Biology subjects

Pinter, A.

Publications and source records attributed to Pinter, A..

5 recordsLinked to original sources

bioRxiv2023

Broad-Spectrum Heavily Mutated Monoclonal Antibody Isolated from COVID-19 Convalescent Vaccinee with Capacity to Neutralize SARS-CoV2 Variants Ranging from B.1 to BQ.1.1

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=103 SRC="FIGDIR/small/539267v1_ufig1.gif" ALT="Figure 1"> View larger version (45K): org.highwire.dtl.DTLVardef@f7dab8org.highwire.dtl.DTLVardef@388861org.highwire.dtl.DTLVardef@181a7c7org.highwire.dtl.DTLVardef@12e02cb_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG In briefChoudhary et al. have isolated and characterized Acovimab, a broadly neutralizing RBM-specific human monoclonal antibody with a relatively high level of somatic hypermutation, which potently neutralizes SARS-CoV2 variants ranging from WuhanB.1 to OmicronBQ.1.1, but not the XBB.1.5 variant. Acovimab also possesses strong synergistic neutralizing activity against some Omicron variants when combined with Sotrovimab. Polyclonal plasma antibodies from COVID-19 vaccinees who had recovered from SARS-CoV2 infection were shown to possess low neutralizing titers of antibodies against conserved RBD targets of CoV2 variants including XBB.1.5, which also synergistically neutralize with Sotrovimab against this variant. SummaryThe increasing prevalence of the highly antibody-evasive Omicron sublineages increases the risk of breakthrough infections and leaves high-risk and vulnerable immunocompromised individuals with no effective options for prophylactic or therapeutic antibody treatments. Here, we report a heavily mutated anti-RBD monoclonal antibody, Acovimab, directed against a site in the receptor-binding motif (RBM) region of the CoV2 receptor-binding domain (RBD), that possesses very broad and highly potent neutralizing activity against CoV2 variants, including many Omicron variants. This antibody is derived from the IGHV1-58*01 germline sequence and possesses a relatively high level of mutation (15.5% of the VH aa sequence), which is unusual for anti-RBD antibodies. Neutralizing activity was very potent (IC50s range of 1-9 ng/ml) for early Omicron subvariants that possess an unmutated F486 residue and is retained but less potent (IC50s of 200-650 ng/ml) for more resistant Omicron subvariants which contain the F486V mutation (BA4/5, BA4.6, and BQ1.1), but is lost for the later ultra-resistant variants that contain F486S (XBB) or F486P (XBB.1.5) mutations. Based on these specificities, it is predicted that Acovimab by itself should protect against CoV2 infections other than those caused by the XBB/XBB.1.5 family. Acovimab also shows strong synergy in neutralization when combined with Sotrovimab, which neutralizes all Omicron variants, including XBB.1.5. Plasma from subjects with hybrid immunity (induced by vaccination + infection) possessed low levels of XBB.1.5 RBM-targeting plasma-neutralizing antibodies, and these also neutralized synergistically when combined with Sotrovimab. These results suggest potentially novel immunotherapeutic options for treating most of the CoV2 variants responsible for current infections.

immunology↗

bioRxiv2022

Performance of novel antibodies for lipoarabinomannan to develop diagnostic tests for Mycobacterium tuberculosis

Lipoarabinomannan (LAM), a component of the Mycobacterium tuberculosis (MTB) cell wall, is detectable in the urine of MTB infected patients with active tuberculosis (TB). LAM-specific antibodies (Igs) have been developed by a variety of traditional and recombinant methods for potential use in a rapid diagnostic test (RDT). We evaluated the analytical performance of the TB LAM Igs to identify pairs that offer superior performance over existing urine LAM tests. We assessed 25 new and 4 existing Igs in a matrixed format using a multiplex electrochemiluminescence-based liquid immunoassay. A total of 841 paired Ig combinations were challenged with in vitro cultured LAM (cLAM) derived from MTB strains representing diverse phylogenetic lineages, alongside urinary LAM (uLAM) from the urine of adults with active pulmonary TB. Analytical sensitivity of down-selected Ig pairs was determined using MTB Aoyama-B cLAM, while diagnostic accuracy was determined using clinical samples. When testing cLAM, the reactivity of Ig pairs was similar across MTB lineages 1-4 but lineage 5:6 had significantly more reactivity among Ig pairs. Overall, 41 Ig pairs had a strong binding affinity to cLAM, as compared to the reference pair of S4-20/A194-01, and 28 Ig pairs therein exhibited a strong affinity for both cLAM and uLAM. Retrospective testing on clinical urine specimens demonstrated varying sensitivities (12-80%) and specificities (14-100%). The five top pairs had a similar analytical limit of detection to the reference pair but in four instances, the sensitivity and specificity with clinical uLAM samples was poor. Overall, epitopes presented by uLAM are different from cLAM, which may affect antibody performance when testing uLAM in patient samples. Several new Ig pairs had similar ranges of high sensitivity to cLAM but overall, there were no new candidate Ig pairs identified in this round of screening with increased performance with uLAM as compared to an existing optimal pair.

