Animals ; Antibodies, Neutralizing/biosynthesis* ; Antibodies, Viral/biosynthesis* ; Body Weight/immunology* ; COVID-19/virology* ; Disease Models, Animal ; Disease Progression ; Humans ; Immunohistochemistry ; Lung/virology* ; Male ; Mesocricetus ; Nasal Cavity/virology* ; RNA, Viral/immunology* ; SARS-CoV-2/pathogenicity* ; Severity of Illness Index ; Viral Load

Objective: The coronavirus disease 2019 (COVID-19) pandemic continues to present a major challenge to public health. Vaccine development requires an understanding of the kinetics of neutralizing antibody (NAb) responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methods: In total, 605 serum samples from 125 COVID-19 patients (from January 1 to March 14, 2020) varying in age, sex, severity of symptoms, and presence of underlying diseases were collected, and antibody titers were measured using a micro-neutralization assay with wild-type SARS-CoV-2. Results: NAbs were detectable approximately 10 days post-onset (dpo) of symptoms and peaked at approximately 20 dpo. The NAb levels were slightly higher in young males and severe cases, while no significant difference was observed for the other classifications. In follow-up cases, the NAb titer had increased or stabilized in 18 cases, whereas it had decreased in 26 cases, and in one case NAbs were undetectable at the end of our observation. Although a decreasing trend in NAb titer was observed in many cases, the NAb level was generally still protective. Conclusion We demonstrated that NAb levels vary among all categories of COVID-19 patients. Long-term studies are needed to determine the longevity and protective efficiency of NAbs induced by SARS-CoV-2.
Adult ; Aged ; Aged, 80 and over ; Antibodies, Neutralizing/immunology* ; Antibodies, Viral/immunology* ; COVID-19/immunology* ; Female ; Humans ; Kinetics ; Male ; Middle Aged ; Neutralization Tests ; SARS-CoV-2

Antibodies, Neutralizing ; Antibodies, Viral/isolation & purification* ; B-Lymphocytes/virology* ; COVID-19/virology* ; Humans ; Immunity/genetics* ; RNA, Viral/immunology* ; SARS-CoV-2/pathogenicity* ; Single-Cell Analysis

Antibodies, Neutralizing/immunology* ; Antibodies, Viral/immunology* ; COVID-19/virology* ; COVID-19 Vaccines/immunology* ; Humans ; SARS-CoV-2/pathogenicity* ; Spike Glycoprotein, Coronavirus/immunology* ; Vaccines, Inactivated/immunology*

The ongoing pandemic of Coronavirus disease 19 (COVID-19) is caused by a newly discovered β Coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). How long the adaptive immunity triggered by SARS-CoV-2 can last is of critical clinical relevance in assessing the probability of second infection and efficacy of vaccination. Here we examined, using ELISA, the IgG antibodies in serum specimens collected from 17 COVID-19 patients at 6-7 months after diagnosis and the results were compared to those from cases investigated 2 weeks to 2 months post-infection. All samples were positive for IgGs against the S- and N-proteins of SARS-CoV-2. Notably, 14 samples available at 6-7 months post-infection all showed significant neutralizing activities in a pseudovirus assay, with no difference in blocking the cell-entry of the 614D and 614G variants of SARS-CoV-2. Furthermore, in 10 blood samples from cases at 6-7 months post-infection used for memory T-cell tests, we found that interferon γ-producing CD4
Adaptive Immunity/physiology* ; Adult ; Aged ; Antibodies, Neutralizing/blood* ; COVID-19/immunology* ; Cohort Studies ; Female ; Humans ; Immunoglobulin G/blood* ; Male ; Middle Aged ; SARS-CoV-2/immunology* ; T-Lymphocytes/physiology* ; Time Factors ; Viral Proteins/immunology*

