Evaluation of antibody-dependent cell-mediatedcy totoxicity activity and cetuximab response in KRAS wildtype metastatic colorectal cancer patients

AIM:To investigate the prognostic role of invariant natural killer T(iNKT) cells and antibody-dependent cell-mediated cytotoxicity(ADCC) in wild type KRAS metastatic colorectal cancer(mC RC) patients treated with cetuximab.METHODS: Forty-one KRAS wt mC RC patients,treated with cetuximab and irinotecan-based chemotherapy in Ⅱ and Ⅲ lines were analyzed. Genotyping of single nucleotide polymorphism(SNP)s in the FCGR2A,FCGR3A and in the 3' untranslated regions of KRAS and mutational analysis for KRAS,BRAF and NRAS genes was determined either by sequencing or allelic discrimination assays. Enriched NK cells were obtained from lymphoprepperipheral blood mononuclear cell and iN KT cells were defined by co-expression of CD3,TCRVα24,TCRVβ11. ADCC was evaluated as ex vivo NK-dependent activity,measuring lactate dehydrogenase release.RESULTS: At basal,mCRC patients performing ADCC activity above the median level(71%) showed an improved overall survival(OS) compared to patients with ADCC below(median 16 vs 8 mo;P=0.026). We did not find any significant correlation of iN KT cells with OS(P=0.19),albeit we observed a trend to a longer survival after 10 mo in patients with iN KT above median basal level(0.382 cells/microliter). Correlation of OS and progression-free survival(PFS) with interesting SNPs involved in ADCC ability revealed not to be significant. Patients carrying alleles both with A in FCGR2 A and TT in FCGR3A presented a trend of longer PFS(median 9 vs 5 mo;P=0.064). Chemotherapy impacted both iN KT cells and ADCC activity. Their prognostic values get lost when we analysed them after 2 and 4 mo of treatment.CONCLUSION: Our results suggest a link between iN KT cells,basal ADCC activity,genotypes in FCGR2A and FCGR3A,and efficacy of cetuximab in KRAS wt mC RC patients.

Anti-PD-L1 antibody enhances curative effect of cryoablation via antibody-dependent cell-mediated cytotoxicity mediating PD-L1^(high)CD11b^(+)cells elimination in hepatocellular carcinoma

Cryoablation(CRA)and microwave ablation(MWA)are two main local treatments for hepatocellular carcinoma(HCC).However,which one is more curative and suitable for combining with immunotherapy is still controversial.Herein,CRA induced higher tumoral PD-L1 expression and more T cells infiltration,but less PD-L1^(high)CD11b^(+)myeloid cells infiltration than MWA in HCC.Furthermore,CRA had better curative effect than MWA for anti-PD-L1 combination therapy in mouse models.Mechanistically,anti-PD-L1 antibody facilitated infiltration of CD8^(+)T cells by enhancing the secretion of CXCL9 from cDC1 cells after CRA therapy.On the other hand,anti-PD-L1 antibody promoted the infiltration of NK cells to eliminate PD-L1^(high)CD11b^(+)myeloid cells by antibody-dependent cell-mediated cytotoxicity(ADCC)effect after CRA therapy.Both aspects relieved the immunosuppressive microenvironment after CRA therapy.Notably,the wild-type PD-L1 Avelumab(Bavencio),compared to the mutant PD-L1 atezolizumab(Tecentriq),was better at inducing the ADCC effect to target PD-L1^(high)CD11b^(+)myeloid cells.Collectively,our study uncovered the novel insights that CRA showed superior curative effect than MWA in combining with anti-PD-L1 antibody by strengthening CTL/NK cell immune responses,which provided a strong rationale for combining CRA and PD-L1 blockade in the clinical treatment for HCC.

