Strategies for ABO-incompatible liver transplantation / 器官移植

With rapid development of organ transplantation, the issue of global organ shortage has become increasingly prominent. At present, liver transplantation is the most effective treatment for end-stage liver disease. Nevertheless, the shortage of donors has been a key problem restricting the development of liver transplantation. China is a country with a larger number of hepatitis B, and the shortage of donor liver is particularly significant. Many critically ill patients often lose the best opportunity or even die because they cannot obtain a matched donor liver in time. As a strategy to expand the donor pool, ABO-incompatible (ABOi) liver transplantation offers new options for patients who are waiting for matched donors. However, ABOi liver transplantation is highly controversial due to higher risk of complications, such as severe infection, antibody-mediated rejection (AMR), biliary complications, thrombotic microangiopathy, and acute kidney injury, etc. In this article, research progress in preoperative, intraoperative and postoperative strategies of ABOi liver transplantation was reviewed, aiming to provide reference for clinical application and research of ABOi liver transplantation.

Clinical management strategies for recipients with renal graft loss / 器官移植

With the maturity of kidney transplantation, introduction of new immunosuppressive drugs and improvement of immunosuppressive regimen, the short-term survival rate of kidney transplant recipients has been significantly improved, whereas the long-term survival rate has not been significantly elevated. Kidney transplant recipients may have the risk of renal graft loss. Clinical management after renal graft loss is complicated, including the adjustment of immunosuppressive drugs, management of renal graft and selection of subsequent renal replacement therapy. These management procedures directly affect clinical prognosis of patients with renal graft loss. Nevertheless, relevant guidelines or consensuses are still lacking. Clinical management of patients after renal graft loss highly depend upon clinicians’ experience. In this article, the adjustment of immunosuppressive drugs, management of renal graft and selection of subsequent renal replacement therapy were reviewed, aiming to provide reference for prolonging the survival and improving the quality of life of these patients.

Analysis of risk factors related to clinical stage in patients with non-small cell lung cancer / 中国现代医生

@#Objective To investigate the risk factors associated with clinical stage in patients with non-small cell lung cancer(NSCLC).Methods The clinical data of 182 patients with non-small cell lung cancer admitted from July 2019 to March 2023 were retrospectively analyzed,and they were divided into stage Ⅰ,stage Ⅱ group(n=73)and stage Ⅲ,stage Ⅳ group(n=109)according to the clinical stage.Inter-group comparison and Logistic regression analysis were used to screen the risk factors affecting the clinical stage of patients,and receiver operating characteristic(ROC)curve was used to analyze the diagnostic value of these risk factors.Results Antinuclear antibody(ANA),fibrinogen(FIB)and cytokeratin 19 fragment(CYFRA21-1)were independent risk factors affecting the clinical stage of NSCLC patients.The optimal cut-off values of FIB and CYFRA21-1 were 4.07g/L and 7.07μg/L,respectively.The area under curve(AUC)of the combined diagnosis of clinical stage was 0.859,the sensitivity was 64.2％,and the specificity was 95.9％.Conclusion ANA,FIB and CYFRA21-1 are independent risk factors for the progression of clinical stage of NSCLC patients.The combined detection of the three indicators has certain reference value for the diagnosis of clinical stage in NSCLC patients.

The Research Status of Novel Coronavirus Antibodies and Small Molecule Inhibitors / 生物化学与生物物理进展

