth
factor. In collaboration with Professor J. Yodoi's group at Kyoto
University, this factor was successfully purified, cloned and found to be a
human counterpart of thioredoxin according to the homology and highly
conserved region of the enzymatically active site. Recombinant human
thioredoxin was found to promote cell growth in synergy with several
cytokines, such as IL-1 and IL-2. The role of thioredoxin in the second
messenger signal transduction during the cell activation process has been
studied and this factor was found to promote the proliferation of human
B-cells through a protein kinase C-dependent mechanism.(202)
Development of T-cell Lymphomas of Extrathymic Origin after
Implantation of Human Inflammatory Breast Cancer in BALB/c Nude Mice
Five independent tumors developed in BALB/c nude mice after xenografting of
surgical specimens from five different inflammatory breast cancer patients.
Several analytical procedures indicated that these tumors are of mouse
origin. Histological examination revealed that the tumors of transformed
mouse cell lines had features of malignant lymphoma. Phenotypically, the
tumor cells expressed early T lymphocyte markers. This system might provide
a good model for studies in several areas: in vivo malignant
transformation, preferential metastasis to the organs and extrathymic
T-cell development.
List of papers
from this division
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