Potential of Antibody-Dependent Cellular Cytotoxicity in Acute and Recovery Phases of SARS-CoV-2 Infection

Background:Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)has caused a global pandemic that has resulted in millions of casualties.Although researchers have reported the existence of neutralizing antibodies and viral T cell immunity against SARS-CoV-2,little is known about the presence of antibody-dependent cellular cytotoxicity(ADCC)and its role in combating SARS-CoV-2 infection.Methods:Nineteen acute COVID-19 patients at the First Affiliated Hospital of Guangzhou Medical University from January to February,2020 and 55 recovery COVID-19 patients at the Second Peoples Hospital of Changde City from February,2020 to February,2021 were recruited in this study.Longitudinal plasma samples were collected.A virus-specific ADCC assay was performed to study the COVID-19 plasma samples.The correlations between ADCC and total IgG titer,including anti-RBD,anti-N,and neutralizing antibody titer were analyzed.Results:A high level of ADCC with 0.86%of IFN-g+CD107a+NK cells induced by anti RBD antibodies and with 0.54%of IFN-g+CD107a+NK cells induced by anti N antibodies was observed.This activity peaked at 3 weeks after disease onset with 1.16%and 0.63%of IFN-g+CD107a+NK cells induced by anti RBD and anti N antibodies respectively,declined to 0.32%and 0.32%of IFN-g+CD107a+NK cells respectively after more than 2 months,and persisted for 12 months after disease onset.The ADCC did not aggravate the severity of COVID-19 in terms of sequential organ failure assessment,although ADCC decreased with the age of COVID-19 patients.Interestingly,ADCC response is not correlated with neutralizing antibody titer or total IgG titers against S protein RBD and N protein in acute patients.ADCC in recovered patients showed a significant correlation with anti RBD IgG titer(R2=0.33,P<0.001).Conclusion:Antibodies from COVID-19 patients against the N protein and S protein RBD domains could stimulate high levels of ADCC response.Our results provide evidence that vaccination should not only focus on neutralizing antibodies but also binding antibodies that may facilitate the antiviral function of ADCC,especially in the elderly.

Current perspectives on dengue episode in Malaysia

To Prevalence of dengue transmission has been alarmed by an estimate of 390 million infections per annum.Urban encroachment,ecological disruption and poor sanitation are all contributory factors of increased epidemiology.Complication however arises from the fact that dengue virus inherently exists as four different serotypes.Secondary infection is often manifested in the more severe form,such that antibody-dependent enhancement(ADE) could aggravate ailment by allowing pre-existing antibodies to form complexes with infecting viruses as means of intrusion.Consequently,increased viraemic litter and suppression of antiviral response are observed.Deep concerns are thus expressed in regards to escalating trend of hospitalisation and mortality rates.In Malaysia,situation is exacerbated by improper clinical management and pending vector control operations.As a preparedness strategy against the potential deadly dengue pandemic,the call for development of a durable and costeffective dengue vaccine against all infecting serotypes is intensified.Even though several vaccine candidates are currently being evaluated in clinical trials,uncertainties in regards to serotypes interference,incomplete protection and dose adequacy have been raised.Instead of sole reliance on outsourcing,production of local vaccine should be considered in coherent to government's efforts to combat against dengue.

The Effect of Tremella Fuciformis Spores Polysaccharides (TSP) on Immune Cellular Function of Mice in Vitro

TSP could markedly enhance the proliferative response of the murine splenocyte to LPS and induce the mitogenesis of the spleen cells.Furthermore,it was able to augment the activity of natural killer cell and ADGG;at a dosage of 25-250μg/ml,the ability of splenocytes to produce IL-2 induced by onA had been improved; at the concentration of 250μg／ml or more,TSP could inhibit the proliferative response of the murine lymphocyte to GonA and the ~3-HTdR spontaneous incorporation rate of thymocytes,and the inhibitory action ran in paralell with the increase in concentration of TSP.

