T cells in cryptopatch aggregates share TCR gamma variable region junctional sequences with gamma delta T cells in the small intestinal epithelium of mice.
The role of cryptopatch aggregates in the development of intestinal intraepithelial lymphocytes (IEL) is a matter of controversy. Therefore, an important question is whether T cells in cryptopatch aggregates are lineally related to IEL. We hypothesized that if gammadelta+ IEL derive from T cells in cryptopatch aggregates, then a clonal relationship would exist between the two populations. To test this hypothesis, we compared the sequence of rearranged TCR gamma variable region 5 genes in gammadelta+ IEL and cryptopatch cells. We purified IEL by FACS and cryptopatch cells were isolated from frozen sections of the intestine by laser-assisted microdissection. PCR showed that TCR gamma variable region 5 was rearranged in gammadelta+ IEL and in CD3+ cryptopatch cells, but not in CD3- cryptopatch cells. DNA sequence analysis showed that the frequency of in-frame junctions in cryptopatch aggregates was at a level consistent with positive selection in both wild-type and athymic nude mice. In addition, the predicted amino acid sequences of V-J junctions present in gammadelta+ IEL and cryptopatch cells were encoded by identical nucleotide sequences. By contrast, the frequency of in-frame joints was significantly reduced in cryptopatch cells isolated from TCR delta-deficient mice, indicating that the enrichment of in-frame joints in cryptopatch cells must normally depend on expression of surface gammadelta TCR. Our results are consistent with the hypothesis that a subset of gammadelta+ IEL are related to T cells in cryptopatch aggregates. The precise role of cryptopatch aggregates in intestinal gammadelta+ T cell homeostasis still needs to be determined.
Podd
Bradley S
BS
Department of Pediatrics, University of Virginia Health Sciences Center, Charlottesville, VA 22908, USA.
Thoits
Joseph
J
Whitley
Nicholas
N
Cheng
Hao-Yuan
HY
Kudla
Kimberly L
KL
Taniguchi
Hiroko
H
Halkias
Joanna
J
Goth
Kerstin
K
Camerini
Victoria
V
D000818:Animals; D017252:CD3 Complex / Q000096:biosynthesis; D002449:Cell Aggregation / Q000276:immunology; D002469:Cell Separation; D005091:Exons / Q000235:genetics; D005260:Female; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D007413:Intestinal Mucosa / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D007421:Intestine, Small / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D007834:Lasers; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008819:Mice, Nude; D042282:Microdissection; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology / Q000378:metabolism
D017252:CD3 Complex; D016692:Receptors, Antigen, T-Cell, gamma-delta