Plant bioreactor is a new production platform for expression of recombinant protein, which is one of the cores of molecular farming. In this study, the anti DYKDDDDK (FLAG) antibody was recombinantly expressed in tobacco (Nicotiana benthamiana) and purified. FLAG antibody with high affinity was obtained after immunizing mice for several times and its sequence was determined. Based on this, virus vectors expressing heavy chain (HC) and light chain (LC) inoculated into Nicotiana benthamiana leaves by using Agrobacterium-mediated delivery. Accumulation of the HC and LC was analyzed by SDS/PAGE followed by Western blotting probed with specific antibodies from 2 to 9 days postinfiltration (dpi). Accumulation of the FLAG antibody displayed at 3 dpi, and reached a maximum at 5 dpi. It was estimated that 66 mg of antibody per kilogram of fresh leaves could be obtained. After separation and purification, the antibody was concentrated to 1 mg/mL. The 1:10 000 diluted antibody can probe with 1 ng/mL FLAG fused antigen well, indicating the high affinity of the FLAG antibody produced in plants. In conclusion, the plant bioreactor is able to produce high affinity FLAG antibodies, with the characteristics of simplicity, low cost and highly added value, which contains enormous potential for the rapid and abundant biosynthesis of antibodies.
Animals ; Mice ; Antibodies ; Nicotiana/genetics* ; Agrobacterium/genetics* ; Bioreactors ; Blotting, Western

Objective To prepare mouse monoclonal antibodies against the ectodomain of E2 (E2ecto) glycoprotein of Western equine encephalitis virus (WEEV). Methods A prokaryotic expression plasmid pET-28a-WEEV E2ecto was constructed and transformed into BL21 (DE3) competent cells. E2ecto protein was expressed by IPTG induction and presented mainly as inclusion bodies. Then the purified E2ecto protein was prepared by denaturation, renaturation and ultrafiltration. BALB/c mice were immunized with the formulated E2ecto protein using QuickAntibody-Mouse5W as an adjuvant via intramuscular route, boosted once at an interval of 21 days. At 35 days post-immunization, mice with antibody titer above 1×10⁴ were inoculated with E2ecto intraperitoneally, and spleen cells were fused with SP2/0 cells three days later. Hybridoma cells secreting specific monoclonal antibodies were screened by the limited dilution method, and ascites were prepared after intraperitoneal inoculation of hybridoma cells. The subtypes and titers of the antibodies in ascites were assayed by ELISA. The biological activity of the mAb was identified by immunofluorescence assay(IFA) on BHK-21 cells which were transfected with eukaryotic expression plasmid pCAGGS-WEEV-CE3E2E1. The specificity of the antibodies were evaluated with E2ecto proteins from EEEV and VEEV. Results Purified WEEV E2ecto protein was successfully expressed and obtained. Four monoclonal antibodies, 3G6G10, 3D7G2, 3B9E8 and 3D5B7, were prepared, and their subtypes were IgG2c(κ), IgM(κ), IgM(κ) and IgG1(κ), respectively. The titers of ascites antibodies 3G6G10, 3B9E8 and 3D7G2 were 10⁵, and 3D5B7 reached 10⁷. None of the four antibody strains cross-reacted with other encephalitis alphavirus such as VEEV and EEEV. Conclusion Four strains of mouse mAb specifically binding WEEV E2ecto are successfully prepared.
Horses ; Animals ; Mice ; Encephalitis Virus, Western Equine ; Ascites ; Immunosuppressive Agents ; Antibodies, Monoclonal ; Immunoglobulin M

BACKGROUND

The Philippines is hyperendemic for hepatitis B infection. Vaccination is crucial for protection. Local data on the antibody response after completion of the primary vaccination series is limited.

This study aimed to measure the anti-HBs levels among college students who completed primary hepatitis B vaccination series, compare seropositivity across stratified groups and correlate anti-HBs levels with the time elapsed since the last vaccine dose.

