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Antibody

About: Antibody is a research topic. Over the lifetime, 113941 publications have been published within this topic receiving 4130181 citations. The topic is also known as: Ab & antibodies.


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Journal Article
TL;DR: Findings show that a rabbit cell surface component can activate the alternate pathway of complement in human serum and suggest that this activation does not involve antibody.
Abstract: The hemolysis of sheep red blood cells (SRBC) occurs via the classical complement pathway and is blocked by ethylene glycol bis-amino tetraacetate (EGTA). By contrast, fresh normal human serum in EGTA buffer was found to cause >90% hemolysis of unsensitized rabbit red blood cells (RaRBC) at a final dilution of 1:15. Absorbing human serum with RaRBC at 0°C will remove only 45% of this hemolytic activity and the same activity is present in human hypogammaglobulinemic serum. When rabbit lymphocytes were incubated with human serum in EGTA buffer, complement fixation occurred on their surface which was demonstrated with radiolabeled antibodies to human C3 or as “blocking” of the complement receptor. With purified complement components it was shown that the EGTA buffer completely blocked C1 but not C4, C2, or the late complement components. These findings show that a rabbit cell surface component can activate the alternate pathway of complement in human serum and suggest that this activation does not involve antibody.

457 citations

Journal ArticleDOI
28 Oct 1988-Science
TL;DR: It is suggested that this immunological response to HIV-1, instead of protecting the host, potentially facilitates the infection and is compatible with the concept of FcR-mediated infection enhancement.
Abstract: Monocytes and macrophages, which may play a central role in the pathogenesis of infection with human immunodeficiency virus type 1 (HIV-1), express the CD4 molecule and Fc receptors (FcR) for immunoglobulin G (IgG). To explore the possibility that FcR mediate HIV-1 infection of monocytes, studies were conducted with the human monocytic cell line U937. These cells were exposed to HIV-1 complexed with various concentrations of serum from HIV-1 antibody-positive individuals and monitored for HIV-1 replication. Serum samples from antibody-negative normal individuals did not affect virus yields. High concentrations of antibody-positive sera showed virus-neutralizing activity; however, cells infected with HIV-1 in the presence of antibody-positive sera at subneutralizing concentrations significantly enhanced virus replication. This infection enhancement was blocked by heat-aggregated gamma-globulin. Moreover, the IgG fraction from an HIV-1 antibody-positive serum enhanced HIV-1 infection at the same serum dilution equivalents. In contrast, IgG-F(ab')2 did not enhance HIV-1 infection but showed neutralizing activity with HIV-1. These results are compatible with the concept of FcR-mediated infection enhancement and suggest that this immunological response to HIV-1, instead of protecting the host, potentially facilitates the infection.

457 citations

Journal ArticleDOI
TL;DR: An artificial intelligence model, which has been trained with tens of thousands of experimental data and extensively validated by experimental results on SARS-CoV-2, reveals that Omicron may be over 10 times more contagious than the original virus or about 2.8 times as infectious as the Delta variant.
Abstract: The latest severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant Omicron (B.1.1.529) has ushered panic responses around the world due to its contagious and vaccine escape mutations. The essential infectivity and antibody resistance of the SARS-CoV-2 variant are determined by its mutations on the spike (S) protein receptor-binding domain (RBD). However, a complete experimental evaluation of Omicron might take weeks or even months. Here, we present a comprehensive quantitative analysis of Omicron’s infectivity, vaccine breakthrough, and antibody resistance. An artificial intelligence (AI) model, which has been trained with tens of thousands of experimental data and extensively validated by experimental results on SARS-CoV-2, reveals that Omicron may be over 10 times more contagious than the original virus or about 2.8 times as infectious as the Delta variant. On the basis of 185 three-dimensional (3D) structures of antibody–RBD complexes, we unveil that Omicron may have an 88% likelihood to escape current vaccines. The U.S. Food and Drug Administration (FDA)-approved monoclonal antibodies (mAbs) from Eli Lilly may be seriously compromised. Omicron may also diminish the efficacy of mAbs from AstraZeneca, Regeneron mAb cocktail, Celltrion, and Rockefeller University. However, its impacts on GlaxoSmithKline’s sotrovimab appear to be mild. Our work calls for new strategies to develop the next generation mutation-proof SARS-CoV-2 vaccines and antibodies.

457 citations

Journal ArticleDOI
TL;DR: Four monoclonal anti-DNA antibodies derived from a single autoimmune MRL/lpr mouse were studied and complete nucleotide sequences of heavy- and light-chain variable regions demonstrated that all four antibodies are clonally related.
Abstract: Four monoclonal anti-DNA antibodies derived from a single autoimmune MRL/lpr mouse were studied. Three of these antibodies showed similarities in DNA binding; the fourth had a much higher specific activity for single-stranded DNA and, in addition, was unique in binding double-stranded DNA and cardiolipin. Complete nucleotide sequences of heavy- and light-chain variable regions demonstrated that all four antibodies are clonally related. The sequences also showed numerous somatic mutations, the distribution of which suggests that positive selection by antigen operated on these clonally related autoantibodies.

457 citations

Journal ArticleDOI
TL;DR: It is demonstrated that 1,25-(OH)2-D3 is a potent inhibitor of human PBM Ig production in vitro and suggested that this action is mediated through the hormone's antiproliferative effect on Ig-producing B cells and/or helper T cells.
Abstract: Activated B and T lymphocytes from normal human subjects are known to have the specific high-affinity receptor for 1,25-dihydroxyvitamin D3 (1,25-(OH)2-D3). In an attempt to determine a functional role for the sterol in such cells, we studied the effect of 1,25-(OH)2-D3 on DNA synthesis and Ig production by normal human peripheral blood mononuclear (PBM) cells activated in vitro by the polyclonal lymphocyte activators pokeweed mitogen and phytohemagglutinin, and the specific antigen dermatophyton O. A dose-dependent inhibition of [3H]thymidine incorporation was observed in cells incubated with 1,25-(OH)2-D3 in concentrations ranging from 10(-10) to 10(-7) M. Production of IgG and IgM, determined by enzyme-linked immunosorbent assay, was similarly inhibited by increasing concentrations of 1,25-(OH)2-D3. Half-maximal inhibition of DNA and Ig synthesis was found at 10(-10) to 10(-9) M 1,25-(OH)2-D3. This suppressive effect was specific for 1,25-(OH)2-D3; of the other vitamin D metabolites examined, only 10(-7) M 24R,25 dihydroxyvitamin D3 (24,25-(OH)2-D3) had a similar inhibitory effect. 1,25-(OH)2-D3 was not cytotoxic and did not affect unactivated PBMs. These data demonstrate that 1,25-(OH)2-D3 is a potent inhibitor of human PBM Ig production in vitro and suggest that this action is mediated through the hormone's antiproliferative effect on Ig-producing B cells and/or helper T cells.

456 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20243
20238,687
202213,454
20213,167
20203,126
20192,578