The World Health Organization has declared that the outbreak of coronavirus disease 2019(COVID-19) is a global pandemic. As mutations occurred in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the global epidemic still needs further concern. Worryingly, the effectiveness and neutralizing activity of existing antibodies and vaccines against SARS-CoV-2 variants is declining. There is an urgent need to find an effective antiviral medication with broad-spectrum inhibitory effects on novel coronavirus mutant strains against the SARS-CoV-2 infection. Neutralizing antibodies play an important role in the prevention and treatment of COVID-19. The interaction of spike-receptor-binding domain (Spike-RBD) of SARS-CoV-2 and human angiotensin-converting enzyme 2 (ACE2) is the first and critical step of SARS-CoV-2 infection. Hence, the SARS-CoV-2 Spike-RBD is a hot target for neutralizing antibodies development. Evusheld, the combination of Tixagevimab and Cilgavimab monoclonal antibodies (mAbs) targeting Spike-RBD exhibits neutralizing activity against BA.2.12.1, BA.4 and BA.5, which could be used as pre-exposure prophylaxis against SARS-CoV-2 infection. The nucleocapsid (N) protein is a conservative and high-abundance structural protein of SARS-CoV-2. The nCoV396 monoclonal antibody, isolated from the blood of convalescent COVID-19 patients against the N protein of SARS-CoV-2. This mAb not only showed neutralizing activity but also inhibits hyperactivation of complement and lung injury induced by N protein. The mAb 3E8 targeting ACE2 showed broadly neutralizing activity against SARS-CoV-2 and D614G, B.1.1.7, B.1.351, B.1.617.1 and P.1 variants in vitro and in vivo, but did not impact the biological activity of ACE2. Compared with neutralizing antibodies, small molecule inhibitors have several advantages, such as broad-spectrum inhibitory effect, low cost, and simple administration methods. Several small-molecule inhibitors disrupt viral binding by targeting the ACE2 and N-terminal domain (NTD) of SARS-CoV-2 spike protein. Known drugs such as chloroquine and hydroxychloroquine could also block the infection of SARS-CoV-2 by interacting with residue Lys353 in the peptidase domain of ACE2. The transmembrane protease serine 2 (TMPRSS2) inhibitors Camostat mesylate and Proxalutamide inhibit infection by blocking TMPRSS2 mediates viral membrane fusion. The main protease inhibitor Paxlovid and RNA-dependent RNA polymerase inhibitor Azvudine have been approved for treatment of COVID-19 patients. This review summarizes the current research status of neutralizing antibodies and small molecule inhibitors and prospects for their application. We expect to provide more valuable information for further studies in this field.

Conformational Engineering of Antibody Fragments on The Surface of Platinum Nanoparticles / 生物化学与生物物理进展

ObjectiveRecent successful restoration of the native conformation and function of the complementary-determining regions (CDRs) of antibodies on gold nanoparticles (AuNPs) demonstrates that the era of molecular conformational engineering is dawning. Basically, molecular conformational engineering aims to precisely tune flexible non-functional molecules into special conformations to carry out novel functions, in the same way as protein folding. In order to explore the general applicability of molecular conformational engineering, as well as to reveal the mechanism of protein structure-function relationship, the objective of this work is to restore the native conformation and function of the CDRs of an antibody on platinum nanoparticles (PtNPs). MethodsThe CDR fragment of the anti-lysozyme antibody cAB-lys3, which has no stable conformation or function in free state, was conjugated onto the surface of PtNPs through two Pt-S bonds. The original antigen-recognizing function of the CDR restored on PtNPs was assessed by the specific inhibition of the enzymatic activity of lysozyme by the PtNP-CDR conjugates. ResultsAfter optimization of the peptide density on the surface of PtNPs and modification of PtNPs with polyethylene glycol (PEG), the resulted PtNP-based hybrid artificial antibody (PtNP-10PEG-30P1), dubbed Platinumbody, could bind specifically to lysozyme and significantly inhibit the activity of lysozyme. ConclusionThis is the first time that the fragment of a protein could refold on PtNPs. Together with the previous Goldbody and Silverbody, current work demonstrates that artificial proteins could be generally created by restoration of the native conformation of natural proteins fragments on NPs.

New Advances in Dato-DXd Treatment for Advanced Non-Small-Cell Lung Cancer / 肿瘤防治研究

Approximately 50% of patients with non-small-cell lung cancer (NSCLC) are diagnosed at advanced stages and face a challenging prognosis despite the integration of targeted therapies, immunotherapy, and systemic chemotherapy into current standard care. A key factor in this context is trophoblast cell-surface antigen 2 (TROP2), which is widely expressed in NSCLC and strongly associated with poor patient outcomes. This article examines the latest developments in the application of datopotamab deruxtecan (Dato-DXd, DS-1062), a novel antibody-drug conjugate targeting TROP2, in the treatment of NSCLC. It provides a detailed assessment of Dato-DXd’s technical design, evaluates its efficacy by using recent clinical trial data, and discusses its safety profile.

