Role of intestinal T cells in pulmonary immunity to non-typable

Abstract

Intestinal T cells have been shown to be an important component of respiratory tract immunity in the rat. The role of these cells may be in part to influence the behaviour of lung polymorphs. Lymphocytes were collected from the thoracic duct of rats primed by intra-Peyer’s patch (IPP) inoculation with nontypable Haemophilus influenzae (NTHI). Initially, whole washed thoracic duct lymphocyte (TDL) populations were transferred to recipient rats. These rats cleared bacteria from bronchial spaces faster than non-transfused rats, and rats transfused with non-immune lymphocytes. Rats given a reduced number of lymphocytes did not clear NTHI faster than controls. When lymphocytes depleted of B cells were transferred, NTHI clearance rate was accelerated. Spleen cells were also capable of conferring protection to transfused rats. Polymorphs from immunised rats were shown to be recruited faster and have a higher activity level than non-immunised rats. Immunised nude rats are less able to accelerate clearance of NTHI. These data suggest that immune clearance of NTHI from the respiratory tract following gut immunisation is dependent upon antigen primed mucosal T cells which may modulate the function of lung polymorphs.