Vaccine-induced systemic and mucosal T cell immunity to SARS-CoV-2 viral variants

The first-generation COVID-19 vaccines have been effective in mitigating severe illness and hospitalization, but recurring waves of infections are associated with the emergence of SARS-CoV-2 variants that display progressive abilities to evade antibodies, leading to diminished vaccine effectiveness. The lack of clarity on the extent to which vaccine-elicited mucosal or systemic memory T cells protect against such antibody-evasive SARS-CoV-2 variants remains a critical knowledge gap in our quest for broadly protective vaccines. Using adjuvanted spike protein–based vaccines that elicit potent T cell responses, we assessed whether systemic or lung-resident CD4 and CD8 T cells protected against SARS-CoV-2 variants in the presence or absence of virus-neutralizing antibodies. We found that 1) mucosal or parenteral immunization led to effective viral control and protected against lung pathology with or without neutralizing antibodies, 2) protection afforded by mucosal memory CD8 T cells was largely redundant in the presence of antibodies that effectively neutralized the challenge virus, and 3) “unhelped” mucosal memory CD8 T cells provided no protection against the homologous SARS-CoV-2 without CD4 T cells and neutralizing antibodies. Significantly, however, in the absence of detectable virus-neutralizing antibodies, systemic or lung-resident memory CD4 and “helped” CD8 T cells provided effective protection against the relatively antibody-resistant B1.351 (β) variant, without lung immunopathology. Thus, induction of systemic and mucosal memory T cells directed against conserved epitopes might be an effective strategy to protect against SARS-CoV-2 variants that evade neutralizing antibodies. Mechanistic insights from this work have significant implications in the development of T cell–targeted immunomodulation or broadly protective SARS-CoV-2 vaccines.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has continued to exert devastating impacts on the human life, with >280 million infections and over 5.4 million deaths to date. Although there are millions of convalescent people with some measure of immunity and 8.8 billion doses of vaccine administered to date, further threats of widespread severe COVID-19 disease looms heavily as immunity induced by infection or the first-generation vaccines may not provide effective and durable protection, either due to waning immunity or due to poor antibody cross-reactivity to new variants (1–5).It is clear that virus-neutralizing antibodies provide the most effective protection to SARS-CoV-2, following vaccination or recovery from infection (6). However, T cell–based protection against SARS-CoV-2 has become a central focus because T cells recognize short amino acid sequences that can be conserved across viral variants (7–9). Indeed, T cells in convalescent COVID-19 patients have shown robust responses that are directed at multiple viral proteins, and depletion of these T cells delayed SARS-CoV-2 control in mice (10–12). These data suggest a protective role for T cells in COVID-19 infection. In effect, what constitutes an effective, an ineffective, or a perilous T cell response to SARS-CoV-2 in lungs remains poorly defined. Controlled studies in laboratory animals are of critical importance to elucidate the role and nature of T cells in lungs during SARS-CoV-2 virus infection and in protective immunity.Based on the differentiation state, anatomical localization and traffic patterns, memory T cells are classified into effector memory (T_EM), central memory (T_CM), and tissue-resident memory (T_RM) (13, 14). There is accumulating evidence that airway/lung-resident T_RMs, and not migratory memory T cells (T_EMs) are critical for protective immunity to respiratory mucosal infections with viruses, such as influenza A virus (IAV) and respiratory syncytial virus (15–21). Development of T_RMs from effector T cells in the respiratory tract requires local antigen recognition and exposure to critical factors, such as transforming growth factor (TGF)-β and interleukin (IL)-15 (15). Therefore, mucosal vaccines are more likely to elicit T_RMs in lungs than parenteral vaccines (22, 23). A subset of effector T cells in airways of COVID-19 patients display T_RM-like features (24), but the development of T_RMs or their importance in protective immunity to reinfection are yet to be determined. Furthermore, all SARS-CoV-2 vaccines in use are administered parenterally and less likely to induce lung T_RMs. While depletion of CD8 T cells compromised protection against COVID-19 in vaccinated rhesus macaques (25), the relative effectiveness of vaccine-induced systemic/migratory CD8 T cell memory vs. lung/airway T_RMs in protective immunity to COVID-19 is yet to be defined.In this study, using the K18-hACE2 transgenic (tg) mouse model of SARS-CoV-2 infection, we have interrogated two key aspects of T cell immunity: 1) the requirements for lung-resident vs. migratory T cell memory in vaccine-induced immunity to SARS-CoV-2; and 2) the role of lung-resident memory CD4 vs. CD8 T cells in protection against viral variants in the presence or absence of virus-neutralizing antibodies. Studies of mucosal versus systemic T cell–based vaccine immunity using a subunit protein-based adjuvant system that elicits neutralizing antibodies and T cell immunity, demonstrated that: 1) both mucosal and parenteral vaccinations provide effective immunity to SARS-CoV-2 variants; 2) CD4 T cell–dependent immune mechanisms exert primacy in protection against homologous SARS-CoV-2 strain; and 3) the development of spike (S) protein-specific “unhelped” memory CD8 T cells in the respiratory mucosa are insufficient to protect against a lethal challenge with the homologous Washington (WA) strain of SARS-CoV-2. Unexpectedly, we found that systemic or mucosal lung-resident memory CD4 and “helped” CD8 T cells engendered effective immunity to the South African B1.351 β-variant in the apparent absence of detectable mucosal or circulating virus-neutralizing antibodies. Taken together, mechanistic insights from this study have advanced our understanding of viral pathogenesis and might drive rational development of next-generation broadly protective SARS-CoV-2 vaccines that induce humoral and T cell memory.     

