Chronic lymphocytic leukemia (CLL) is the most common form of leukemia that affects B lymphocytes in adults. Natural killer (NK) cells in CLL patients are intrinsically potent but display poor in situ effector functions. NKG2D is an activating receptor found on NK and CD8 C T cells and plays a role in immunosurveillance of CLL. In this study, we developed mono-and dual-targeting triplebodies utilizing a natural ligand for human NKG2D receptor (ULBP2) to retarget NK cells against tumor cells. Triplebodies in both formats showed better ability to induce NK-cell-dependent killing of target cells compared to bispecific counterparts. A mono-targeting triplebody ULBP2-aCD19-aCD19 successfully triggered NK cell effector functions against CLL cell line MEC1 and primary tumor cells in allogenic and autologous settings. Additionally, a dual-targeting triplebody ULBP2-aCD19-aCD33 specific for two distinct tumor-associated antigens was developed to target antigen loss variants, such as mixed lineage leukemia (MLL). Of note, this triplebody exhibited cytotoxic activity against CD19/CD33 double positive cells and retained its binding features even in the absence of one of the tumor antigens. Further, ULBP2-aCD19-aCD19 showed significant in vivo activity in immune-deficient (NSG) mouse model transplanted with CLL cell line as target cells and human immune cells as an effector population providing a proof-of-principle for this therapeutic concept.

PDT after i.v. verteporfin injection can selectively regress pre-existing corneal blood vessels or both blood and lymphatic vessels depending on the timing of PDT after verteporfin injection. The pretreatment of recipients with PDT and i.v. verteporfin might be a promising new method to improve graft survival in high-risk eyes.

Citation: Bock F, Onderka J, Braun G, et al. Identification of novel endogenous anti(lymph)angiogenic factors in the aqueous humor. Invest Ophthalmol Vis Sci. 2016;57:6554-6560. DOI: 10.1167/iovs.15-18526 PURPOSE. The avascular cornea is in direct contact with aqueous humor (AqH). Here we investigate whether AqH exerts anti(lymph)angiogenic effects and thereby may contribute to corneal (lymph)angiogenic privilege.METHODS. Using the murine model of suture-induced inflammatory corneal hem-and lymphangiogenesis, the potential anti(lymph)angiogenic effect of AqH was analyzed by applying murine AqH as eyedrops. Anti(lymph)angiogenic effects were measured using morphometric analysis of flat mounts stained with CD31 as panendothelial and LYVE-1 as specific lymphatic endothelial marker. The potential antilymphangiogenic effect of immunomodulatory factors contained in AqH such as vasoactive intestinal peptide (VIP) and a-melanocyte stimulating hormone (a-MSH) was analyzed in lymphatic and blood vascular endothelial cell proliferation assays in vitro.RESULTS. Topically applied AqH significantly inhibited corneal hemangiogenesis and even more so lymphangiogenesis in vivo and directly in vitro. The immunoregulatory factors VIP and a-MSH significantly inhibited lymphatic endothelial cell proliferation in vitro. Depletion of VIP or a-MSH from AqH diminished its anti-hem-and lymphangiogenic potential.CONCLUSIONS. Aqueous humor exerts significant antilymphangiogenic effects in vivo. This is at least partially mediated by the known immunomodulatory factors VIP and a-MSH present in the AqH. Therefore, AqH not only contributes to corneal lymphangiogenic privilege and is a new tool to identify novel endogenous regulators of lymphangiogenesis but also may have therapeutic applications.

Pathological corneal hem- and lymphangiogenesis are prime risk factors for corneal graft rejection. Fine needle-diathermy (FND) is an option to regress corneal blood vessels; however, whether this treatment besides clinically visible blood vessels also affects invisible lymphatic vessels is so far unknown. Here we test the hypothesis that FND destroys not only blood but also lymphatic vessels, thereby promotes corneal high-risk graft survival. The effect of FND was studied in vivo using BALB/c mice and the model of suture-induced corneal neovascularization. Mice were divided into three groups: FND, ANTI (anti-inflammatory therapy) and NON (control). Five, 7, 10 and 20 days after cauterization, corneas were harvested and stained with LYVE-1, CD31 to quantify (lymph)angiogenesis. The long-term survival of allografts was compared between the three groups. FND caused significant regression of both blood and lymphatic vessels compared to the control group at all time points (p < 0.05) with the most obvious effect at day 7 (p < 0.01). Graft survival was significantly prolonged when transplants were placed into the FND pretreated group (p < 0.0001). The effect of the anti-inflammatory therapy alone was less effective compared to FND (p < 0.05). This novel lymphangioregressive effect of FND can be used clinically to precondition high-risk recipients to promote graft survival.

Indirect immunofluorescence studies were compared with conventional smear cytology in 82 paired bone marrow samples from children with neuroblastoma using monoclonal antibodies (MAbs) BW 575 (neuroblastoma-associated 95 kD glycoprotein) and BW 625 (ganglioside GD2) and tetanus toxin labeling. Congruent results were obtained in 70 of 82, or 85% (positive/positive; negative/negative). In 12 of 82 (15%) patients, bone marrow infiltration was demonstrated by immunofluorescence but not by conventional cytology. As few as 0.01% neuroblastoma cells were reliably detected--in some cases even fewer. Because of antigen heterogeneity, false negative results were obtained in five cases with MAb BW 625, in two cases with MAb BW 575, and in no case with tetanus toxin. No antibodies showed any cross-reactivity to hematopoietic cells in either bone marrow of infants or during regeneration after chemotherapy. We conclude that this panel of antibodies is highly sensitive and specific to detect minimal disease in bone marrow of neuroblastoma patients, which has major implications for the staging procedure, monitoring treatment, early detection of relapse, and assessment of bone marrow status before autologous bone marrow transplantation.