Dynamics of host immune responses to SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2),the most recent global health threat,is spreading throughout the world with worrisome speed,and the current wave of coronavirus disease 2019(COVID-19)seems to have no mercy.While this mysterious virus challenges our ability to control viral infections,our opportunities to control the COVID-19 pandemic are gradually fading.Currently,pandemic management relies on preventive interventions.Although prevention is a good strategy to mitigate SARS-CoV-2 transmission,it still cannot be considered an absolute solution to eliminate this pandemic.Currently,developing a potent immunity against this viral infection seems to be the most promising strategy to drive down this ongoing global tragedy.However,with the emergence of new challenges in the context of immune responses to COVID-19,the road to control this devastating pandemic seems bumpier;thus,it is pivotal to characterize the dynamics of host immune responses to COVID-19,in order to develop efficient prophylactic and therapeutic tools.This begs the question of whether the effector mechanisms of the immune system are indeed potent or a possible contributing factor to developing more severe and lethal forms of COVID-19.In this review,the possible role of the immunopathologic phenomena including antibody-dependent enhancement,cytokine storm,and original antigenic sin in severity and mortality of COVID-19 will be discussed.

Electrophoretic Analysis on RNA of Deltamethrin－resistant Culex Pipiens Pallens

TSP could markedly enhance the proliferative response of the murine splenocyte to LPS and induce the mitogenesis of the spleen cells.Furthermore,it was able to augment the activity of natural killer cell and ADGG;at a dosage of 25-250μg/ml,the ability of splenocytes to produce IL-2 induced by onA had been improved; at the concentration of 250μg/ml or more,TSP could inhibit the proliferative response of the murine lymphocyte to GonA and the ￣3-HTdR spontaneous incorporation rate of thymocytes,and the inhibitory action ran in paralell with the increase in concentration of TSP.

Novel Strategies for Redirecting NK Cells in Cancer Immunotherapy

Natural killer(NK)cells act as a first line of defense in innate immune system against new malignant transformed cells without prior exposure to tumor antigens.The activity of NK cells is tightly controlled by a balance between inhibitory receptors and activating receptors,and when activation signals outweigh inhibitory signals,NK cells can mediate a response to eliminate the targeted cells.As a bridge between the innate and adaptive immune responses to enhance destruction of tumors,NK cells kill their tumor targets through a variety of mechanisms,including receptor-mediated cytotoxicity,antibody-dependent cell-mediated cytotoxicity(ADCC),death receptor Fas/FasL signaling pathway-mediated cancer apoptosis.However,the efficacy of using NK cells for tumor immunotherapy has been limited by a lack of antigen specificity.To overcome this limitation,Vallera and colleagues developed a bispecific killer cell engager(BiKE),which is comprised of a first ScFv that recognizes a tumor antigen and a second ScFv against CD16(expressed on NK cells)to trigger ADCC.To overcome the poor expansion of NK cells in vivo,a novel trispecific killer cell engager(TriKE)was evolved from the BiKE by the same team.In this molecule,IL-15 was integrated to promote NK cell expansion,thereby eliciting superior NK cytotoxicity and NK cell persistence in vivo compared to BiKE.In order to simultaneously target drug-refractory cancer stem cells(CSC)and cancer cells,a novel tetraspecific killer engager(TetraKE)comprising anti-CD133,EpCAM,CD16 ScFvs and a sustaining IL-15 signal cross-linker was recently developed.Compared to BiKE or TriKE,TetraKE1615EpCAM133 was highly specific against EpCAM-and CD133-bearing cells,leading to enhanced NK cell proliferation,prolonged survival and a limited cytokine response.This TetraKE represents a promising new modality for immunotherapy.

IgG Fc engineering to modulate antiboc affector functions

Therapeutic monoclonal antibodies are among the most effective biotherapeutics to date. An important aspect of antibodies is their ability to bind antigen while at the same time recruit immune effector functions. The majority of approved recombinant monoclonal antibody therapies are of the human IgG1 subclass, which can engage both humoral and cellular components of the immune system. The wealth of information generated about antibodies has afforded investigators the ability to molecularly engineer antibodies to modulate effector functions. Here, we review various antibody engineering efforts intended to improve efficacy and safety relative to the human IgG isotype. Further, we will discuss pro- posed mechanisms by which engineering approaches led to modified interactions with immune components and provide examples of clinical studies using next generation antibodies.

