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Both peptidoglycan and muropeptides potently modulate inflammatory and innate immune responses. The secreted Listeria monocytogenes p60 autolysin digests peptidoglycan and promotes bacterial infection in vivo. Here, we report that p60 contributes to bacterial subversion of NK cell activation and innate IFN-gamma production. L. monocytogenes deficient for p60 (Deltap60) competed well for expansion in mice doubly deficient for IFNAR1 and IFN-gammaR1 or singly deficient for IFN-gammaR1, but not in wild-type, IFNAR1(-/-), or TLR2(-/-) mice. The restored competitiveness of p60-deficient bacteria suggested a specific role for p60 in bacterial subversion of IFN-gamma-mediated immune responses, since in vivo expansion of three other mutant L. monocytogenes strains (DeltaActA, DeltaNamA, and DeltaPlcB) was not complemented in IFN-gammaR1(-/-) mice. Bacterial expression of p60 was not required to induce socs1, socs3, and il10 expression in infected mouse bone marrow macrophages but did correlate with enhanced production of IL-6, IL-12p70, and most strikingly IFN-gamma. The primary source of p60-dependent innate IFN-gamma was NK cells, whereas bacterial p60 expression did not significantly alter innate IFN-gamma production by T cells. The mechanism for p60-dependent NK cell stimulation was also indirect, given that treatment with purified p60 protein failed to directly activate NK cells for IFN-gamma production. These data suggest that p60 may act on infected cells to indirectly enhance NK cell activation and increase innate IFN-gamma production, which presumably promotes early bacterial expansion through its immunoregulatory effects on bystander cells. Thus, the simultaneous induction of IFN-gamma production and factors that inhibit IFN-gamma signaling may be a common strategy for misdirection of early antibacterial immunity.

The roles of many non-oncogenic mutations in cancer may influence tumor growth, survival, or how tumors interact with their surroundings. Here we characterize the functional relevance of missense mutations within the gene encoding the tumor necrosis receptor family member HVEM (TNFRSF14), a locus frequently targeted within human lymphoma and other cancers. We find that point mutations identified in human lymphoma were localized to the extracellular domain and specifically target ligand binding, resulting in preferential loss of CD160 and BTLA interactions compared to LIGHT (TNFSF14). Missense mutations were associated with alterations in cytotoxic effector cell signatures within tumor biopsies, while deletion mutations were associated with changes in myeloid cell signatures. Finally, we find that mutated HVEM proteins retained the capacity to inhibit T cell signaling through BTLA, while reducing costimulation of cytolysis in NK cells through CD160. Together, these data provide evidence for how immune selective pressures may drive mutation of TNFRSF14 resulting in greater tumor fitness.

Tregs play a key role in immune system suppression during autoimmunity and tumor development. Tregs are classified as CD4+CD25+FoxP3+, and exist as either nTregs originating from the thymus, or iTregs derived from CD4+ effector T cells in the periphery. Reduction in Treg numbers leads to autoimmunity; this is clearly shown in scurfy mice where FoxP3 has been deleted, Treg numbers are severely reduced, and mice succumb to autoimmunity early in life. In contrast, Tregs play a debilitating role in cancer biology when the Treg numbers are elevated, and the immune response is dampened allowing cancer cells to evade the immune system. Thus, the correct balance of Tregs is essential for maintaining immune homeostasis. FoxP3 has been widely used as a marker of Tregs, and many antibodies are available on the market that distinguish the Treg population in human or mouse cells. We developed a novel FoxP3 antibody and Fix and Perm buffer system that is comparable to current clones, but recognizes both mouse and human FoxP3 equally well, eliminating the need for separate antibodies. The ms/hu FoxP3 antibody was generated using our Rabbit Recombinant antibody technology, which allows for selecting high specificity, high affinity antibodies, lot to lot consistency and detection of both mouse and human nTregs and iTregs. This allows researchers to extend their mouse models into clinical studies without a change in the antibody clone eliminating a variable and streamlining the process.