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Granzyme (grz) AB−−H2bmice generate numerically normal cytotoxic T lymphocyte (CTL) responses to the prominent influenza A virus DbNP366and DbPA224epitopes and terminate the infectious process in the pneumonic lung with the same kinetics as the WT controls. Though grz B protein expression is fully compromised, there is only a partial effect on the level of CTL activity measured in a classical, short-term 51Cr release assay. Single-cell polymerase chain reaction (PCR) analysis of both highly activated effector and “resting” memory CD8T cells from influenza A virus–infected grzAB−−mice showed a high prevalence of grzK mRNAexpression in tetramer (tet)CTLs as was found in WT mice. However, a marked reduction in cytotoxicity present in the primary splenic CTLs of grzAB−−mice correlated with decreased grzK expression, as measured by real-time PCR. This suggests that grzK plays an important role in CD8T-cell cytotoxicity both in the presence and absence of grzA and B. [ABSTRACT FROM AUTHOR]

ABSTRACTHIN-200 proteins are interferon (IFN)-inducible proteins that can regulate cell proliferation and differentiation in vitro. Characterization of the lineage and cell type-dependent expression of Ifi202revealed little or no expression of Ifi202in the Lin−/c-Kitfraction enriched for immature hematopoietic progenitor cells (HPCs) but higher levels in more differentiated Lin−/c-Kit−and Linpopulations. The highest levels of Ifi202expression were observed in CD11b/Gr-1dimimmature granulocytes in the bone marrow. In the peripheral blood, Ifi202was expressed only in the myeloid lineage, with the highest level of expression seen in CD11b/Gr-1dimimmature granulocytes. Constitutive expression of p202 in primary HPCs delayed proliferation of these cells in vitro, caused a reduction in the number and size of myeloid colonies growing on methylcellulose, and affected the ability of the cells to reconstitute irradiated mice but did not significantly affect cell differentiation. Thus, p202 plays a role in regulating the proliferative capacity of hematopoietic cells. [ABSTRACT FROM AUTHOR]