scholarly journals 1008. Presence of Antibody Dependent Cell Cytotoxicity (ADCC) Functional Antibodies that Target a Complex Gp41 Epitope Correlates with Long-term Non-progression and ADCC is Maintained with Mutants Using Germline Heavy Chain Variable Gene Sequence of VH1-02 Gene

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S594-S595
Author(s):  
Sarah Baron ◽  
Meghan Garrett ◽  
Mark D Hicar
Keyword(s):  
Heavy Chain ◽  
Light Chain ◽  
Gene Sequence ◽  
Common Ancestor ◽  
Conformational Epitope ◽  
Cell Cytotoxicity ◽  
Clade B ◽  
Dependent Cell ◽  
Variable Gene

Abstract Background Recent data supports that improved qualitative antibody responses correlate with elite controllers (EC) of HIV. As ADCC has been associated with protection in vaccine studies, thorough exploration of antibodies that facilitate ADCC is warranted. In studies on monoclonal antibodies from long-term non-progressors (LTNPs), our laboratory has previously described highly mutated antibodies against a complex conformational epitope with contributions from both gp41 heptad repeat regions. Despite using the VH1-02 gene segment, known to contribute to some of the broadest neutralizing antibodies against HIV, members of these antibodies, termed group 76C antibodies, did not exhibit broad neutralization. Methods Our goal was to characterize the non-neutralizing functions of antibodies of group 76C, to assess targeting of the epitope in various clinical presentations, and to assess the development of these antibodies by comparison to their predicted common ancestor. Serum samples were obtained from HIV+ clinical groups: EC, LTNP, stable CD4 counts on therapy, and those off therapy. Results In antibody/serum competition assays, comparison to VRC01 which also uses VH1-02, showed that antibodies targeting the 76C group epitope were enriched in LTNPs. We then show recombinant antibodies of 76C members 6F5 and 6F11 both have robust ADCC activity, despite their sequence disparity. Sequence analysis predicted the common ancestor of this clonal group would utilize the germline non-mutated variable gene. We produced a recombinant ancestor Ab (76Canc) with a heavy chain utilizing the germline variable gene sequence paired to the 6F5 light chain. 76Canc binds HIV envelope constructs near the original group C epitope. 76Canc also shows comparable ADCC to 6F5 and 6F11 on both clade B and C constructs. Common ancestor antibodies maintain function and these types of antibodies correlate to a non-progressive clinical state. (A) Serum from long-term non-progressors (LTNPs) compared to serum from a group of HIV infected with lower CD4 levels as a control for viral load were used to compete against biotinylated CD4 binding site (VRC01) and 76C Gp41 conformational epitope (6F11) targeting antibodies. Serum dilutions were chosen to align means near 50%. Means with 95% confidence intervals are shown. (B) Monoclonal antibody 76Canc was created using the germline sequence of the heavy chain variable region with the CDR3 and light chain of 76C member. Antibody dependent cell cytotoxicity flow cytometric based assays were performed using gp41 proteins from clade B (MN) and clade C (ZA1197). Conclusion Certain antibodies present early on in infection may contribute to overall clinical course. Variable gene germline sequences that support functional activity against HIV could be targeted in vaccine regimens. Disclosures All Authors: No reported disclosures

scholarly journals The unmutated common ancestor of Gp41 conformational epitope targeting variable heavy chain 1-02 utilizing antibodies maintains antibody dependent cell cytotoxicity

2021 ◽  
Author(s):  
Brian Wrotniak ◽  
Meghan E Garrett ◽  
Sarah Baron ◽  
Hakimuddin Sojar ◽  
Alyssa Shon ◽  
...  
Keyword(s):  
Heavy Chain ◽  
Common Ancestor ◽  
Vaccine Development ◽  
Gene Segment ◽  
Conformational Epitope ◽  
Heptad Repeat ◽  
Clade B ◽  
Variable Heavy ◽  
Dependent Cell ◽  
Variable Gene

In studies on monoclonal Abs (mAbs) from long-term non-progressors (LTNPs), our laboratory has previously described highly mutated Abs against a complex conformational epitope with contributions from both gp41 heptad repeat regions. Despite using the VH1-02 gene segment, known to contribute to some of the broadest neutralizing Abs against HIV, members of these Abs, termed group 76C Abs, did not exhibit broad neutralization.<br />Because of the excessive mutations and use of VH1-02, our goal was to characterize the non-neutralizing functions of Abs of group 76C, to assess targeting of the epitope in various clinical presentations, and to assess the development of these Abs by comparison to their predicted common ancestor. Serum competition assays showed group 76C Abs were enriched in LTNPs, in comparison to VRC-01. Specific group 76C clones 6F5 and 6F11, expressed as recombinant Abs, both have robust ADCC activity, despite their sequence disparity. Sequence analysis predicted the common ancestor of this clonal group would utilize the germline non-mutated variable gene. We produced a recombinant ancestor Ab (76Canc) with a heavy chain utilizing the germline variable gene sequence paired to the 6F5 light chain. Competition with group 76C recombinant Ab 6F5 confirms 76Canc binds HIV envelope constructs near the original group C epitope. 76Canc demonstrates comparable ADCC to 6F5 and 6F11 when targeting both clade B and C HIV constructs. The functional capability of Abs utilizing germline VH1-02 has implications for disease control and vaccine development.

scholarly journals Genetic elements used for a murine lupus anti-DNA autoantibody are closely related to those for antibodies to exogenous antigens.

