T-Cell repertoire in the blood and lungs of atopic asthmatics before and after ragweed challenge.
T cells play a pivotal role in initiating and orchestrating allergic responses in asthma. The goal of this work was to learn whether ragweed challenge in the lungs alters the T-cell repertoire expressed in the blood and lungs of atopic asthmatics. Analyses of cell numbers, differentials, and T-cell subsets in bronchoalveolar lavage (BAL) fluids showed that ragweed challenge was associated with preferential recruitment of CD4+ T cells into the lungs. A reverse transcriptase-polymerase chain reaction (RT-PCR) was used to amplify T-cell receptor (TCR) gene transcripts from unfractionated, CD4+, and CD8+ T cells in blood and BAL fluids. As judged by RT-PCR, the usage of TCR Valpha and Vbeta gene families in BAL fluids was similar to that in blood. Ragweed challenge did not change the levels of expression of these V gene families. The clonality of T cells was estimated by analyzing the diversity of TCR V-(D)-J junctional region nucleotide lengths associated with each Valpha and Vbeta gene family, using sequencing gel electrophoresis. Most V gene families in blood and BAL fluids were associated with multiple junctional region lengths before and after ragweed challenge, indicating polyclonal expression. Some V gene families were expressed in an oligoclonal manner in unfractionated, CD4+, and CD8+ T cells in BAL fluids before ragweed challenge, as indicated by a few predominant junctional region lengths. The majority of these V gene families became polyclonal after challenge, compatible with polyclonal T-cell influx during inflammation immediately after ragweed challenge. However, some V gene families became oligoclonal or developed a new oligoclonal pattern of junctional region lengths in BAL T cells after ragweed challenge. Surprisingly, this occurred in both CD4+ and CD8+ T cells. In one of these instances, DNA sequencing of Vbeta21 junctional regions in CD8+ T cells confirmed a change from polyclonal to oligoclonal expression after ragweed challenge. These findings show that ragweed challenge is associated with polyclonal influx and oligoclonal activation of both CD4+ and CD8+ T cells in the lungs.
Yurovsky
V V
VV
Department of Medicine, University of Maryland, Baltimore, Maryland 21201, USA. vyurovsk@umabnet.ab.umd.edu
Weersink
E J
EJ
Meltzer
S S
SS
Moore
W C
WC
Postma
D S
DS
Bleecker
E R
ER
White
B
B
D000328:Adult; D000485:Allergens / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000097:blood / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002415:Cats; D005260:Female; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000097:blood / Q000276:immunology*; D008168:Lung / Q000276:immunology*; D008297:Male; D008925:Mites / Q000276:immunology; D011058:Pollen / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013601:T-Lymphocytes / Q000276:immunology*
D000485:Allergens; D016693:Receptors, Antigen, T-Cell, alpha-beta