New Advances in Treatment of HER2-Low Breast Cancer / 肿瘤防治研究

Currently, breast cancer is a common malignancy in female, and previous guidelines recommended that one of the key biomarkers for breast cancer, human epidermal growth factor receptor 2 (HER2), is classified as either positive or negative to guide clinicians’ treatment decisions. While nearly half of breast cancer patients have low HER2 expression (IHC expression is 1+ or 2+ and ISH detection is negative), such patients are insensitive to traditional anti-HER2 targeted therapy. However, novel antibody-drug conjugates (ADCs) provide new targeted therapy options for breast cancer patients with low HER2 expression, challenging the traditional binary concept and arousing research enthusiasm. In the latest ASCO/CAP guidelines for HER2 detection in breast cancer, HER2-low breast cancer has been included as a clinical treatment subgroup. This article will review the definition of HER2-low breast cancer, the progress of drug therapy such as ADC, and the current challenges faced by this subgroup.

Research Progress on Mechanisms and Optimization Methods for Toxicity Induced by Antibody–Drug Conjugates / 肿瘤防治研究

Since the approval of gemtuzumab ozogamicin, an antibody–drug conjugate (ADC) targeting CD33 in 2000, 13 ADC drugs have been approved by the FDA. Although these drugs have clearly improved the survival of patients with various types of advanced cancers, their significant toxicity has compromised their therapeutic benefits. The adverse reactions of ADC drugs are complex and include on-target and off-target toxicities, where the payload drug is a determining factor. Antibody and linker may also affect the degree of toxicity. Combination therapy becomes an important strategy in anticancer treatment because of its increased efficiency, but treatment-related adverse reactions also increase accordingly. This review comprehensively analyzes the toxicity mechanisms of current ADC drugs and proposes various optimization strategies, including but not limited to optimizing linker molecules, upgrading antibody design, and changing drug administration strategies, to improve the overall safety profile of ADC drugs.

Prokaryotic expression of variable region protein of adeno-associated virus 9 capsid and preparation of polyclonal antibody / 中国生物制品学杂志

@#Objective To express and purify the protein of variable region of adeno-associated virus 9(AAV9) capsid in prokaryotic cells,and prepare rabbit polyclonal antibody against it.Methods DNA sequence encoding variable region of AAV9 capsid protein was designed,synthesized and inserted into prokaryotic expression vector pET-30a. The obtained plasmid pET-30a-AAV-VR was transformed to E.coli BL21(DE3),induced by IPTG to express the multivalent antigenic peptide and purified by Ni-NTA resin under denaturation conditions. Male Japanese large-eared white rabbits were immunized with the AAV9 variable region protein after dialysis and renaturation to prepare polyclonal antibody,which was determined for the antibody potency by indirect ELISA,and for the specificity by Western blot and cellular immunofluorescence.Results The recombinant prokaryotic expression plasmid pET-30a-AAV-VR expressing the variable region of AAV9 capsid was constructed correctly as identified by XhoⅠ and BglⅡ digestion. The expressed protein was recognized by His tag antibody after purification with a relative molecular mass of about 20 000. The potency of rabbit polyclonal antibody was 1∶10 240 000,which specifically recognize AAV9 capsid protein.Conclusion The capsid variable region protein of AAV9 was successfully expressed and rabbit polyclonal antibody with high potency was prepared,which laid a foundation of the subsequent development of AAV vector and the research of AAV biological function.

Development and verification of a reporter gene determination assay for ADCP potency of IgG2 anti-EGFR monoclonal antibody based on DOE / 中国生物制品学杂志

