T repertoire in asthmatic airways following exposure to allergen

The hypothesis of this proposal was that allergen challenge will alter the CD4+ T cell repertoire expressed in the lungs of atopic asthmatics. To test this, the T cell repertoire in the Mood and bronchoalveolar lavage (BAL) fluids from six allergic asthmatics was tested before and after segmental ragweed challenge. Analyses of cell numbers, differential, and T cell subsets in BAL fluids showed that ragweed challenge was associated with preferential homing of CD4+ T cells to the longs. RT-PCR was used to amplify TCR V gene transcripts from unfractionated, CD4+, and CD8+ T cells. Ragweed challenge did not change the levels of expression of 22 Va and 25 Vβ gene families in BAL T cells. TheclonalityofTceUs was estimated by analyzing the diversity of TCR V-(D)-J junctions! region lengths associated with each V gene family. Some V gene families became pligoclonal after ragweed challenge, developing a new pattern of oligoclonal junctional region lengths. As hypothesized, new oligoclonal changes in some V gene families were seen in isolated CD4+ BAL T cells. Unexpectedly, CDS- BAL T cells also showed oligoclonal changes in certain V gene families after allergen challenge. This was confirmed by DNA sequence analysis and was not seen in control donors challenged with ragweed. These findings show that ragweed challenge is associated with oligoclonal activation of both CD4+ and CD8+ T cells in the lungs. The antigen specificity and function of these oligoclonal CD8+T cells are currently being investigated.