In vitro analysis of the first steps of immune stimulation elicited by CSF-470 vaccine plus adjuvants

PAMPENA, MARÍA BETINA; JULIÁ, ESTEFANÍA PAULA; BLANCO, PAULA ALEJANDRA; BARRIO, MARÍA MARCELA; MORDOH, JOSÉ; LEVY, ESTRELLA MARIEL

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS; 2017

SOCIEDAD ARGENTINA DE INVESTIGACIÓN CLÍNICA; SOCIEDAD ARGENTINA DE INVESTIGACIÓN BIOQUÍMICA Y BIOLOGÍA MOLECULAR; SOCIEDAD ARGENTINA DE INMUNOLOGÍA;

In a Phase II/III randomized clinical trial (CASVAC-0401,NCT01729663), thirty post-surgery stages II/III cutaneous melanoma(CM) patients (pts) received CSF-470 vaccine or IFN-α2b (2:1).The CSF-470 vaccine is a mini-allograft of four lethally-irradiatedallogeneic CM cell lines (CSF-470 cells), with BCG and rhGM-CSFas adjuvants. Since immune monitoring demonstrated an increasein anti-tumor innate and adaptive immunity of vaccinated pts, weattempted to investigate the first steps of the immune response elicitedby CSF-470 vaccine plus adjuvants. Using an in vitro modelof healthy donors? mononuclear peripheral blood cells (HD PBMC)in coculture with CSF-470 cells (1:1 PBMC:CSF-470 cells, 0,5x106each) plus adjuvants, early release of TNF-α (6 hs, 340.5±191.3pg/ml) and IL-1b (48 hs, 456.3±195.3 pg/ml) were detected. WhenHD PBMC were stimulated only with adjuvants, TNF-α and IL-1β release was higher (TNF-α: 1059±470 pg/ml; IL-1β: 1650±555 pg/ml). CSF-470 cells RNAseq analysis revealed an anti-inflammatoryexpression pattern, including TGF-β and IL-10 overexpression, thatcould partially mediate the hampered cytokines production, mainlypromoted by BCG. On the other hand, IFN-γ release was alsodetected, but only in some HD PBMC with CSF-470 cells plus adjuvantscocultures (48 hs, 226,6±150 pg/ml), thus showing a highdependency on HD PBMC response to BCG. In conclusion, adjuvants,mainly BCG, were required to induce local inflammation inthe presence of CSF-470 vaccine cells, given the anti-inflammatorypattern of cytokine expression, thus helping to create a favorablecontext for vaccine antigens to be processed and present.