@#Objective To develop and verify a reporter gene assay for the determination of antibody dependent cellular phagocytosis(ADCP)potency of Ig G2 monoclonal antibody(m Ab)against epidermal growth factor receptor(EGFR)by combining Design of Experiment(DOE)and one factor at a time(OFAT).Methods The Jurkat/NFAT-Re/FcγRⅡa stably transformed cell line was used as effector cells,while the A431 cell line as the target cells.The JMP software was used to optimize the seven key factors in the experiment by combining DOE and OFAT analysis,while the ratio of upper and lower asymptotes(D/A)was used as the statistic,and the reporter gene method was developed to evaluate the ADCP potency of Ig G2 anti-EGFR m Ab.The method was verified according to the general chapter<9401>of Chinese Pharmaco-poeia（Ⅲ/Ⅳvolume,2020 edition)and used to determine the biological potency of Ig G2 anti-EGFR m Ab injection.Results After three rounds of experiments,the reporter gene method to evaluate the ADCP potency of Ig G2 anti-EGFR m Ab was developed.The method showed a dose-response relationship and was consistent with the four-parameter regression equa-tion y=(A-D）/[1+(x/C)~B]+D.The range of seven key conditions was determined:the density of effector cells was(1.25-3.75）×10~4 cells/well,the density ratio of effector cells to target cells was 1.0-2.0,the incubation time of target cells was 20-40 min,the incubation time of administration was 15-30 min,the total time was 5.5-6.5 h,and the color time was 5-30 min with luciferase detection system(Bright-Glo)as the color agent.The method had good specificity.Six independent tests were run for the five potency levels,with the correlation coefficient r of 0.994 5 and the linear regression equation slope of 1.02.The relative potency of five potency levels respectively was(62.15±1.38)%,(78.53±2.82)%,(99.12±3.95)%,(123.27±4.59)%and(155.22±7.04)%,the range of relative biases was-2.9%-0.2%,and the range of generalized cross-validation(GCV)was 2.2%-4.6%.The method had good linearity,relative accuracy and precision in the range of 64%-156%.The mean value of the potency of IgG2 anti-EGFR m Ab in three tests was(101.5±2.8)%.Conclusion The reporter gene assay developed in this study can be used to evaluate the ADCP potency of IgG2 anti-EGFR mAb

Antibody identification and analysis of 80 children with positive platelet antibody in initial screening / 中国输血杂志

【Objective】 To explore the distribution and types of platelet antibodies in children with positive platelet antibody in initial screening. 【Methods】 Blood samples of 80 pediatric patients who applied for platelet transfusion in our hospital from September 2021 to May 2022 and tested positive for platelet antibodies were identified using the PAKPLUS kit for antibody identification, and the distribution of HLA and HPA antibodies were analyzed. 【Results】 Among the 80 reactive samples in initial screening, 9 were negative, 71 were positive. Among the 71 positive cases, 1 was HLA-Ⅰantibody positive(1.41%, 1/71), 21 were HPA antibody positive (29.58%, 21/71), and 49 were both HLA-Ⅰ antibody and HPA antibody positive(69.01%, 49/71). Among the 70 HPA positive cases, 23.95% (17/71) had a single HPA antibody, with 18.31% (13/71) of anti GP Ⅱb/Ⅲa, 2.82% (2/71) of anti GP Ⅰa/Ⅱa, 2.82% (2/71) of anti GP Ⅳ and 0% (0/71) of anti GP Ⅰb/Ⅸ, while 74.65% (53/71) presented multiple HPA antibodies. No statistically significant difference was found in antibody distribution among age, gender, transfusion history and disease types. 【Conclusion】 HLA-Ⅰ antibody combined with HPA antibody are the main types of platelet antibodies among children with positive platelet antibodies. Anti-GPⅡb/Ⅲa accounted for the largest proportion of HPA antibodies. Antibody distribution is not releted to age, gender, history of blood transfusion and disease types.

Identification of anti-Jra antibodies by serology and mass spectrometry / 中国输血杂志

【Objective】 To report the antibody specific identification process of a pregnant woman who had no history of blood transfusion but presented high-frequency anti-Jra antibodies. 【Methods】 Antibody screening and identification were performed by saline and indirect Coomb’s technique (microcolumn gel card, PEG). ABO, Rh and other blood group antigens were identified by saline. Further antibody identification tests were performed by the reaction between cells treated with various enzymes and patient plasma. Jra antigen was identified by human anti-Jra antibody. JR blood type genotyping was performed by MALDI-TOF mass spectrometry detection system. Antibody titer in serum was tested. 【Results】 The patient′s blood type was O with RhD(+ ) and CcDEe. The plasma reacted negatively with antibody screening and identification cells by saline, but positively by indirect globulin test. The self-control was negative. The patient′s Jra antigen was negative in serological tests and mass spectrometry blood type genotyping. Mass spectrometry revealed a homozygous nonsense mutation (c.376C>T) in exon 4. The anti-Jra antibody titer was 1∶2. 【Conclusion】 The patient developed high-frequency anti-Jra antibodies during pregnancy.

