The antitumor effect and mechanism of PD-1 antibody.

LIAN Yang-yang; WEI Jie; LIANG Hong; YANG Li- hua

doi:10.3969/j.issn.1001-9448.2017.02.006

Abstract：Objective To investigate the anti -tumor effect and the influence on antitumor immunity of PD -1 an-tibody-indduced PD-L1/PD-1 blockage .Methods Tumor bearing model was established by TC -1 cell injection on C57BL/6 mice.The subjects were randomly assigned into 3 groups (n=3), the negative control group, positive control group and PD-1 antibody group .The anti-tumor effect of PD-1 antibody was assessed using tumor growth curves .The mice were executed when it died or the tumor diameter reached to 2 cm, and the spleens were harvested .The number of splenic mononuclear lymphocytes CD 4 +CD25 +T regulate cells were analyzed by flow cytometry , as the CD8 +T cells in tumor tissues were detected by immunohistochemical method .Results The anti-tumor effects in PD -1 antibody and positive control groups were both significantly higher than that in negative control group (P<0.05), though there was no significant difference between the 2 groups ( P >0.05 ) .The Treg cell ratio to splenic mononuclear lymphocytes were (87.00 ±6.06)% in negative control group, (71.50 ±4.04)% in positive control group and (69.75 ±3.77)% in PD-1 antibody group .They were significantly lower in positive control group and PD -1 antibody group than that in neg-ative control group (P<0.05), though there was no significant difference between the 2 groups (P>0.05).The CD8 +T cell counts in tumor tissues were 2.25 ×1011 ±3.34 ×1010 in negative control group , 1.99 ×1011 ±3.12 ×1010 in posi-tive control group and 3.27 ×1011 ±3.67 ×1010 in PD-1 antibody group.The CD8 +T cell count in PD -1 antibody group was significantly higher than those in the other two groups ( P<0.05 ) .Conclusion PD-1 antibody can inhibit the growth of tumor in mice effectively through the blocking of PD -L1/PD-1 pathway , which may be via the decrease of immunosuppressive cells , and the increase of the CD8 +T cells.