Impact of natural selection on global patterns of genetic variation and association with clinical phenotypes at genes involved in SARS-CoV-2 infection

Human genomic diversity has been shaped by both ancient and ongoing challenges from viruses. The current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has had a devastating impact on population health. However, genetic diversity and evolutionary forces impacting host genes related to SARS-CoV-2 infection are not well understood. We investigated global patterns of genetic variation and signatures of natural selection at host genes relevant to SARS-CoV-2 infection (angiotensin converting enzyme 2 [ACE2], transmembrane protease serine 2 [TMPRSS2], dipeptidyl peptidase 4 [DPP4], and lymphocyte antigen 6 complex locus E [LY6E]). We analyzed data from 2,012 ethnically diverse Africans and 15,977 individuals of European and African ancestry with electronic health records and integrated with global data from the 1000 Genomes Project. At ACE2, we identified 41 nonsynonymous variants that were rare in most populations, several of which impact protein function. However, three nonsynonymous variants (rs138390800, rs147311723, and rs145437639) were common among central African hunter-gatherers from Cameroon (minor allele frequency 0.083 to 0.164) and are on haplotypes that exhibit signatures of positive selection. We identify signatures of selection impacting variation at regulatory regions influencing ACE2 expression in multiple African populations. At TMPRSS2, we identified 13 amino acid changes that are adaptive and specific to the human lineage compared with the chimpanzee genome. Genetic variants that are targets of natural selection are associated with clinical phenotypes common in patients with COVID-19. Our study provides insights into global variation at host genes related to SARS-CoV-2 infection, which have been shaped by natural selection in some populations, possibly due to prior viral infections.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Coronaviruses are enveloped, positive-sense, and single-stranded RNA viruses, many of which are zoonotic pathogens that crossed over into humans. Seven coronavirus species, including SARS-CoV-2, have been discovered that, depending on the virus and host physiological condition, may cause mild or lethal respiratory disease. There is considerable variation in disease prevalence and severity across populations and communities. Importantly, minority populations in the United States appear to have been disproportionally affected by COVID-19 (1, 2). For example, in Chicago, more than 50% of COVID-19 cases and nearly 70% of COVID-19 deaths are in African Americans (who make up 30% of the population of Chicago) (1). While social and economic factors are largely responsible for driving COVID-19 health disparities, investigating genetic diversity at host genes related to SARS-CoV-2 infection could help identify functionally important variation, which may play a role in individual risk for severe COVID-19 infection.In this study, we focused on four key genes playing a role in SARS-CoV-2 infection (3). The ACE2 gene, encoding the angiotensin-converting enzyme-2 protein, was reported to be a main binding site for severe acute respiratory syndrome coronavirus (SARS-CoV) during an outbreak in 2003, and evidence showed stronger binding affinity to SARS-CoV-2, which enters the target cells via ACE2 receptors (3, 4). The ACE2 gene is located on the X chromosome (chrX); its expression level varies among populations (5); and it is ubiquitously expressed in the lung, blood vessels, gut, kidney, testis, and brain, all organs that appear to be affected as part of the COVID-19 clinical spectrum (6). SARS-CoV-2 infects cells through a membrane fusion mechanism, which in the case of SARS-CoV, is known to induce down-regulation of ACE2 (7). Such down-regulation has been shown to cause inefficient counteraction of angiotensin II effects, leading to enhanced pulmonary inflammation and intravascular coagulation (7). Additionally, altered expression of ACE2 has been associated with cardiovascular and cerebrovascular disease, which is highly relevant to COVID-19 as several cardiovascular conditions are associated with severe disease. TMPRSS2, located on the outer membrane of host target cells, binds to and cleaves ACE2, resulting in activation of spike proteins on the viral envelope and facilitating membrane fusion and endocytosis (8). Two additional genes, DPP4 and LY6E, have been shown to play an important role in the entry of SARS-CoV-2 virus into host cells. DPP4 is a known functional receptor for the Middle East respiratory syndrome coronavirus (MERS-CoV), causing a severe respiratory illness with high mortality (9, 10). LY6E encodes a glycosylphosphatidylinositol-anchored cell surface protein, which is a critical antiviral immune effector that controls coronavirus infection and pathogenesis (11). Mice lacking LY6E in hematopoietic cells were susceptible to murine coronavirus infection (11).Previous studies of genetic diversity at ACE2 and TMPRSS2 in global human populations did not include an extensive set of African populations (5, 12–14). No common coding variants (defined here as minor allele frequency [MAF] > 0.05) at ACE2 were identified in any prior population studies. However, few studies included diverse indigenous African populations whose genomes harbor the greatest diversity among humans. This leads to a substantial disparity in the representation of African ancestries in human genetic studies of COVID-19, impeding health equity as the transferability of findings based on non-African ancestries to African populations can be low (15). Including more African populations in studying the genetic diversity of genes involved in SARS-CoV-2 infection is extremely necessary. Additionally, the evolutionary forces underlying global patterns of genetic diversity at host genes related to SARS-CoV-2 infection are not well understood. Using methods to detect natural selection signatures at host genes related to viral infections helps identify putatively functional variants that could play a role in disease risk.We characterized genetic variation and studied natural selection signatures at ACE2, TMPRSS2, DPP4, and LY6E in ethnically diverse human populations by analyzing 2,012 genomes from ethnically diverse Africans (referred to as the “African diversity” dataset), 2,504 genomes from the 1000 Genomes Project (1KG), and whole-exome sequencing of 15,977 individuals of European ancestry (EA) and African ancestry from the Penn Medicine BioBank (PMBB) dataset (SI Appendix, Fig. S1). The African diversity dataset includes populations with diverse subsistence patterns (hunter-gatherers, pastoralists, agriculturalists) and speaking languages belonging to the four major language families in Africa (Khoesan; Niger–Congo, of which Bantu is the largest subfamily; Afroasiatic; and Nilo-Saharan). We identify functionally relevant variation, compare the patterns of variation across global populations, and provide insight into the evolutionary forces underlying these patterns of genetic variation. In addition, we perform an association study using the variants identified from whole-exome sequencing at the four genes and clinical traits derived from electronic health record (EHR) data linked to the subjects enrolled in the PMBB. The EHR data include diseases related to organ dysfunctions associated with severe COVID-19, such as respiratory, cardiovascular, liver, and renal complications. Our study of genetic variation in genes involved in SARS-CoV-2 infection provides data to investigate infection susceptibility within and between populations and indicates that variants in these genes may play a role in comorbidities relevant to COVID-19 severity.     

