Autor/es:
SANCHEZ VALLECILLO, MARÍA FERNANDA; PALMA, SANTIAGO; ULLIO GAMBOA, GABRIELA; ALLEMANDI, DANIEL; MORÓN, GABRIEL; PISTORESI, MARÍA CRISTINA; MALETTO, BELKYS
Resumen:
CpG-ODN has successfully used as vaccine adjuvant but unfortunately has a reduced bioavailability. In order to
improve their bioavailability we have used CpG-ODN formulated in a nanostructure of 6-O- ascorbyl palmitate (Coa-ASC16),
which has the ability to form supramolecular aggregate that are produced by phase cooling below a critical micellar
temperature. Previously, we have observed that this strategy increased the bioavailability considering that improved the
CpG-ODN adjuvant activity. However, we still ignore the mechanisms by which Coa-ASC16 works. Perhaps more than one
factor could be synergistically contributing. Here, we tested whether Coa-ASC16 ?per se? is able to stimulate immune
system. Mice were i.p. injected with Coa-ASC16 or without Coa-ASC16 (control group). Coa-ASC16 induced a recruitment
of neutrophils (Ly6Ghigh, F4/80-, CD11b+, Ly6C+) (23±8 vs control:0.06±0.09 % after two hours injection p<0.05) and
inflammatory monocytes (Ly6Chigh, Ly6G-, F4/80-, CD11b+) (25±3 vs control:3±1 % after six hours injection p<0.05) into
the peritoneal cavity. We also observed production of IL-6 (ng/ml, 0.8±0.4 vs control:0.07±0.02 after two hours injection
p<0.05) in macrophages, neutrophils and inflammatory monocytes. These experiments were also carried out in TLR4-/-
animals obtaining the same result. In addition, we evaluated the levels of LDH, ALT and AST enzymes released into the
peritoneal lavage to assess cell damage/lysis. Coa-ASC16 induced an increase of levels of these enzymes two hours after
injection: LDH (U/l) (7100±1600 vs control: 1400±780 p<0.001), AST (U/l) (230±74 vs control:37±12 p<0.001), ALT (U/l)
(92±38 vs control:19±7 p<0.005). These observations suggest that one of the factors by Coa-ASC16 may enhance the
effect of CpG-ODN is the recruiting of innate immune cells to the site of injection. Coa-ASC16 cause tissue damage at the
site of injection and then could act as ?endogenous danger signals? which may initiate a sterile inflammatory response.