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An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Chatham Island forget-me-not Myosotidium hortensia (Boraginaceae) is a monotypic genus endemic to the Chatham Islands of New Zealand. Myosotidium hortensia is threatened in its natural environment ...

Agonistic anti–4-1BB Ab is known to ameliorate experimental autoimmune encephalomyelitis. 4-1BB triggering typically leads to the expansion of CD8+ T cells, which produce abundant IFN-γ, and this in turn results in IDO-dependent suppression of autoimmune responses. However, because neutralization of IFN-γ or depletion of CD8+ T cell only partially abrogates the effect of 4-1BB triggering, we sought to identify an additional mechanism of 4-1BB–triggered suppression of autoimmune responses using IFN-γ- or IFN-γR–deficient mice. 4-1BB triggering inhibited the generation of Th17 cells that is responsible for experimental autoimmune encephalomyelitis induction and progression, and increased Foxp3+CD4+ regulatory T (Treg) cells, particularly among CD4+ T cells. This was not due to a direct effect of 4-1BB signaling on CD4+ T cell differentiation: 4-1BB signaling not only reduced Th17 cells and increased Treg cells in wild-type mice, which could be due to IFN-γ production by the CD8+ T cells, but also did so in IFN-γ–deficient mice, in that case by downregulating IL-6 production. These results show that although secondary suppressive mechanisms evoked by 4-1BB triggering are usually masked by the strong effects of IFN-γ, 4-1BB signaling seems to modulate autoimmune responses by a number of mechanisms, and modulation of the Th17 versus Treg cell balance is one of those mechanisms.

Stimulation of 4-1BB (CD137) was shown to produce strong anticancer effects in vivo. In contrast, 4-1BB–deficient (4-1BB−/−) B6 mice are remarkably resistant to tumor growth. We set out to determine the mechanisms involved in these seemingly contradictory observations. We found that the therapeutic effects of 4-1BB triggering were mainly dependent on CD8+ T cells and partially on NK cells, whereas CD8+ T and NK cells were equally needed to suppress tumor growth in 4-1BB−/− mice. Cellular analysis showed that the frequency and number of NK cells in the spleen and bone marrow were decreased by 4-1BB triggering but were increased in the absence of 4-1BB signaling in tumor-challenged mice. The 4-1BB–mediated downregulation of NK cell development was primarily dependent on IFN-γ, which was produced by peripheral CD8+ T and NK cells. The suppression of NK cell development by 4-1BB–mediated IFN-γ production occurred in the bone marrow. As 4-1BB signaling increased in the periphery, more CD8+ T cells but fewer NK cells contributed to the antitumor immunity. As 4-1BB signaling decreased, more NK cells participated in the antitumor immunity. We conclude that 4-1BB signaling results in a shift of the dominant type of immune cell in antitumor immunity from the innate NK cell to the adaptive CD8+ T cell and that the level of IFN-γ is critical for this 4-1BB–mediated shift.

4-1BB (CD137) is expressed on dendritic cells (DCs) and its biological function has remained largely unresolved. By comparing 4-1BB-intact (4-1BB+/+) and 4-1BB-deficient (4-1BB−/−) DCs, we found that 4-1BB was strongly induced on DCs during the maturation and that DC maturation was normal in the absence of 4-1BB. However, DC survival rate was low in the absence of 4-1BB, which was due to the decreased Bcl-2 and Bcl-xL in 4-1BB−/− DCs compared with 4-1BB+/+ DCs after DC maturation. Consistent with these results, 4-1BB−/− DCs showed an increased turnover rate in steady state and more severely decreased in spleen by injecting LPS compared with 4-1BB+/+ DCs. When OVA-pulsed DCs were adoptively transferred to recipient mice along with OVA-specific CD4+ T cells, 4-1BB−/− DCs did not properly migrate to the T cell zone in lymph nodes and poorly induced proliferation of CD4+ T cells, although both DCs comparably expressed functional CCR7. Eventually, 4-1BB−/− DCs generated a reduced number of OVA-specific memory CD4+ T cells compared with 4-1BB+/+ DCs. To further assess the role of 4-1BB on DC longevity in vivo, 4-1BB+/+ and 4-1BB−/− C57BL/6 were administrated with Propionibacterium acnes that develop liver granuloma by recruiting DCs. Number and size of granuloma were reduced in the absence of 4-1BB, but the inflammatory cytokine level was comparable between the mice, which implied that the granuloma might be reduced due to the decreased longevity of DCs. These results demonstrate that 4-1BB on DCs controls the duration, DC-T interaction, and, therefore, immunogenicity.