New‐onset pemphigus foliaceus following SARS‐CoV‐2 infection and unmasking multiple sclerosis: A case report

Development of pemphigus foliaceus (PF) following SARS‐CoV‐2 infection has only been reported in one patient who had received Bamlanivimab and thus might be considered as a drug‐induced case of PF. Here, we reported the first case of PF arising solely after COVID infection without taking any culprit drug.     

LncRNA SNHG1 promotes renal cell carcinoma progression through regulation of HMGA2 via sponging miR‐103a

BackgroundLong noncoding RNAs (LncRNAs) plays a vital role in tumorigenesis and development. The molecular mechanism of SNHG1 in renal cell carcinoma (RCC) has not been illustrated. The aim of this research was to explore the expression and function of LncRNA SNHG1 in RCC.Material and MethodsThe expression of SNHG1 in clinical tissues and RCC cell lines was detected. Luciferase reporter assay was performed to verify the correlation between SNHG1, miR‐103a, and HMGA2. CCK‐8 assay was performed to examine cell viability. Cell apoptosis was analyzed using flow cytometry. Cell invasion capacity was determined by Transwell assays. The protein level of HMGA2 was analyzed by Western blotting.ResultsThe expression of SNHG1 markedly increased in RCC tissues and cell lines. Subsequent studies identified SNHG1 as a miRNA sponge for miR‐103a. In addition, SNHG1 knockdown and miR‐103a overexpression significantly inhibited progression of RCC. miR‐103a also regulated HMGA2 levels.ConclusionOur findings showed that SNHG1 was upregulated in RCC cells and tissues. SNHG1 promoted the malignant characteristics of RCC cells. Its regulatory effect may be regulation of HMGA2 by sponging miR‐103a. Therefore, Our study facilitates the understanding of SNHG1 function in RCC.     

