J. Castrop et al., CIRCUMVENTION OF TOLERANCE FOR THE NUCLEAR T-CELL PROTEIN TCF-1 BY IMMUNIZATION OF TCF-1 KNOCK-OUT MICE, Immunobiology, 193(2-4), 1995, pp. 281-287
Molecular events that underlie the well-defined phenotypic changes of
the differentiating thymocyte are poorly understood. A candidate gene
to control thymocyte differentiation, T cell factor-1 (TCF-1) encodes
a DNA-binding protein. Its mRNA expression pattern is complex during
embryogenesis, yet restricted to lymphocytes postnatally. Expression s
tudies on TCF-1 protein have been hampered by the difficulty to raise
antibodies due to extreme evolutionary conservation. TCF-1 knock-out m
ice, generated recently in our laboratory, have strongly decreased num
bers of thymocytes, but are otherwise normal. We have used these mice
to generate anti-TCF-1 antibodies. By immunization with a recombinant
fusion protein, we show that TCF-1 knock-out mice readily yield antise
rum titers against human and mouse TCF-1 protein. Wild-type littermate
s remain unresponsive to TCF-1 while they mount a high-titer antibody
response to the fusion protein, Maltose Binding Protein (MBP). Subsequ
ently, TCF-1-specific hybridomas could be prepared from the spleens of
immunized knock-out mice. This study illustrates the almost complete
tolerance of mice for human TCF-1 and demonstrates that this tolerance
is readily broken by gene knock-out. Furthermore, the usefulness of k
nock-out mice for the generation of monoclonal antibodies against the
gene product of interest is underscored.