Enhancement of anti-CD4 mAb on anti-tumor activity of tumor-specific T cells activated by rIL-2 and anti-CD3 mAb

Aim To explore enhancing effects of anti CD4 mAb on the proliferation and anti tumor activity of tumor specific T cells stimulated by anti CD3 mAb. Methods Four different procedures were applied to culture splenocytes from tumor cell immunized mice:(1)cultured in 2×104U/L rIL 2 alone(IL 2 group);(2) cultured in anti CD3 mAb alone (anti CD3 group); (3) activated by anti CD3 mAb for 48 h and then cultured in anti CD3 mAb plus 2×104U/L rIL 2 (anti CD3+IL 2 group); (4) activated by anti CD3 and anti CD4 mAbs for 48 h and then cultured in anti CD3 and anti CD4 mAbs plus 2×104U/L rIL 2(anti CD3+IL 2+anti CD4 group). Effects of anti CD4 mAb on proliferation, anti tumor activity and phenotype of tumor specific T cells were studied by 3H TdR incorporation, 3H TdR realease assay and FACS respectvely. Results 3H TdR incorporation(cpm) in the cultured splenocytes from anti CD3+IL 2+anti CD4 group were 46 193, 31 047 and 7 443 on day 6, 12 and 20 respectively, while 3H TdR incorporation(cpm) in the cultured splenocytes from anti CD3+IL 2 group were 22 045, 13 986 and 1 931 on day 6,12 and 20 respectively. The maximum anti tumor activities of both group cells were 83.6% and 91.7% respectively on day 12. The cell phenotype analysis by FACS on day 12 indicated that phenotype of more than 99% effective cells in anti CD3+IL 2+anti CD4 group were Thy1.2+. The percentage of CD4+ and CD25+ T cells in anti CD3+IL 2+anti CD4 group was also higher than that in anti CD3+IL 2 group. Conclusion Anti CD4 mAb may enhance the proliferation and anti tumor activity of tumor specific T cells activated by rIL 2 and anti CD3 mAb.