SLC2A3 variants in familial and sporadic congenital heart diseases in a Chinese Yunnan population

BackgroundSolute carrier family 2 member 3 (SLC2A3), is a member of a superfamily of transport protein genes. SLC2A3 played an important role in embryonic development. Previous research reported SLC2A3 duplication was reportedly associated with congenital syndromic heart defects. However, it is not clear whether the gene is associated with non‐syndromic congenital heart disease. Our study aimed to elucidate the relationship between its variation and congenital heart disease.MethodsGenomic DNA extracted from the peripheral blood leukocytes of two families with CHD were sequenced with whole‐exome sequencing to identify variations, used Sanger sequencing to investigate SLC2A3 variants in 494 Chinese patients with CHD and 576 healthy unrelated individuals.ResultsIn members from the two families, three with CHD had the SLC2A3 (rs3931701) C > T variant. Of the 494 patients with CHD, 394 had gene variants (86 had the TT type and 308 had the CT type). Of the 576 healthy controls, 272 participants had gene variants (36 had the TT type and 236 had the CT type). The TT type [p < 0.0001, odds ratio (OR) =7.262, 95% confidence interval (CI) =4.631–11.388] and CT type (p < 0.0001, OR =3.967, 95% CI =2.991–5.263) of SLC2A3 (rs3931701) significantly increased the risk of sporadic ASD in a Chinese Yunnan population.ConclusionsSingle nucleotide variations of SLC2A3, particularly, the SLC2A3 (rs3931701) C > T variant increased the risk of CHD among the studied population.     

葛根芩连汤及其加减方改善2型糖尿病胰岛素抵抗作用研究进展

葛根芩连汤出自《伤寒杂病论》,为表里双解治疗协热下利的代表方剂,全方由葛根、黄芩、黄连、炙甘草配伍而成,四药合用可外疏内清,共达清热止利,表里同解之效。现临床上基于异病同治的原则将葛根芩连汤用于2型糖尿病（T2DM）的治疗,取得了良好的疗效。T2DM是一种以血糖水平升高为主要特征的慢性代谢性疾病,其病因和发病机制十分复杂,主要与遗传、生活方式、环境及饮食等因素相关。临床观察及实验研究显示,葛根芩连汤及其药效成分可有效防治T2DM。临床上常将葛根芩连汤加减应用或联合西药应用,其治疗效果明显优于单独使用西药。临床实践证实葛根芩连汤可以有效缓解T2DM患者临床症状,减轻胃肠道等不良反应,并减少并发症的发生。实验研究表明葛根芩连汤可通过调控胰岛传导通路及炎症信号通路、缓解氧化应激反应、调节肠道菌群等方式来增强患者胰岛功能,改善胰岛素抵抗,从而治疗T2DM。但目前关于葛根芩连汤通过改善胰岛素抵抗治疗T2DM的机制尚待进一步研究,故该文就葛根芩连汤改善T2DM胰岛素抵抗的临床及实验基础研究进展进行系统综述,以期为葛根芩连汤治疗T2DM作用机制的后续深入研究及其临床防治提供理论和数据参考。     

基于立体MDT模式引导下2型糖尿病患者临床护理路径的构建与应用

目的 构建基于立体MDT模式引导下2型糖尿病(T2DM)患者临床护理路径,旨在使临床护理工作流程化、路径化.方法 以住院患者需求调查表与患者舒适度调查表为横断面调查工具,对2018年1月～11月在我院内分泌科接受住院治疗的80例T2DM患者的护理需求、满意度及舒适状况进行横断面调查,为基于立体MDT模式引导下T2DM患...     

