Influence of FcγRIIIa polymorphism on rituximab-dependent NK cell-mediated cytotoxicity to Raji cells / 中国实验血液学杂志

Fcgamma receptor IIIa (FcγRIIIa) polymorphisms is considered to influence clinical response to therapeutic monoclonal antibody (McAb) in cancer, most people believe it can affect McAb binding, and McAb-dependent NK cell-mediated cytotoxicity. This study was purposed to determine the difference of antibody-dependent cell-mediated cytotoxicity (ADCC) effects mediated by different FcγRIIIa NK cells. The FcγRIIIa genotypes were detected by nest-PCR, the target cells (Raji cells) were stained with 5- (and 6-) carboxyfluorescein diacetate succinimidyl ester (CFSE), cultured with effector cells with different FcγRIIIa genotypes, and finally stained with propidium iodide (PI); the CD20 expression of Raji cells were tested by flow cytometry and cytotoxic index was calculated as well. The results indicated that the ADCC cytotoxic indexes of NK cells with FcγRIIIa-158V/V and FcγRIIIa-158V/F were 69.05±2.38% and 39.63±3.86% respectively, as compared with NK cells with FcγRIIIa158 V/V, ADCC effect of NK cells with FcγRIIIa-158 on Raji cells was obviously weakened with significant difference (p<0.05). It is concluded that FcγRIIIa polymorphism can influence ADCC activity of NK cells, ADCC activity of NK cells with FcγRIIIa-158V/V is higher than that of NK cells with FcγRIIIa-158V/F.

Progress of study on antitumor effects of antibody dependent cell mediated cytotoxicity--review / 中国实验血液学杂志

In recent years, as increasing of monoclonal antibody application in clinic, the antitumor effect of antibody dependent cell-mediated cytotoxicity (ADCC) get increasing attention. The natural killer (NK) cells are the most important effector cells mediating specific antitumor of ADCC; the phagocytes, T-cells and granulocytes have the definite effect on antitumor of ADCC. ADCC is confirmed as the important mechanism and means for clinically treating the cancers with monoclonal antibodies. The IgG antibody firstly combines with target cells (tumor cells) through antigen-binding sites, and then FcγR on effector cells identifies its Fc fragment and mediates ADCC. Today many kinds of monoclonal antibodies have been put into clinical application such as rituximab and other new anti-CD20 monoclonal antibodies including trastuzumab, erbitux, cetuximab, edrecolomab, nimotuzumab, gemtuzumab ozogamicin and so on, which all can mediate ADCC. The antitumor effects of ADCC mediated by monoclonal antibody can be influenced by IgG Fc receptor gene polymorphism, tumor cell antigen, serum antibody levels, cytokines and drugs etc. As to peripheral blood mononuclear cells, ADCC efficacies of FcγRIIIa-158V/V and FcγRIIa-131H/H are higher than that of other genotypes, while increasing the level of tumor antigen and decreasing the level of serum antibody or adding some cytokines (IL-2, IL-21, IL-15, etc) may elevate the ADCC effect mediated by monoclonal antibodies. Avoiding use of certain drugs (dexamethasone, TNF antagonist) or appropriately using of ondansetron and clemastine also can enhance the anti-tumor effect of ADCC mediated by monoclonal antibodies. In short, ADCC is very important in clinical application for anti-tumor treatment, but its efficacy may be impacted by multiple factors.In this article, the killing mechanisms of ADCC, the clinical use of monoclonal antibodies with antitumor effect of ADCC, the factors influencing anti-tumor efficacy of ADCC, and the antitumor effects of ADCC by other cells are reviewed.

Fcγ receptorIIIa polymorphism in healthy children and those with hematological malignancies / 中国实验血液学杂志

Fcγ receptorIIIa (FcγRIIIa) polymorphism was considered to influence clinical response to therapeutic monoclonal antibody (MAb) against cancer, which is suggested to affect MAb binding and MAb-dependent NK cell-mediated cytotoxicity. The purpose of this study was to examine the FcγRIIIa gene polymorphisms in healthy children and in children with hematological malignancy, and to explore its possible effect on MAb in children with hematological malignancies. 43 healthy children (H) and 20 pediatric patients with hematological malignancies (HM) were enrolled in this study. DNA was isolated from peripheral blood, and then nest-polymerase chain reaction-restriction fragment length polymorphism (nest-PCR and PCR-RFLP) was used to determine the FcγRIIIa-158 genotypes in each groups of subject, digested fragments were subjected to electrophoresis on 15% PAGE. The results showed that there were a higher frequencies of FcγRIIIa-158V/F in H and HM group (72.1% and 75.0% respectively), the frequencies of FcγRIIIa-158V/V were 27.9% and 25.0% in H and HM group respectively, but there was no FcγRIIIa-158F/F in the two groups. No significant difference in distribution of the FcγRIIIa-158 genotype was found between HM and H groups (p > 0.05). It is concluded that FcγRIIIa-158V/F is more frequent, while FcγRIIIa-158V/V is less, but FcγRIIIa-158F/F is very rare in both groups. No significant difference of FcγRIIIa polymorphism distribution is found between healthy and hematological malignancy groups.