Understanding SARS-CoV-2-Mediated Inflammatory Responses: From Mechanisms to Potential Therapeutic Tools

Currently there is no effective antiviral therapy for SARS-CoV-2 infection, which frequently leads to fatal inflammatory responses and acute lung injury. Here, we discuss the various mechanisms of SARS-CoV-mediated inflammation. We also assume that SARS-CoV-2 likely shares similar inflammatory responses. Potential therapeutic tools to reduce SARS-CoV-2-induced inflammatory responses include various methods to block FcR activation. In the absence of a proven clinical FcR blocker, the use of intravenous immunoglobulin to block FcR activation may be a viable option for the urgent treatment of pulmonary inflammation to prevent severe lung injury. Such treatment may also be combined with systemic anti-inflammatory drugs or corticosteroids. However, these strategies, as proposed here, remain to be clinically tested for effectiveness.

Immune mechanism and clinical significance of macrophage to medullary hematopoietic injury of immune-related hematocytopenia patients

Background Immune-related hematocytopenia （IRH） is considered to be related with the production of autoantibody, as well as the activation of humoral immunity which is stimulated by B lymphocyte. This study aimed to observe the levels of various cytokines in the blood serum and the in situ active state of macrophage （Me） in the medullary hematopoietic microenvironment of IRH patients, and to probe into the immune mechanism and clinical significance of Me in hematopoietic cell injury. Methods ELISA is used to detect the IL-4, IL-6, IL-12, IL-17, and IFN-y levels in the peripheral blood serum of 376 patients in pre- and post-therapy. Cytochemistry and cell immunochemistry methods are used to observe the peroxidase （POX）, nonspecific esterase （NSE）, hemosiderin granules, and HLA-DR activity of Me in the bone marrow of patients. Immunofluorescence is used to observe the expression of hemocyte antihuman globulin IgG antibody, lymphocytes CD4 molecule, Me membrane Fcyllreceptor （FcyllR）, mannitose receptor （MR）, IFN-y, ICAM-1, IL-12, and IL-17A and the formation mechanism of antibody-dependent cell-mediated cytotoxicity （ADCC） hematopoietic cell islands （HI） in the medullary hematopoietic microenvironment of patients. Glucocorticoid is used for treatment on the basis of anti-infection therapy, and gamma globulin stoss therapy is used for the appearance of ADCC-type HI or serious Me bloodthirsty phenomenon; if necessary, association of Cyclosporine A （CsA） should be used and chalybeate should be supplemented. Results In the patient group, the levels of IL-4, IL-6, IL-12, IL-17, and IFN-y were increased. After treatment, the cytokine levels gradually became normal. The activated Me in the marrow highly expressed NSE and POX, and Me swallowed more hemosiderin particles, but the iron in the cytoplasm of immature erythrocytes decreased. The activated Me expressed HLA-DR, MR, ICAM-1, IFN-y, and IL-12. For patients with humoral immunity activation and bacterial infection, Me weakly expressed IL-17A but highly expressed FcyIIR, and the phenomenon that ADCC-type HI broke pathological blood corpuscles often occurred; for the cellular immune activation along with virus infection, the white blood count （WBC） significantly reduced, Me weakly expressed FcyIIR, secretory highly expressed IL-17A, and the phenomena that Me adhered to, captured and swallowed blood cell often occurred. After four weeks of anti-infective and immunosuppressive therapy, nuclear apoptosis of Me occurred in the bone marrow of patients, HI and bloodthirsty phenomenon disappeared, and the peripheral blood picture started to improve. Conclusions Me is an important antigen presenting cell in the IRH marrow for hematopoiesis destruction and an immune effector cell of hematopoietic injury; infection can promote the activation of Me, upregulate the impression of immune molecule and receptors, form ADCC HI. aeGravate hematoBoietic iniurv, and accelerate the destruction on hematoDoietic cell.

