Am. J. Respir. Cell Mol. Biol.,
Volume 18, Number 3, March, 1998 370-383
T-Cell Repertoire in the Blood and Lungs of Atopic Asthmatics
before and after Ragweed Challenge
Vladimir V.
Yurovsky,
Els J. M.
Weersink,
Susan S.
Meltzer,
Wendy C.
Moore,
Dirkje S.
Postma,
Eugene R.
Bleecker,
and
Barbara
White
Department of Medicine, University of Maryland, Baltimore, Maryland; Department of Pulmonology, University Hospital,
Groningen, The Netherlands; and Medicine and Research Services, Veterans Affairs Medical Center, Baltimore, Maryland
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 V
and V
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 V and V 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 V21 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.