Multiple antibodies against -E, -c, -M, and -S: a case report / 中国输血杂志

【Objective】 To identify antibody specificity in an elderly patient with hydronephrosis accompanied by ureteral stones and shock who had multiple antibodies. 【Methods】 Microcolumn gel method was used to screen unexpected antibodies of red blood cells and identify antibodies. Enzyme method and antibody absorption method were used to help judge the specificity of antibodies in patients.The ABO blood type, Rh blood type and MNS blood type of patient were determined by saline tube method. 【Results】 The patient′s blood types were O, CCDee, NNss, and a combination of anti-E, anti-c, anti-M and anti-S antibodies was detected. 【Conclusion】 Repeated blood transfusion may lead to the presence of one or more unexpected antibodies in patients. Patients with multiple or high-frequency antibodies may experience difficulties in identification and delayed blood use.

Changes in perioperative blood group antibody of 33 type-A/B recipients in ABO-incompatible kidney transplantation / 中国输血杂志

【Objective】 To statistically analyze the perioperative results of patients with ABO-incompatible kidney transplantation (ABOi-KT), in order to explore the changes in blood group antibody of type-A/B recipients. 【Methods】 A total of 33 cases of blood group A/B ABOi-KT recipients in our hospital from January 2021 to October 2023 were recruited and divided into two groups of group A(n=18) and group B(n=15) according to the different blood types of recipient. The effects of preoperative plasmapheresis on antibody titer, antibody rebound and renal function after operation(serum urea nitrogen, creatinine and estimated glomerular filtration rate on the 1st, 3rd, 7th and 14th day) were analyzed between the two groups. According to the postoperative rebound of blood type antibodies, 33 recipients were divided into antibody rebound group(n=7) and non rebound group(n=26), and the differences in initial blood type antibody titers between the two groups were analyzed. 【Results】 There was no significant difference in the clearance rate of IgM with preoperative plasma exchange between the two groups (Z=-0.26, P>0.05); Levels of serum urea nitrogen and creatinine on the 1st, 3rd, 7th and 14th day after operation between group A and group B were not statistically significant(P>0.05), the same as eGFR. Group B was more prone to rebound antibody compared with group A (P0.05) between the two groups was found. 【Conclusion】 The patients type B receiving type AB kidney donors are more prone to rebound antibody after ABOi-KT operation compared to the the patients type A receiving type AB.

Correlation between unexpected antibody types and transfusion efficacy in patients with autoimmune hemolytic anemia (AIHA) / 中国输血杂志

【Objective】 To analyze the antibody types of autoimmune hemolytic anemia(AIHA) patients in Panyu district, Guangzhou and track the therapeutic effect of blood transfusion, so as to provide reference for clinical transfusion treatment strategy of AIHA patients. 【Methods】 From January 2021 to October 2023, 96 ambiguous cross-matching blood samples from Blood Transfusion Departments of local hospitals sent to Panyu Central Blood Station were analyzed, and 25 samples of AIHA patients were identified. Then blood group identification, Rh system antigen phenotyping, antibody screening and cross-matching were further performed to analyze the correlation between antibody types and transfusion efficacy in AIHA patients. 【Results】 Among the 25 samples of AIHA patients, 17 showed consistency between forward and reverse blood grouping and 8 showed discrepancy. There were 19 (19/25, 76%) samples incompatible in cross match on the major side, of which 18 (18/19, 94.7%) were positive for direct Coombs test, autoantibodies and non-specific antibodies, and 1 (1/19, 5.3%)was positive for autoantibody and alloantibody.There were 6 (6/25, 24%) samples compatible in cross match on the major side, of which 3 (3/6, 50%) were positive for autoantibodies, 3 (3/6, 50%) were positive for autoantibody and alloantibody. Of the 25 AIHA patients, 20 received blood transfusion treatment and could be traced, and 5 patients did not receive blood transfusion treatment or transferred to other hospitals and could not be traced. Blood transfusion was effective in 11 (11/20, 55%) cases, partially effective in 6 (6/20, 30%) cases, and ineffective in 3 (3/20, 15%) cases. Among the ABO blood group incompatibility samples, transfusion was effective or partially effective in 17 (17/20, 85%) cases. 【Conclusion】 The transfusion efficacy of AIHA patients is not directly related to the results of cross-matching. Under the premise of regulating the autoimmune environment and eliminating the ABO blood group incompatibility caused by unexpected alloantibodies, AIHA patients with incompatible cross-matching can be transfused when necessary, and transfusion of ABO and Rh system antigen homologous blood can improve the safety and efficiency of transfusion.

