Central memory CD8+ T cells in tumor draining lymph nodes of breast cancer patients

Introduction & Aim: Long-lasting immune protection is achieved by the differentiation of naïve T cells upon antigen stimulation into memory cells consisting of central (TCM) and effector (TEM) memory cells. TCM cells highly express CCR7 and CD62L and circulate inside the lymphatic organs. They exhibit a relative high longevity and convert into more short-lived TEM cells. Present study aimed to determine the frequency of CD8+TCM cells in tumor draining lymph nodes (TDLNs) of breast cancer (BC) patients. Methods: Mononuclear cells were obtained from TDLNs of 52 untreated patients with BC and stained by anti-CD8,-CCR7,-CD45RO,-CD95 specific antibodies. Data were acquired on four-color flow cytometer and analyzed by CellQuest Pro software. Results: The frequency of total CD8+TCM cells was 33.84±2.16 in TDLNs of BC patients. Statistical analysis showed that the frequency of total TCM and their CD45ROLow subsets tended to increase in involved lymph nodes comparing to free ones (P<0.05). The MFI of CD95 on TCM, and on both CD45RO low and high expressing subsets, also increased in patients with stage II (P<0.05) and N1 group (P<0.05) compared to those with stage I and free nodes, respectively. In addition, the expression of CD95 on TCM increased in patients with moderately-differentiated tumor cells (grade-II) comparing with those with well-differentiated ones (grade-I, P=0.019). Conclusion: Our data collectively indicates that the frequency as well as mean expression of CD95 on CD8+ central memory subset increases with tumor progression, may be due to chronic exposure with tumor antigens.

Keywords:

Breast cancer , Lymph node , Central Memory CD8+T cells