INDUCTION OF PULMONARY ALLERGIC RESPONSES BY ANTIGEN-SPECIFIC TH2 CELLS

The development of pulmonary allergic responses was examined in mice f ollowing pulmonary transfer of Ag (conalbumin) specific Th2 cells, The levels of serum-specific IgE, cellular infiltrates, airway mucus gobl et cells, and airway responsiveness were analyzed and compared with th ose in Ag-sensitized and -challenged mice, Pulmonary transfer of the c onalbumin-specific Th2 clone (D10) induced, in an Ag-specific manner, high levels of the Th2 cytokines IL-4 and IL-5 in the bronchoalveolar lavage fluids and mucosal eosinophils, concomitant with an increase in airway responsiveness, The D10 cell-induced responses were seen in th e absence of serum specific IgE, In the presence of Ag, the transferre d D10 cells not only remained in the lungs, hut also increased in numb er 72 h post-cell transfer, Although significantly higher levels of IL -4 and IL-5 in the bronchoalveolar lavage fluids were found in D10-tra nsferred mice, the levels of pulmonary eosinophilia, mucus goblet cell s? and airway responsiveness were significantly lower than those in Ag -sensitized and -challenged mice, These results demonstrate that altho ugh Ag-specific activation of Th2 cells at mucosal sites is able to me diate the recruitment of eosinophils and the subsequent induction of a irway hyper-responsiveness, the more severe pulmonary allergic respons es were observed only in mice sensitized and challenged with Ag.