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- Title
Increase in Regulatory T Cells in Dogs with Cancer Undergoing Chemotherapy.
- Authors
Biller, B. J.; Walter, C. U.; Lana, S. E.; Dow, S. W.
- Abstract
Regulatory T cells(Treg) are a naturally occurring population of T cells phenotypically identified by co-expression of CD4 and the IL-2 receptor(CD25). Theyplay a critical role in the control of tolerance and autoimmunity and have also been implicated in impairment of anti-tumor responses. We hypothesized that levels of Treg would be higher in cancer-bearing dogs than in normal dogs and that they would decrease with chemotherapy.Serial PBMC were isolated from twenty cancer-bearing dogs receiving either single-agent doxorubicin or the Madison-Wisconsin protocol. The following time points were studied: pre-treatment, day 2, week 1, week 3, 3 months and 6 months after initial treatment. Ten age-matched, normal dogs were also studied. PBMC were immunostained with directly conjugated antibodies to CD4, CD8, CD44 and IL-2 receptor and then evaluated by flow cytometry.Low numbers of lymphocytes with the CD4+/IL-2R+ phenotype were detectable in both normal and cancer-bearing dogs. A statistically significant increase in the percentage of IL2-R+/CD4+ T cells was observed in the cancer-bearing dogs beginning two days after chemotherapy and persisting throughout treatment. The percentage of IL-2R+/CD4+ T cells was also increased in pre-treated cancer-bearing dogs compared to control dogs.The percentage of IL-2R+/CD4+ T cells was generally higher in dogs with cancer than in healthy dogs. Unexpectedly, the percentage of IL-2R+/CD4+ cells increased during chemotherapy which suggests that chemotherapy may exert immunosuppressive effects through a previously undescribed mechanism. The identity of these CD4+/IL-2R+ T cells as true Treg awaits additional characterization studies.
- Subjects
CANCER; T cells; AUTOIMMUNITY; LABORATORY dogs; DRUG therapy; CYTOMETRY
- Publication
Veterinary & Comparative Oncology, 2005, Vol 3, Issue 1, p41
- ISSN
1476-5810
- Publication type
Article
- DOI
10.1111/j.1476-5810.2005.0064o.x