Anti-Human CD84 Polyclonal antibody

In murine models, transgenic chemokine-cytokine tumor vaccines overcome many of the limitations of single-agent immunotherapy by producing the sequence of T-cell attraction followed by proliferation of tumor antigen-activated clones. The safety and immunologic effects of this approach in humans were tested in 7 patients with relapsed or refractory neuroblastoma. They each received up to 8 subcutaneous injections of a vaccine combining lymphotactin-and interleukin-2 (IL-2)-secreting autologous neuroblastoma cells in a close-escalating scheme. Adverse events were limited to grade 1 or 2 localized reactions in all patients, pain in 3 patients, and fever in 3 patients. Injection site biopsies revealed increased cellularity caused by infiltration of CD4(+) and CD84(+) lymphocytes, eosinophils, and dendritic cells with a decrease in dendritic cells from the first to the second vaccination. Systemically, vaccine was associated with increased tumor recognition Lis measured by enzyme-linked immunosorbent spot assays. Two patients had interferon-gamma predominant responses and 3 had IL-5 predominant responses. Only 1 patient received all 8 injections, 1 patient stopped the study early, and all other patients progressed before completion of the study. Hence, autologous turner cell vaccines combining transgenic lymphotactin with IL-2 seem to have little toxicity in humans and can induce an antitumor immune response. In this setting, the immune response wits insufficient to overcome active recurrent neuroblastoma.

Rationale: Ischemic stroke is a leading cause of morbidity and mortality worldwide. Recanalization of the occluded vessel is essential but not sufficient to guarantee brain salvage. Experimental and clinical data suggest that infarcts often develop further due to a thromboinflammatory process critically involving platelets and T cells, but the underlying mechanisms are unknown. Objective: We aimed to determine the role of CD (cluster of differentiation)-84 in acute ischemic stroke after recanalization and to dissect the underlying molecular thromboinflammatory mechanisms. Methods and Results: Here, we show that mice lacking CD84-a homophilic immunoreceptor of the SLAM (signaling lymphocyte activation molecule) family-on either platelets or T cells displayed reduced cerebral CD4(+)T-cell infiltration and thrombotic activity following experimental stroke resulting in reduced neurological damage. In vitro, platelet-derived soluble CD84 enhanced motility of wild-type but not ofCd84(-/-)CD4(+)T cells suggesting homophilic CD84 interactions to drive this process. Clinically, human arterial blood directly sampled from the ischemic cerebral circulation indicated local shedding of platelet CD84. Moreover, high platelet CD84 expression levels were associated with poor outcome in patients with stroke. Conclusions: These results establish CD84 as a critical pathogenic effector and thus a potential pharmacological target in ischemic stroke.