microbiology↗

bioRxiv2021

Robust IgM responses following vaccination are associated with prevention of Mycobacterium tuberculosis infection in macaques

Development of an effective tuberculosis (TB) vaccine has suffered from an incomplete understanding of the correlates of protection against Mycobacterium tuberculosis (Mtb). However, recent work has shown that compared to standard intradermal Bacille Calmette-Guerin (BCG) vaccination, intravenous (IV) BCG vaccination provides nearly complete protection against TB in rhesus macaques. While studies have focused on cellular immunity in this setting, the antibody response elicited by IV BCG vaccination remains incompletely defined. Using an agnostic antibody profiling approach, here we show that IV BCG drives superior antibody responses in the plasma and the bronchoalveolar lavage fluid (BAL). While IV BCG immunization resulted in the expansion of a robust IgM, IgG, IgA, Fc-receptor binding antibodies, and antibody effector functions in the BAL, IgM titers were among the strongest markers of reduced bacterial burden in the plasma and BAL of BCG immunized animals. Moreover, IgM immunity was also enriched among animals receiving protective vaccination with an attenuated Mtb strain. Finally, a LAM-specific IgM monoclonal antibody reduced Mtb survival in vitro. Collectively, these data highlight the potential importance of IgM responses as a marker and as a functional mediator of protection against TB.

immunology↗

bioRxiv2021

Isolation and Purification of Lipoarabinomannan from Urine of Adults with Active Tuberculosis

Lipoarabinomannan (LAM) is a cell wall component of Mycobacterium tuberculosis that is excreted in the urine of persons with active tuberculosis (TB). Limited diagnostic sensitivity of LAM immunoassays has been due to selecting antibodies against LAM derived from in vitro cultured M. tuberculosis, rather than LAM purified from in vivo clinical urine specimens. Urinary LAM (uLAM) is critical to enable the development of and/or screening of novel uLAM-specific antibodies but is typically dilute and in heterogeneous mixtures with other urine components. We used physical, enzymatic, and chemical processes for the scaled isolation and purification of uLAM. The purified material may then be used to develop more sensitive uLAM diagnostic tests for active TB disease.

microbiology↗

bioRxiv2021

CAR-NK Cells Effectively Target the D614 and G614 SARS-CoV-2-infected Cells

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is highly contagious presenting a significant public health issue. Current therapies used to treat coronavirus disease 2019 (COVID-19) include monoclonal antibody cocktail, convalescent plasma, antivirals, immunomodulators, and anticoagulants, though the current therapeutic options remain limited and expensive. The vaccines from Pfizer and Moderna have recently been authorized for emergency use, which are invaluable for the prevention of SARS-CoV-2 infection. However, their long-term side effects are not yet to be documented, and populations with immunocompromised conditions (e.g., organ-transplantation and immunodeficient patients) may not be able to mount an effective immune response. In addition, there are concerns that wide-scale immunity to SARS-CoV-2 may introduce immune pressure that could select for escape mutants to the existing vaccines and monoclonal antibody therapies. Emerging evidence has shown that chimeric antigen receptor (CAR)- natural killer (NK) immunotherapy has potent antitumor response in hematologic cancers with minimal adverse effects in recent studies, however, the potentials of CAR-NK cells in preventing and treating severe cases of COVID-19 has not yet been fully exploited. Here, we improve upon a novel approach for the generation of CAR-NK cells for targeting SARS-CoV-2 and its D614G mutant. CAR-NK cells were generated using the scFv domain of S309 (henceforward, S309-CAR-NK), a SARS-CoV and SARS-CoV-2 neutralizing antibody that targets the highly conserved region of SARS-CoV-2 spike (S) glycoprotein, therefore would be more likely to recognize different variants of SARS-CoV-2 isolates. S309-CAR-NK cells can specifically bind to pseudotyped SARS-CoV-2 virus and its D614G mutant. Furthermore, S309-CAR-NK cells can specifically kill target cells expressing SARS-CoV-2 S protein in vitro and show superior killing activity and cytokine production, compared to that of the recently published CR3022-CAR-NK cells. Thus, these results pave the way for generating off-the-shelf S309-CAR-NK cells for treatment in high-risk individuals as well as provide an alternative strategy for patients unresponsive to current vaccines.

immunology↗