This cross-sectional study included 111 college students in health-related courses with immunization record showing the complete primary Hepatitis B vaccination series. Participants were stratified based on the following vaccination schedules: 0-1-6-month group; 0-1-2-month group; and booster group. Anti-HBs titers were determined.

Statistical analyses included One-way ANOVA, Kruskal-Wallis test, Fisher’s Exact test and Shapiro-Wilk normality test. Kaplan-Meier Survival Estimate assessed the probability of anti-HBs seropositivity over time. Data were analyzed using STATA 13.1.

The baseline characteristics of the study population were homogenous. The median anti-HBs titer several years after primary vaccination was low at 2.9 mIU/mL. Participants in the booster group had the highest seropositivity rate (57.14%) with a median titer of 30.16 mIU/mL. There was an inverse relationship between anti-HBs titer and elapsed time since the last vaccine dose. Kaplan-Meier Survival Estimate showed that the seropositivity decreases to 90.56% after 15.8 years, 51.3% after 17.5 years, and 2.97% at 18 years.

This study revealed low anti-HBs titers among students who previously completed primary vaccination series, with no significant difference between two schedules. Booster doses resulted in the highest seropositivity. Over-all, seropositivity declines over time.

BACKGROUND

Pre-transfusion testing is done to avoid transfusion morbidity from unexpected RBC antibodies. Available commercial kits from Western brands may not consider racial differences in antibody frequencies between East/Southeast Asians and Western populations. The limited number of blood banks in the Philippines precludes research on RBC antibody screening and identification in the country.

This study aimed to compare RBC antibody screening and identification methods in patients at a tertiary hospital in the Philippines, assess the frequency of major blood group antibodies using both techniques, and review clinical histories of discrepant and nonspecific cases.

Retrospective review showed 118 cases with both screening and identification tests using both conventional tube-based technique and column agglutination or gel-based technique. Antibody frequencies and discrepant or nonspecific results were recorded. Concordance rates were calculated, and differences between the two methods were analyzed using 95% confidence interval (95% CI). Clinical histories of discrepant and nonspecific cases were also reviewed.

The most frequent major blood group was Rh (41 cases or 34.7%), followed by MNS (34 cases or 28.8%) and Kidd (15 cases or 12.7%). The most common antibody was Anti-E (24 cases or 20.3%), followed by Anti-Mia (19 cases or 16.1%), and Anti-M and Anti-c (12 cases each, or 10.2% each). The concordance rate for screening was statistically significant at 72%. Concordance rate for identification was 59.3%, with significant difference in identifying Anti-Mia. Clinical histories for discrepant or nonspecific cases showed previous transfusions, pregnancy, lymphoproliferative conditions, and certain medications.

Statistically significant differences between the two methods were found, with the gel-based technique identifying more Anti-Mia cases. Negative results from the tube-based method do not fully exclude Anti-Mia. These discrepancies highlight the benefit of using both methods for comprehensive RBC antibody screening and identification, done as a complement to the other.

Hypoglycemic disorders are rare in persons without diabetes, and clinical evaluation to identify its etiology can be challenging. We present a case of insulin autoimmune syndrome induced by carbimazole in a middle-aged Chinese man with underlying Graves’ disease, which was managed conservatively with a combination of dietary modification and alpha-glucosidase inhibitor.
Hypoglycemia ; Hyperinsulinism ; Insulin Antibodies

Humans ; Consensus ; East Asian People ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Hepatitis B/virology* ; Hepatitis B Antibodies ; Hepatitis B Surface Antigens ; Hepatitis B virus/physiology* ; Virus Activation ; Latent Infection/virology*

Humans ; Vaccines, Inactivated ; COVID-19/prevention & control* ; Vaccination ; Viral Vaccines ; Immunity ; Antibodies, Viral