Expert consensus on screening for unexpected red blood cell antibodies / 中国输血杂志

Unexpected red blood cell antibodies refer to antibodies except for anti-A and anti-B in normal ABO blood group, and are widely present in patients with pregnancy, transfusion, transplantation, injection of immunogenic substances, or autoimmune diseases, leading to difficulties in blood type identification and cross matching test, which seriously affect transfusion safety and efficacy. This consensus aims to further standardize the requirements, operating procedures and clinical significance of antibody screening, thus improving the safety and efficacy of blood transfusion.

Application of anti-idiotypic antibodies in antibody screening and crossmatch tests of patients treated with CD47 monoclonal antibody / 中国输血杂志

【Objective】 To perform pre-transfusion examination and major crossmatch test using CD47 anti-idiotypic antibody (CD47 AID) (method 1) and reagent lack of anti-IgG4 anti-human globulin(method 2) in patients treated with CD47 monoclonal antibodies, and evaluate the feasibility of method 1 by comparing the transfusion efficacy of patients after cross matching with two methods. 【Methods】 Post-drug samples were collected from 18 clinical subjects treated with CD47 monoclonal antibody in our hospital. Antibody screening and major crossmatch test were performed using method 1 and method 2, and the difference of ΔHb (post-transfusion Hb minus pre-transfusion Hb) was compared after transfusion. The differences in ΔHb after transfusion were analyzed between the test group using method 1 and the control group without CD47 monoclonal antibody using ordinary microcolumn gel method. 【Results】 There was no significant difference in ΔHb between the test group using method 1 and test group using method 2 (8.40±0.71 vs 7.36±0.94, P>0.05). No significant difference was noticed in ΔHb between the test group using method 1 and the control group without CD47 monoclonal antibody (8.40±0.71 vs 6.59±0.77, P>0.05). 【Conclusion】 In the test group, major crossmatch test with method 1 has the same transfusion efficacy as the test with method 2. Method 1 is simple and easy to operate, and the results are objective and accurate. It is recommended to use method 1 for pre-transfusion antibody screening and major crossmatch tests for patients using CD47 monoclonal antibody.

Application and Research Progress of 225Ac in Tumor Targeted Treatment / 中山大学学报(医学科学版)

225Ac has high linear energy transfer， suitable half-life， short particle range， and good coordination ability， making it one of the promising alpha emitters in targeted radioisotope therapy for tumors， and it has significant research value. This article briefly introduces the physical and chemical properties of 225Ac， as well as common chelating agents （prostate-specific membrane antigen， octreotide， nano-carriers， etc.）. It reviews the applications of targeted drugs labeled with 225Ac in tumors， based on peptides or small molecules as targeting agents， monoclonal antibodies or proteins as targeting molecules， and nano-carriers. It also analyzes the value of its application in therapy， summarizes the methods of labeling with 225Ac and the selection of suitable chelating agents， improvements in targeting specificity， and toxicity side effects. Furthermore， it looks forward to the localization of 225Ac production to meet future clinical needs， in order to provide reference for the subsequent development of 225Ac-labeled drugs.