Sodium Glucose Cotransporter-2 Inhibitors as an Add-on Therapy to Metformin Plus Dipeptidyl Peptidase-4 Inhibitor in Patients with Type 2 Diabetes

PurposeTo date, no study has compared the effects of adding sodium glucose cotransporter-2 (SGLT-2) inhibitors to the combination of metformin plus dipeptidyl peptidase-4 (DPP-4) inhibitors to the effects of adding other conventional anti-diabetic drugs (ADDs) to the dual therapy. We aimed to compare the effect of adding SGLT-2 inhibitors with that of adding sulfonylurea (SU) in type 2 diabetes (T2D) patients inadequately controlled with metformin plus DPP-4 inhibitors.Materials and MethodsThis study was designed to evaluate the non-inferiority of SGLT-2 inhibitor to SU as an add-on therapy to the dual combination of metformin plus DPP-4 inhibitors. A total of 292 T2D patients who started SU or SGLT-2 inhibitors as an add-on therapy to metformin plus DPP-4 inhibitors due to uncontrolled hyperglycemia, defined as glycated hemoglobin (HbA1c) ≥7%, were recruited. After propensity score matching, 90 pairs of patients remained, and 12-week changes in HbA1c levels were reviewed to assess glycemic effectiveness. Data from these patients were analyzed retrospectively.ResultsAfter 12 weeks of triple therapy, both groups showed significant changes in HbA1c levels, with a mean of -0.9% in each group. The inter-group difference was 0.01% [95% confidence interval (CI): -0.26–0.27], and the upper limit of the 95% CI was within the limit for non-inferiority (0.40%). There were no inter-group differences in the changes of liver enzyme levels and kidney function.ConclusionAdding SGLT-2 inhibitors is not inferior to adding SU as a third-line ADD to metformin plus DPP-4 inhibitor combination therapy.     

Dromedary camel nanobodies broadly neutralize SARS-CoV-2 variants

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike is a trimer of S1/S2 heterodimers with three receptor-binding domains (RBDs) at the S1 subunit for human angiotensin-converting enzyme 2 (hACE2). Due to their small size, nanobodies can recognize protein cavities that are not accessible to conventional antibodies. To isolate high-affinity nanobodies, large libraries with great diversity are highly desirable. Dromedary camels (Camelus dromedarius) are natural reservoirs of coronaviruses like Middle East respiratory syndrome CoV (MERS-CoV) that are transmitted to humans. Here, we built large dromedary camel V_HH phage libraries to isolate nanobodies that broadly neutralize SARS-CoV-2 variants. We isolated two V_HH nanobodies, NCI-CoV-7A3 (7A3) and NCI-CoV-8A2 (8A2), which have a high affinity for the RBD via targeting nonoverlapping epitopes and show broad neutralization activity against SARS-CoV-2 and its emerging variants of concern. Cryoelectron microscopy (cryo-EM) complex structures revealed that 8A2 binds the RBD in its up mode with a long CDR3 loop directly involved in the ACE2 binding residues and that 7A3 targets a deeply buried region that uniquely extends from the S1 subunit to the apex of the S2 subunit regardless of the conformational state of the RBD. At a dose of ≥5 mg/kg, 7A3 efficiently protected transgenic mice expressing hACE2 from the lethal challenge of variants B.1.351 or B.1.617.2, suggesting its therapeutic use against COVID-19 variants. The dromedary camel V_HH phage libraries could be helpful as a unique platform ready for quickly isolating potent nanobodies against future emerging viruses.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiologic agent of COVID-19 (1, 2) that enters human cells by binding its envelope anchored type I fusion protein (spike) to angiotensin-converting enzyme 2 (ACE2) (3, 4). The SARS-CoV-2 spike is a trimer of S1/S2 heterodimers with three ACE2 receptor-binding domains (RBDs) attached to the distal end of the spike via a hinge region that allows conformational flexibility (4). In the all-down conformation, the RBDs are packed with their long axes contained in a plane perpendicular to the axis of symmetry of the trimer. Transition to the roughly perpendicular up conformation exposes the receptor-binding motif (RBM), located at the distal end of the RBD, which is sterically occluded in the down state. Numerous neutralizing antibodies targeting the spike, particularly its RBD, have been developed to treat COVID-19 using common strategies such as single B cell cloning, animal immunization, and phage display (5–9). Most vaccines, including those that are messenger RNA based, are designed to induce immunity against the spike or RBD (10–12). However, emerging SARS-CoV-2 variants such as D614G, B.1.1.7 (Alpha, United Kingdom), B.1.351 (Beta, South Africa), and P.1 (Gamma, Brazil) have exhibited increased resistance to neutralization by monoclonal antibodies or postvaccination sera elicited by the COVID-19 vaccines (13, 14). Monoclonal antibodies with Emergency Use Authorization for COVID-19 treatment partially (Casirivimab) or completely (Bamlanivimab) failed to inhibit the B.1.351 and P.1 variants. Similarly, these variants were less effectively inhibited by convalescent plasma and sera from individuals vaccinated with a COVID-19 vaccine (BNT162b2) (13). The B.1.617.2 (Delta, India) variant became the prevailing strain in many countries (15). Highly effective and broadly neutralizing antibody therapy is urgently demanded for COVID-19 patients.Due to their small size and unique conformations, camelid V_HH single-domain antibodies (also known as nanobodies) can recognize protein cavities that are not accessible to conventional antibodies (16). To isolate high-affinity nanobodies without a need for further affinity maturation, it is highly desirable to construct large nanobody libraries with great diversity. Dromedary camels have been found as potential natural reservoirs of Middle East respiratory syndrome CoV (MERS-CoV) (17). We speculated that dromedary camels would be an ideal source of neutralizing nanobodies against coronaviruses. In the present study, we built large camel V_HH single-domain antibody phage libraries with a diversity of over 10¹¹ from six dromedary camels (Camelus dromedarius), three males and three females, with ages ranging from 3 mo to 20 y. We used both the SARS-CoV-2 RBD and the stabilized spike ectodomain trimer protein as baits to conduct phage panning for nanobody screening. Among all the binders, we found NCI-CoV-7A3 (7A3), NCI-CoV-1B5 (1B5), NCI-CoV-8A2 (8A2), and NCI-CoV-2F7 (2F7) to be potent ACE2 blockers. In addition, these dromedary camel nanobodies displayed potent neutralization activity against the B.1.351 and B.1.1.7 variants and the original strain (Wuhan-Hu-1). The cryoelectron microscopy (cryo-EM) structure of the spike trimer protein complex with these V_HH nanobodies revealed two distinct nonoverlapping epitopes for neutralizing SARS-CoV-2. In particular, 7A3 recognizes a unique and deeply buried region that extends to the apex of the S2 subunit of the spike. Combined treatment with 7A3 and 8A2 shows more potent protection against various variants in culture and mice infected with the B.1.351 variant. Interestingly, 7A3 alone retains its neutralization activity against the lethal challenge of the B.1.617.2 variant in mice.     