Promotion of cell proliferation and inhibition of ADCC by cancerous immunoglobulin expressed in cancer cell lines

To explore the significance of cancerous immunoglobulin(Ig)in cancer cell growth,HeLa cervical cancer cells were stably transfected with small interfering RNA(siRNA)that specifically,efficiently and consistently silences the expression of heavy chain genes of all immunoglobulin isotypes.This stable cell line was used to examine cell viability,colony formation and tumor growth in athymic nude mice.The results of these experiments indicated that siRNA-mediated knockdown of cancerous Ig inhibited cell growth in vitro and suppressed tumor cell growth in immune-deficient nude mice in vivo.Similarly,this siRNA also inhibited the growth of MGC gastric cancer cells and MCF-7 breast cancer cells.Furthermore,the presence of cancerous Ig specifically reduced antibody-dependent cell-mediated cytotoxicity(ADCC)induced by an anti-human epithelial growth factor receptor(EGFR)antibody in a dose-dependent manner,suggesting that the cancerous Ig-Fc receptor interaction inhibits natural killer cell(or NK cell)effector function.The prevalent expression of Ig in human carcinomas and its capacity to promote growth and inhibit immunity might have important implications in growth regulation and targeted therapy for human cancers.

An ultrapotent pan-β-coronavirus lineage B(β-CoV-B)neutralizing antibody locks the receptor-binding domain in closed conformation by targeting its conserved epitope

New threats posed by the emerging circulating variants of SARS-CoV-2 highlight the need to find conserved neutralizing epitopes for therapeutic antibodies and efficient vaccine design.Here,we identified a receptorbinding domain(RBD)-binding antibody,XG014,which potently neutralizesβ-coronavirus lineage B(β-CoV-B),including SARS-CoV-2,its circulating variants,SARSCoV and bat SARSr-CoV WIV1.Interestingly,antibody family members competing with XG014 binding show reduced levels of cross-reactivity and induce antibodydependent SARS-CoV-2 spike(S)protein-mediated cellcell fusion,suggesting a unique mode of recognition by XG014.Structural analyses reveal that XG014 recognizes a conserved epitope outside the ACE2 binding site and completely locks RBD in the non-functional“down”conformation,while its family member XG005 directly competes with ACE2 binding and position the RBD“up”.Single administration of XG014 is effective in protection against and therapy of SARS-CoV-2 infection in vivo.Our findings suggest the potential to develop XG014 as pan-β-CoV-B therapeutics and the importance of the XG014 conserved antigenic epitope for designing broadly protective vaccines againstβ-CoV-B and newly emerging SARS-CoV-2 variants of concern.

Monoclonal antibody pharmacogenomics in cancer treatment

Conventionally, in the pharmacokinetic/pharmacodynamic analysis of small molecule compounds such as cytotoxic anticancer drugs, polymorphism analysis of genes related to absorption, distribution, metabolism, and excretion has been performed in addition to the analyses of blood concentrations of drugs. Such pharmacogenetic factors play an important role in predicting therapeutic effects and adverse events and in the proper use of drugs. With the recent launch of immune checkpoint inhibitors (ICIs) and the rapid development of antibody-drug conjugates (ADCs) currently underway, there is no doubt that antibody drugs, which are large molecule compounds, will become key drugs in anticancer drug treatment. However, the pharmacokinetic and pharmacodynamic analysis of antibody drugs is still not sufficient, and further elucidation of factors and mechanisms affecting their dynamics in the human body is necessary. Moreover, the pharmacogenomic factors of antibody drugs have not yet been fully studied. There are many factors that should be clarified, such as factors that regulate the host immune response in ICI therapy and the effects of ATP-binding cassette transporter and cytochrome P450 on the payload of ADCs. This review provides an outline of antibody drugs in cancer treatment and summarizes the pharmacogenomic factors of antibody drugs known to date.