CD80 and CD86, which are costimulatory molecules in T-cell activation, play important roles in the differentiation of Th1- or Th2-phenotypes. The results of blocking studies using neutralizing antibodies have suggested that CD80 and CD86 also play important roles in sensitization to cedar pollen antigen, but very few studies have examined the kinetics of CD80 and CD86 expression on antigen-presenting cells (APC).
We studied the kinetics of CD80 and CD86 expression on APC after allergen-stimulation in cedar pollinosis subjects.
A skin-prick test was performed in nine subjects with pollinosis and seven control subjects. Peripheral blood mononuclear cells (PBMC) were isolated and stimulated with Japanese cedar pollen extract. Zero to 8 days following in vitro stimulation, the expression of CD80 and CD86 in either CD14_??_ or CD19_??_ cells was analyzed by two-color flow cytometry. The expression of CD28, CTLA-4 and CD40L on CD4+ cells was analyzed by two-color flow cytometry after elinminating either CD14+ or CD19+ cells.
After in vitro stimulation, the expression of both CD80 and CD86 was significantly upregulated in pollinosis subjects compared to control subjects. However, the difference was observed in the kinetics of CD80 and CD86 expression following allergen stimulation. The expression of CD86 was upregulated earlier than that of CD80 after in vitro stimulation. In the absence of CD19_??_ cells, the expression of CD28, CTLA-4, and CD4OL in CD4_??_ cells was significantly lower than that in the absence of CD14_??_ cells.
These results indicate that CD19+ cells of pollinosis subjects expressed higher CD80 and CD86 than that of control subjects, and that the kinetics of CD80 and CD86 expression following stimulation differed. In pollinosis subjects, CD19_??_ cells may thus function as APC in allergen-induced activation of PBMC.