Increased numbers of gamma-delta T cells in Heymann nephritis expressing Vgamma6 / Vdelta1 and showing a canonical restriction of the CDR3 region.

H Wu, SI Alexander and JF Knight

Centre for Kidney Research, The Children's Hospital at Westmead, Sydney, Australia

We have reported that the presence of gamma-delta T cells is associated with kidney damage in human IgA nephropathy and in a rat model of adriamycin (ADR) induced nephropathy. We have also shown that these T cells use a restricted set of gamma-delta T cell receptor (TCR) genes. This study examines whether T cells infiltrating the kidney also use a restricted set of gamma-delta T cell receptor genes in Heymann nephritis (HN), a rat model of autoimmune mediated glomerulonephritis.

HN was induced in Lewis rats by immunisation with renal tubular antigen (Fx1A) in CFA. Kidneys, spleen and lymph nodes were collected 8 and 12 weeks after immunisation. T cells were isolated from the kidney using a gradient separation method. Flow cytometry analysis (FACS) was used to determine the percentage of gamma-delta T cells as a proportion of the total number of CD3+ T cells. TCR V gamma-delta repertoire was measured by RT-PCR and sequencing was used to characterise the diversity of the CDR3 region of these receptors. Cytokine gene expression was measured by semiquantitative RT-PCR.

FACS of lymphocyte subpopulations using anti-CD3 and anti-gamma-delta TCR antibodies showed that gamma-delta T cells as a proportion of CD3+ cells were significantly increased in HN kidneys (6.9 ± 2.9%) but not in lymph nodes (1.6 ± 0.35%), (n = 8, p < 0.01). Analysis of the kidney TCR V gamma-delta repertoire showed that these cells predominantly expressed Vgamma6 / Vdelta1 genes. Sequencing analysis of the Vgamma6 / Vdelta1 junctional region showed that they used canonical sequences identical to those expressed on fetal thymocytes. RT-PCR for cytokine gene expression showed that gamma-delta T cells from the kidneys expressed significantly higher levels of IL-4 (p < 0.05) and IL-5 (p < 0.05) and significantly lower levels of IL-2 (p <0.05) compared to gamma-delta T cells from the lymph nodes.

These results demonstrate that the majority of gamma-delta T cells in the HN kidney use an invariant, canonical Vgamma6 / Vdelta1 TCR - exactly the same gamma-delta TCR we have previously described in the rat ADR kidney. These canonical Vgamma6 / Vdelta1 T cells may recognise an unknown common ligand expressed in the kidney in response to a wide variety of causes of chronic inflammation.

Presented at the Annual Scientific Meeting of the Australian and New Zealand Society of Nephrology, Darwin, September 2001
Presented at the ASN/ISN World Congress of Nephrology, San Francisco, October 2001

Correspondence:
Dr Huiling Wu
HuilW@chw.edu.au