OBJECTIVE: The prevalence and related factors of serum anti-HCV in different regions and hospitals have not been studied extensively in China. We used routine screening data to determine the prevalence of HCV antibody in hospital patients, evaluate the epidemic trend of hepatitis C and formulate screening strategies. METHODS: Patient information and HCV antibody testing results were collected from January 2017 to December 2019 in 77 HCV sentinel hospitals in China. Univariate and multivariate logistic regression was used to determine the characteristics and associations. RESULTS: HCV antibody prevalence rates were distinct among patients in different departments, with a range of 0.33%-6.93%. Patients who were admitted to the liver disease-related departments (a OR = 10.76; 95% CI, 10.27-11.28), Internal Medicine (a OR = 2.87; 95% CI, 2.75-3.00), and Department of Surgery (a OR = 1.95; 95% CI, 1.87-2.04), were more likely to be tested for HCV antibody positive. HCV antibody prevalence was associated with patients aged 45 years and older (a OR = 2.74; 95% CI, 2.69-2.80), testing in infetious disease hospitals (a OR = 2.33; 95% CI, 2.26-2.40) and secondary hospitals (a OR = 1.72; 95% CI, 1.69-1.75). Patients in sentinel hospitals of the Northeast (a OR = 12.75; 95% CI, 12.40-13.11), the Central (a OR = 1.65; 95% CI, 1.61-1.70), and the West (a OR = 1.78; 95% CI, 1.73-1.83) China had higher HCV prevalence than those who were in the Eastern coastal area. CONCLUSION Those who were over 45 years old and saw doctors for liver diseases, and invasive diagnosis and treatment should be referred to HCV antibody testing.
Humans ; Middle Aged ; Prevalence ; Hepatitis C/complications* ; Hepacivirus ; Hospitals ; Hepatitis C Antibodies ; China/epidemiology* ; Risk Factors

OBJECTIVE: To investigate whether Omicron BA.1 breakthrough infection after receiving the SARS-CoV-2 vaccine could create a strong immunity barrier. METHODS: Blood samples were collected at two different time points from 124 Omicron BA.1 breakthrough infected patients and 124 controls matched for age, gender, and vaccination profile. Live virus-neutralizing antibodies against five SARS-CoV-2 variants, including WT, Gamma, Beta, Delta, and Omicron BA.1, and T-lymphocyte lymphocyte counts in both groups were measured and statistically analyzed. RESULTS: The neutralizing antibody titers against five different variants of SARS-CoV-2 were significantly increased in the vaccinated population infected with the Omicron BA.1 variant at 3 months after infection, but mainly increased the antibody level against the WT strain, and the antibody against the Omicron strain was the lowest. The neutralizing antibody level decreased rapidly 6 months after infection. The T-lymphocyte cell counts of patients with mild and moderate disease recovered at 3 months and completely returned to the normal state at 6 months. CONCLUSION Omicron BA.1 breakthrough infection mainly evoked humoral immune memory in the original strain after vaccination and hardly produced neutralizing antibodies specific to Omicron BA.1. Neutralizing antibodies against the different strains declined rapidly and showed features similar to those of influenza. Thus, T-lymphocytes may play an important role in recovery.
Humans ; Antibodies, Neutralizing ; Prospective Studies ; SARS-CoV-2 ; Breakthrough Infections ; COVID-19 Vaccines ; COVID-19 ; T-Lymphocytes ; China/epidemiology* ; Antibodies, Viral

CLDN6 is a member of the CLDNs family that is specifically and highly expressed in cancers such as ovarian, testicular, endocervical, liver and lung adenocarcinoma, but hardly expressed in adult normal tissues. CLDN6 is able to activate multiple signaling pathways, which take part in the development and progression of cancer, including promoting tumor growth, migration and invasion, and promoting chemoresistance in cancer. In recent years, CLDN6 has received much attention as a novel target for cancer therapeutics. Many types of anticancer drugs targeting CLDN6 have been developed, including antibody-conjugated drugs (ADC), monoclonal antibodies, bispecific antibodies, and chimeric antigen receptor T-cell immunotherapy (CAR-T). This paper briefly summarizes the structure, expression and function of CLDN6 in tumors, and reviews the current status and ideas of developing targeted CLDN6 anticancer drugs.
Signal Transduction ; Immunotherapy ; Antibodies, Monoclonal ; Neoplasms/drug therapy*