A human immunodeficiency virus type-1 (HIV-1) vaccine which is able to effectively prevent infection would be the most powerful method of extinguishing pandemic of the acquired immunodeficiency syndrome (AIDS). Yet, achieving such vaccine remains great challenges. The membrane-proximal external region (MPER) is a highly conserved region of the envelope glycoprotein (Env) gp41 subunit near the viral envelope surface, and it plays a key role in membrane fusion. It is also the target of some reported broadly neutralizing antibodies (bNAbs). Thus, MPER is deemed to be one of the most attractive vaccine targets. However, no one can induce these bNAbs by immunization with immunogens containing the MPER sequence(s). The few attempts at developing a vaccine have only resulted in the induction of neutralizing antibodies with quite low potency and limited breadth. Thus far, vaccine failure can be attributed to various characteristics of MPER, such as those involving structure and immunology; therefore, we will focus on these and review the recent progress in the field from the following perspectives: (1) MPER structure and its role in membrane fusion, (2) the epitopes and neutralization mechanisms of MPER-specific bNAbs, as well as the limitations in eliciting neutralizing antibodies, and (3) different strategies for MPER vaccine design and current harvests.
AIDS Vaccines ; chemistry ; immunology ; Antibodies, Neutralizing ; immunology ; HIV Antibodies ; immunology ; HIV Envelope Protein gp41 ; immunology ; HIV-1 ; chemistry ; immunology ; Humans

OBJECTIVETo eliminate the side effects of aluminum adjuvant and His-tag, we constructed chimeric VLPs displaying the epitope of EV71 (SP70) without His-tagged. Then evaluating whether the VLPs could efficiently evoke not only humoral but also cellular immune responses against EV71 without adjuvant.

METHODSThe fusion protein was constructed by inserting SP70 into the MIR of truncated HBcAg sequence, expressed in E. Coli, and purified through ion exchange chromatography and density gradient centrifugation. Mice were immunized with the VLPs and sera were collected afterwards. The specific antibody titers, IgG subtypes and neutralizing efficacy were detected by ELISA, neutralization assay, and EV71 lethal challenge. IFN-γ and IL-4 secreted by splenocytes were tested by ELISPOT assay.

RESULTSHBc-SP70 proteins can self-assemble into empty VLPs. After immunization with HBc-SP70 VLPs, the detectable anti-EV71 antibodies were effective in neutralizing EV71 and protected newborn mice from EV71 lethal challenge. There was no significant difference for the immune efficacy whether the aluminum adjuvant was added or not. The specific IgG subtypes were mainly IgG1 and IgG2b and splenocytes from the mice immunized produced high levels of IFN-γ and IL-4.

CONCLUSIONThe fusion proteins without His-tagged was expressed and purified as soluble chimeric HBc-SP70 VLPs without renaturation. In the absence of adjuvant, they were efficient to elicit high levels of Th1/Th2 mixed immune response as well as assisted by aluminum adjuvant. Furthermore, the chimeric VLPs have potential to prevent HBV and EV71 infection simultaneously.

Adjuvants, Immunologic ; Animals ; Antibodies, Neutralizing ; Antibodies, Viral ; blood ; Enterovirus A, Human ; genetics ; Enterovirus Infections ; immunology ; virology ; Epitopes ; immunology ; metabolism ; Escherichia coli ; metabolism ; Female ; Immunity, Cellular ; Immunity, Humoral ; Mice ; Recombinant Fusion Proteins ; immunology

Metastasis is the leading cause of death in breast cancer patients. However, the mechanisms underlying metastasis are not well understood and there is no effective treatment in the clinic. Here, we demonstrate that in MMTV-PyMT, a highly malignant spontaneous breast tumor model, IL-25 (also called IL-17E) was expressed by tumor-infiltrating CD4 T cells and macrophages. An IL-25 neutralization antibody, while not affecting primary tumor growth, substantially reduced lung metastasis. Inhibition of IL-25 resulted in decreased type 2 T cells and macrophages in the primary tumor microenvironments, both reported to enhance breast tumor invasion and subsequent metastasis to the lung. Taken together, our data suggest IL-25 blockade as a novel treatment for metastatic breast tumor.
Animals ; Antibodies, Neoplasm ; pharmacology ; Antibodies, Neutralizing ; pharmacology ; Breast Neoplasms ; drug therapy ; genetics ; immunology ; CD4-Positive T-Lymphocytes ; immunology ; pathology ; Female ; Humans ; Interleukin-17 ; antagonists & inhibitors ; genetics ; immunology ; Interleukins ; antagonists & inhibitors ; genetics ; immunology ; Macrophages ; immunology ; pathology ; Mammary Neoplasms, Animal ; drug therapy ; genetics ; immunology ; Mice ; Neoplasm Metastasis ; Tumor Microenvironment ; drug effects ; genetics ; immunology

