AUTHOR=Ha Ngoc , Pham Duc-Hung , Shahsafaei Aliakbar , Naruse Chie , Asano Masahide , Thai To-Ha 

TITLE=HP-1γ Controls High-Affinity Antibody Response to T-Dependent Antigens

JOURNAL=Frontiers in Immunology

VOLUME=5

YEAR=2014

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2014.00271

DOI=10.3389/fimmu.2014.00271

ISSN=1664-3224

ABSTRACT=<p><italic>In vitro</italic> observations suggest a role for the mouse heterochromatin protein 1γ (HP-1γ) in the immune system. However, it has not been shown if and how HP-1γ contributes to immunity <italic>in vivo</italic>. Here we show that in mice, HP-1γ positively regulates the germinal center reaction and high-affinity antibody response to thymus (T)-dependent antigens by limiting the size of CD8<sup>+</sup> regulatory T-cell (T<sub>reg</sub>) compartment without affecting progenitor B- or T-cell-development. Moreover, HP-1γ does not control cell proliferation or class switch recombination. Haploinsufficiency of <italic>cbx-3</italic> (gene encoding HP-1γ) is sufficient to expand the CD8<sup>+</sup> T<sub>reg</sub> population and impair the immune response in mice despite the presence of wild-type HP-1α and HP-1β. This is the first <italic>in vivo</italic> evidence demonstrating the non-redundant role of HP-1γ in immunity.</p>