Expanded effector memory T-lymphocytes in DBA/2 mice do not inhibit the growth of SL2 tumours.

BACKGROUND The aim of this study was to analyse changes in levels of memory T-lymphocytes during growth of SL2 tumours in DBA/2 mice and to evaluate whether these lymphocytes may have an inhibitory effect on tumour growth. MATERIALS AND METHODS Percentages of naïve (CD8+CD44lowCD62L+), central memory (CD8+CD44high CD62L+) and effector memory (CD8+CD44highCD62L-) lymphocytes in the CD8+ subset in peripheral blood, spleen and lymph nodes of tumour-bearing and control mice were analysed by flow cytometry. RESULTS The percentage of effector memory lymphocytes in the CD8+ subset increased during growth of tumours, whereas that of naïve CD8+ lymphocytes decreased. No correlation between the levels of effector memory lymphocytes in peripheral blood and the mass of tumours was found. CONCLUSION SL2 tumours induce expansion of effector memory lymphocytes in DBA/2 mice. However, expanded effector memory lymphocytes do not inhibit the growth of tumours.