3-Day monocyte-derived dendritic cells stimulated with a combination of OK432, TLR7/8 ligand, and prostaglandin E2 are a promising alternative for cancer immunotherapy.

Numerous trials using dendritic cell (DC)-based vaccinations for the treatment of cancer are being carried out. However, an improvement of the quality of DC used is highly warranted. We here generated human monocyte-derived dendritic cells using a 3 day protocol and stimulated the cells using a combination of OK432 (Picibanil), TLR7/8 ligand CL097, and reduced amounts of prostaglandin (PG)E2. We analyzed phenotype, migratory, and T-cell stimulatory capacity compared to a cytokine cocktail consisting of IL-1ß, IL-6, TNF, and PGE2. The OK432 cocktail stimulated cells had a similar mature phenotype with upregulated co-stimulatory molecules, HLA-DR and CCR7 as the cytokine cocktail-matured cells and a similar cytokine profile except increased amounts of IL-12p70. Chemotaxis towards CCL19 was reduced compared to the cytokine cocktail, but increased compared to OK432 alone. The T-cell stimulatory capacity was similar to the cytokine cocktail stimulated cells. In conclusion, the OK432 cocktail has the advantage of inducing IL-12p70 production without impairing phenotype or T-cell stimulatory capacity of the cells and might, therefore, be an advantageous alternative to be used in DC-based immunotherapy.

Low number of memory B cells in the salivary glands of patients with primary Sjögren's syndrome.

We have previously shown that patients with primary Sjögren's Syndrome (pSS) show a significant reduction of autoantigen specific CD27(+) memory B cells and an abnormally elevated level of autoantibody producing plasma cells in peripheral blood (PB) compared to controls. Because both memory B cells and plasma cells have been detected in salivary glands (SG) of pSS patients, we aimed to study the B cell pattern in SG biopsies. Double immunohistochemical staining of CD20 and CD27 was carried out on paraffin-embedded SG tissue from 10 pSS patients to distinguish CD20(+)/CD27(+) memory B cells, and identify the CD20(+) glandular B cell zones (BCZ). Given that plasma blasts and plasma cells are CD27(++) and CD20(- ), additional CD138 single staining of serial sections allowed the distinction of CD27(++)/CD138(- ) plasma blasts located within the BCZ from CD27(++)/CD138(+) plasma cells that were found mostly on the periphery of the BCZ and also observed interstitially. Both BCZ and the memory B cell populations were then quantified. Contrary to what has been reported earlier through immunoflourescent staining of memory B cells in SG tissue, we have shown that there is a low number of memory B cells located within the glandular BCZ. Plasma blasts and plasma cells, however, were more abundant in the SG. Together our findings suggest that these low numbers of memory B cells in both PB and SG of pSS patients may be the result of activation of these cells into plasma cells at the site of inflammation.