In vitro study of immunocompatibility of humanized genetically modified pig erythrocytes with human serum / 器官移植

<b>Objective</b> To investigate the differences and the immunocompatibility of wild-type (WT), four-gene modified (TKO/hCD55) and six-gene modified (TKO/hCD55/hCD46/hTBM) pig erythrocytes with human serum. <b>Methods</b> The blood samples were collected from 20 volunteers with different blood groups. WT, TKO/hCD55, TKO/hCD55/hCD46/hTBM pig erythrocytes, ABO-compatible (ABO-C) and ABO-incompatible (ABO-I) human erythrocytes were exposed to human serum of different blood groups, respectively. The blood agglutination and antigen-antibody binding levels (IgG, IgM) and complement-dependent cytotoxicity were detected. The immunocompatibility of two types of genetically modified pig erythrocytes with human serum was evaluated. <b>Results</b> No significant blood agglutination was observed in the ABO-C group. The blood agglutination levels in the WT and ABO-I groups were higher than those in the TKO/hCD55 and TKO/hCD55/hCD46/hTBM groups (all <i>P</i><0.001). The level of erythrocyte lysis in the WT group was higher than those in the ABO-C, TKO/hCD55 and TKO/hCD55/hCD46/hTBM groups. The level of erythrocyte lysis in the ABO-I group was higher than those in the TKO/hCD55 and TKO/hCD55/hCD46/hTBM groups (both <i>P</i><0.01). The pig erythrocyte binding level with IgM and IgG in the TKO/hCD55 group was lower than those in the WT and ABO-I groups. The pig erythrocyte binding level with IgG and IgM in the TKO/hCD55/hCD46/hTBM group was lower than that in the WT group and pig erythrocyte binding level with IgG was lower than that in the ABO-I group (all <i>P</i><0.05). <b>Conclusions</b> The immunocompatibility of genetically modified pig erythrocytes is better than that of wild-type pigs and close to that of ABO-C pigs. Humanized pig erythrocytes may be considered as a blood source when blood sources are extremely scarce.

Expression of Gn protein of severe fever with thrombocytopenia syndrome virus and its immunogenicity / 中国生物制品学杂志

@#Objective To express the Gn protein of severe fever with thrombocytopenia syndrome virus(SFTSV) through adeno-associated virus 9(AAV9) expression system and evaluate its immunogenicity.Methods SFTSV Gn gene was inserted into viral vector pAAV-CMV-FH and the recombinant plasmid was transfected into HEK293T cells to obtain recombinant virus AAV9-Gn.The expression of Gn protein was determined by immunofluorescence and Western blot.Eighteen fernale BALB/c mice were randomly divided into three groups:Mock group(serum-free DMEM),AAV9-GFP group(1 × 10~(11) vg) and AAV9-Gn group(1 × 10~(11) vg),all of which were injected intramuscularly into the right hind limb at a dose of 100 μL per mouse.The body mass,diet,behavior and mental state of mice in each group were monitored continuously for 21 d,and the change rate of body mass was calculated;At 2,4,8 and 16 weeks after immunization,the levels of SFTSV neutralizing antibody in serum of mice in each group were detected by fluorescent reduction neutralization test(FRNT),and the levels of specific IgGl and IgG2a in serum of mice in AAV9-Gn group were detected by ELISA.Results After incubation with specific antibody,Vero cells transfected with AAV9-Gn showed specific green fluorescence under fluorescence microscope,and had specific binding to mouse anti-SFTSV Gn monoclonal antibody,and the specific binding bands were found at a relative molecular mass of about 61 000.The body mass of the three groups showed an increasing trend,there was no significant difference between the three groups(F=0.158—2.621,P> 0.05),and the diet,behavior and mental state were normal.At 2,4,8 and 16 weeks after immunization,the titer of SFTSV neutralizing antibody in serum of mice in AAV9-Gn group was significantly higher than that of Mock group and AAV9-GFP group(H=13.332—14.538,each P <0.001),and the titer peak appeared at 8 weeks;The level of specific IgG1 in serum of mice was significantly higher than that of IgG2a(F=4.373—12.975,each P <0.05) at different time points.Conclusion SFTSV Gn protein can be expressed correctly through AAV9 expression system,and has low toxicity to mice with good immunogenicity,which is expected to be a candidate component of SFTSV vaccine.