Although it is well known that pneumococcal conjugate vaccines provide cross-protection against some vaccine-related serotypes, these mechanisms are still unclear. This study was performed to investigate the role of cross-protective IgM antibodies against vaccine-related serotypes 6A, 6C, and 19A induced in children aged 12-23 months after immunization with 7-valent pneumococcal conjugate vaccine (PCV7). We obtained serum samples from 18 Korean children aged 12-23 months after a PCV7 booster immunization. The serum IgG and IgM concentrations of serotypes 6B and 19F were measured by enzyme-linked immunosorbent assay (ELISA) in serum. The opsonic indices (OIs) against vaccine serotypes 6B and 19F and vaccine-related serotypes 6A, 6C, and 19A were determined by an opsonophagocytic killing assay (OPA) in IgM-depleted and control serum. Both IgG and IgM antibodies in ELISA and opsonic indices in OPA against serotypes 6B and 19F were demonstrated in the immune serum. IgM depletion decreased the OIs against vaccine serotypes 6B (geometric means of OIs (GMIs) of 3,009 vs. 1,396, 38% reduction) and 19F (1,117 vs. 750, 36% reduction). In addition, IgM depletion markedly decreased the OIs against vaccine-related serotypes 6A (GMIs of 961 vs. 329, 70% reduction), 6C (432 vs. 185, 72% reduction), and 19A (301 vs. 166, 58% reduction). The booster immunization PCV7 induced protective antibodies in the form of both IgG and IgM isotypes. IgM antibodies contributed to eliciting cross-protection against vaccine-related serotypes as well as against vaccine serotypes.
Antibodies, Bacterial/blood ; Antibodies, Neutralizing/blood ; Enzyme-Linked Immunosorbent Assay ; Heptavalent Pneumococcal Conjugate Vaccine/*immunology ; Humans ; Immunoglobulin M/*blood ; Infant ; Pneumococcal Infections/*prevention & control ; Pneumococcal Vaccines/*immunology ; Serogroup ; Streptococcus pneumoniae/immunology

Objective To develop neutralizing monoclonal antibodies (MAbs) against H10N8 avian influenza virus hemagglutinin and to identify the binding sites. Methods MAbs against hemagglutinin of H10N8 avian influenza virus were developed by genetic engineering. Neutralizing MAbs were screened by microneutralization assay,and then tested by enzyme-linked immunosorbent assay and Western blot to identity the binding sites.The homology modeling process was performed using Discovery Studio 3.5 software,while the binding epitopes were analyzed by BioEdit software. Results One MAb that could neutralize the H10N8 pseudovirus was obtained and characterized. Analysis about epitopes suggested that the antibody could bind to the HA1 region of hemagglutinin,while the epitopes on antigen were conserved in H10 subtypes.Conclusions One neutralizing antibody was obtained by this research.The MAb may potentially be further developed as a pre-clinical candidate to treat avian influenza H10N8 virus infection.
Antibodies, Monoclonal ; immunology ; Antibodies, Neutralizing ; immunology ; Antibodies, Viral ; immunology ; Enzyme-Linked Immunosorbent Assay ; Epitopes ; immunology ; Hemagglutinin Glycoproteins, Influenza Virus ; immunology ; Influenza A Virus, H10N8 Subtype ; Neutralization Tests