4-1BB (CD137), a member of the tumor necrosis factor receptor superfamily (TNFRSF), is primarily expressed on activated T cells and is known to enhance proliferation of T cells, prevent activation-induced cell death, and promote memory formation of CD8(+) T cells. In particular, it is well acknowledged that 4-1BB triggering preferentially enhances the expansion of CD8(+) T cells rather than CD4(+) T cells, but the underlying mechanism remains unclear. Here we found that 4-1BB triggering markedly increased IL-2R alpha (CD25) and IL-2 expressions of CD8(+) T cells but minimally for CD4(+) T cells. Proliferation of CD8(+) T cells was moderately enhanced by direct 4-1BB triggering in the absence of signaling through IL2R alpha/IL-2 interactions, but further promoted in the presence of IL-2R alpha/IL-2 interactions. Among the TNFRSF members including OX40, GITR, CD30, and CD27, 4-1BB was superior in the ability to induce IL-2Ra expression on CD8(+) T cells. When the primary and secondary expansions of CD8(+) T cells in vivowere examined by adoptively transferring OVA-specific CD8(+) T cells along with the treatment with agonistic anti-4-1BB and/or antagonistic anti-CD25 F(ab') 2 mAb, 4-1BB triggering enhanced both primary and secondary expansion of CD8(+) T cells in vivo, and the 4-1BB effects were moderately suppressed in primary expansion while completely abolished in secondary expansion of OVA-specific CD8(+) T cells by blocking IL-2R alpha. These results suggest that 4-1BB-mediated increases of IL-2R alpha and IL-2 prolong the effects of transient TCR- and 4-1BB-mediated signaling in CD8(+) T cells, and that 4-1BB triggering preferentially enhances the expansion of CD8(+) T cells through the amplification of autocrine IL-2/IL-2R signaling loop.

Adoptive T-cell therapy is a promising approach to the immunotherapy of cancer, but for it to be a general cancer therapy a simple and standardized procedure for producing tumor-specific CD8 T cells is needed. On the basis of a unique property of 4-1BB (CD137), the selective expression on activated T cells, we have developed a simple and practical protocol to produce antigen-specific CD8 T cells from peripheral blood mononuclear cells. We have proved the feasibility of this procedure by isolating and expanding cytomegalovirus-specific CD8 T cells, and applied the procedure to produce Epstein-Barr virus (EBV)-specific CD8 T cells. By using this procedure, we could readily produce 10-10 antigen-specific CD8 T cells from 30 to 50 mL of blood in about 4 weeks. Moreover, our protocol allowed us to produce, from solid cancer patients, CD8 T cells that were specific for self/tumor antigens such as human telomerase reverse transcriptase (hTERT). It is interesting to note that, we were unable to amplify hTERT-specific CD8 T cells from healthy donors. Our protocol can be readily translated into cGMP-compliant production and is currently being used to produce EBV-specific CD8 T cells for phase I clinical trial. We believe that our method will provide a practical and effective option for adoptive T-cell therapy in the clinic.

While most of the existing depth recovery methods compute 2 1 2 -D depth information from 2-D intensity images, the method described in this paper recovers the cross-section of a scene by processing the line images of a line scan camera. This method has some advantages as compared to the existing stereo methods. Line images, which are combined to make a slit image, are taken by moving the line scan camera along a linear rail. The depth of a pixel is directly related to the slope of a straight line in the slit image. Thus one of the advantages is that correspondence becomes the problem of detecting straight lines in the slit image. Another advantage is that we can obtain very high resolution images if we use a line scan camera, since it is not difficult to find CCD sensors with 4 k or more linear arrays in the market. Hough transforms are used to find straight lines in the slit image. Instead of the number of points on a line, each cell in Hough space records the intensity variation of the pixels on a line. We derive the mathematical background of this method and show some experimental results with several real images. This scheme has a important potential for industrial and scientific application capability with greater refinement.

A method of calculating the locations of fixed points on a cross-section of a 3D object is described. Line images of a rotating object are merged to form a 2D angle-space image. Edge points from this are used to find the cross-sectional locations of feature points that are fixed on the surface of the object.