Performance,Reaction Pathway and Kinetics of the Enhanced Dechlorination Degradation of 2,4-Dichlorophenol by Fe/Ni Nanoparticles Supported on Attapulgite Disaggregated by a Ball Milling–Freezing Process

Attapulgite (ATP) disaggregated by a ball milling–freezing process was used to support Fe/Ni bimetallic nanoparticles (nFe/Ni) to obtain a composite material of D-ATP-nFe/Ni for the dechlorination degradation of 2,4-dichlorophenol (2,4-DCP), thus improving the problem of agglomeration and oxidation passivation of nanoscale zero-valent iron (nFe) in the dechlorination degradation of chlorinated organic compounds. The results show that Fe/Ni nanoparticle clusters were dispersed into single spherical particles by the ball milling–freezing-disaggregated attapulgite, in which the average particle size decreased from 423.94 nm to 54.51 nm, and the specific surface area of D-ATP-nFe /Ni (97.10 m²/g) was 6.9 times greater than that of nFe/Ni (14.15 m²/g). Therefore, the degradation rate of 2,4-DCP increased from 81.9% during ATP-nFe/Ni application to 96.8% during D-ATP-nFe/Ni application within 120 min, and the yield of phenol increased from 57.2% to 86.1%. Meanwhile, the reaction rate K_obs of the degradation of 2,4-DCP by D-ATP-nFe/Ni was 0.0277 min⁻¹, which was higher than that of ATP-nFe/Ni (0.0135 min⁻¹). In the dechlorination process of 2,4-DCP by D-ATP-nFe/Ni, the reaction rate for the direct dechlorination of 2,4-DCP of phenol (k₅ = 0.0156 min⁻¹) was much higher than that of 4-chlorophenol (4-CP, k₂ = 0.0052 min⁻¹) and 2-chlorophenol (2-CP, k₁ = 0.0070 min⁻¹), which suggests that the main dechlorination degradation pathway for the removal of 2,4-DCP by D-ATP-nFe/Ni was directly reduced to phenol by the removal of two chlorine atoms. In the secondary pathway, the removal of one chlorine atom from 2,4-DCP to generate 2-CP or 4-CP as intermediate was the rate controlling step. The final dechlorination product (phenol) was obtained when the dechlorination rate accelerated with the progress of the reaction. This study contributes to the broad topic of organic pollutant treatment by the application of clay minerals.