Anti-CD41 Antibody [MEM-06] (Biotin) (A85934)

The co-localization of platelets and tumor cells in hematogenous metastases has long been recognized. Interactions between platelets and circulating tumor cells (CTCs) contribute to tumor cell survival and migration via the vasculature into other tissues. Taking advantage of the interactions between platelets and tumor cells, two schemes, direct and indirect, were proposed to target the modified human serum albumin submicron particles (HSA-MPs) towards tumor cells. HSA-MPs were constructed by the Co-precipitation-Crosslinking-Dissolution (CCD) method. The anti-CD41 antibody or CD62P protein was linked to the HSA-MPs separately via 1-ethyl-3-(-3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) EDC/NHS chemistry. The size of modified HSA-MPs was measured at approximately 1 µm, and the zeta potential was around -24 mV. Anti-CD41-HSA-MPs adhered to platelets as shown by flowcytometry and confocal laser scanning microscopy. In vitro, we confirmed the adhesion of platelets to tumor lung carcinoma cells A549 under shearing conditions. Higher cellular uptake of anti-CD41-HSA-MPs in A549 cells was found in the presence of activated platelets, suggesting that activated platelets can mediate the uptake of these particles. RNA-seq data in the Cancer Cell Lineage Encyclopedia (CCLE) and The Cancer Genome Atlas (TCGA) database showed the expression of CD62P ligands in different types of cancers. Compared to the non-targeted system, CD62P-HSA-MPs were found to have higher cellular uptake in A549 cells. Our results suggest that the platelet-based and platelet-mimicking modified HSA-MPs could be promising options for tracking metastatic cancer.

We recently reported that HLA-G1-transfected antigen-presenting cells (HLA-G1+ APCs) were capable of inhibiting alloproliferative responses. The aim of the present work was to further study the function and the mechanisms of action of HLA-G1+ APCs. We show here that HLA-G1+ APCs are immunoinhibitory cells that (i) inhibit the proliferation of CD4+ T cells, (ii) shed HLA-G1 molecules that might provide extra, non-antigen-specific, inhibitory or proapoptotic signals, (iii) induce CD4+ T cell anergy, or at least long-term unresponsiveness, and (iv) cause the differentiation of CD4+ T cells into suppressive cells. Thus, HLA-G+ APCs might (i) be involved in the direct suppression of immune responses and (ii) contribute to long-term efficient immune escape or tolerance.