Maturation of dendritic cell precursors into IL12-producing DCs by J-LEAPS immunogens

Abstract

LEAPS (ligand epitope antigen presentation system) vaccines consist of a peptide containing a major histocompatibility antigen binding peptide conjugated to an immune cell binding ligand (ICBL) such as the 'J' peptide from beta-2-microglobulin. Treatment of monocytes, monocytes plus GMCSF, or monocytes plus GMCSF and IL4 with JgD (containing a peptide from gD of herpes simplex virus type 1) or JH (with a peptide from HIV p17 gag protein) was sufficient to promote their maturation into Interleukin 12 producing dendritic cells. JgD-dendritic cells supported allotypic activation of T cells to produce Th1-related cytokines.

Fig. 1

Treatment with JgD or JH promotes maturation of human monocytes into dendritic cells. Monocytes obtained by leukapheresis of blood and purified by elutriation were cultured in serum free media + GMCSF and IL4 for 24 h. The cells were then treated with 14.5 µmol of JgD or JH and incubated for 3 days at 37°C. (A) Microscopic photographs of human monocytes show the phenotypic changes after treatment including dendrite formation and clustering of the cells. (B) Cells shown were fixed, stained with PE-anti-CD86 or PE-anti-DR and analyzed by flow cytometry.

Fig. 2

Survey of cytokine production following JgD or JH treatment. Human blood derived monocytes were treated with JgD or JH in two separate experiments. Spent media were collected three days post treatment, and evaluated by protein array (RayBio^® Human Cytokine Antibody Array 3). Array results were quantitated by densitometry, and normalized to the summation values for each array to allow for comparative analysis of JgD or JH treated to untreated dendritic cell array results. The data shown are the mean scores for the fold increase or decrease to the untreated control for each of the 42 cytokines on the replicated arrays. The error bars represent the standard deviation between trials. Inset, human monocytes from different donors produced similar amounts of IL12p70 after being treated with JgD. Spent media was obtained from monocytes from donors 3, 5, and 8 after incubation with JgD in separate and repeated experiments, and analyzed, as discussed above. (*) Significant change in cytokine production from untreated cells.

Fig. 3

JgD treated human monocytes activate allogeneic T cells to produce IFNα and IL2. Monocytes and T cells were obtained after elutriation of the human apheresis product. CD4⁺ T cells were further purified with T cell isolation columns. Monocytes harvested 24 h after treatment with JgD or HBSS were added to T cell cultures at a 1 DC: 10 T cell ratio. Spent media were collected six days after co-culture, and assayed by protein array as described above. (*) Significant change in cytokine production from untreated cells.