1985 ◽  
Vol 161 (4) ◽  
pp. 805-815 ◽  
Author(s):  
R Kofler ◽  
D J Noonan ◽  
D E Levy ◽  
M C Wilson ◽  
N P Møller ◽  
...  
Keyword(s):  
Heavy Chain ◽  
Light Chain ◽  
Variable Region ◽  
Leader Peptide ◽  
Murine Lupus ◽  
Heavy Chain Variable Region ◽  
Variable Gene ◽  
Vh Gene ◽  
Gene Origin ◽  
Common Variable

The mRNAs encoding heavy and light chains of a hybridoma-derived monoclonal IgM kappa anti-DNA autoantibody from lupus-prone MRL/Mp-lpr/lpr mice (Ighj) have been transcribed into cDNA copies and molecularly cloned, and their complete nucleotide sequences have been determined. The mRNA for the heavy chain variable region, including leader peptide and 5' untranslated region, is transcribed from a heavy chain variable region (VH) gene closely related (and possibly allelic) to VH genes of the C57BL/6 (Ighb) nitrophenyl antibody family. The deduced amino acid sequence corresponding to the light chain variable region of this autoantibody shows extensive similarities with non-autoantibody molecules of the V kappa 1 group, suggesting a common variable gene origin. The joining segments, constant regions, and 3' untranslated regions of both the heavy and light chain mRNAs are nearly identical to corresponding sequences of non-autoantibodies from normal mice. Our findings suggest that this anti-DNA autoantibody originated from the same germline repertoire as antibodies to exogenous antigens.

scholarly journals Monoclonal Antibody 2C6 Targets a Cross-Clade Conformational Epitope in gp41 with Highly Active Antibody-Dependent Cell Cytotoxicity

2019 ◽  
Vol 93 (17) ◽  
Author(s):  
Hakimuddin Sojar ◽  
Sarah Baron ◽  
Jonathan T. Sullivan ◽  
Meghan Garrett ◽  
Marlies M. van Haaren ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibody ◽  
Amino Acid ◽  
Envelope Protein ◽  
Conformational Epitope ◽  
Cell Cytotoxicity ◽  
Alanine Scanning Mutagenesis ◽  
Dependent Cell ◽  
Amino Acid Mutations ◽  
Trimeric Envelope

ABSTRACTPrevious studies in our laboratory characterized a panel of highly mutated HIV-specific conformational epitope-targeting antibodies (Abs) from a panel of HIV-infected long-term nonprogressors (LTNPs). Despite binding HIV envelope protein and having a high number of somatic amino acid mutations, these Abs had poor neutralizing activity. Because of the evidence of antigen-driven selection and the long CDR3 region (21 amino acids [aa]), we further characterized the epitope targeting of monoclonal Ab (MAb) 76-Q3-2C6 (2C6). We confirmed that 2C6 binds preferentially to trimeric envelope and recognizes the clades A, B, and C SOSIP trimers. 2C6 binds gp140 constructs of clades A, B, C, and D, suggesting a conserved binding site that we localized to the ectodomain of gp41. Ab competition with MAb 50-69 suggested this epitope localizes near aa 579 to 613 (referenced to HXB2 gp160). Peptide library scanning showed consistent binding in this region but to only a single peptide. Lack of overlapping peptide binding supported a nonlinear epitope structure. The significance of this site is supported by 2C6 having Ab-dependent cell cytotoxicity (ADCC) against envelope proteins from two clades. Using 2C6 and variants, alanine scanning mutagenesis identified three amino acids (aa 592, 595, and 596) in the overlapping region of the previously identified peptide. Additional amino acids at sites 524 and 579 were also identified, helping explain its conformational requirement. The fact that different amino acids were included in the epitope depending on the targeted protein supports the conclusion that 2C6 targets a native conformational epitope. When we mapped these amino acids on the trimerized structure, they spanned across oligomers, supporting the notion that the epitope targeted by 2C6 lies in a recessed pocket between two gp41 oligomers. A complete understanding of the epitope specificity of ADCC-mediating Abs is essential for developing effective immunization strategies that optimize protection by these Abs.IMPORTANCEThis paper further defines the function and area of the HIV trimeric envelope protein targeted by the monoclonal antibody 2C6. 2C6 binding is influenced by amino acid mutations across two separate gp41 sections of the envelope trimer. This epitope is recognized on multiple clades (variant groups of circulating viruses) of gp41, gp140 trimers, and SOSIP trimers. For the clades tested, 2C6 has robust ADCC. As the target of 2C6 is available in the major clades of HIV and has robust ADCC activity, further definition and appreciation of targeting of antibodies similar to 2C6 during vaccine development should be considered.

scholarly journals The immunoglobulin heavy chain variable gene segment 4-31, IGHV 4-31, is differentially expressed in the brain and lymph nodes of patients with metastatic breast cancer.

2020 ◽  
Author(s):  
Shahan Mamoor
Keyword(s):  
Breast Cancer ◽  
Metastatic Breast Cancer ◽  
Brain Metastases ◽  
Heavy Chain ◽  
Light Chain ◽  
Gene Segment ◽  
Metastatic Breast ◽  
Variable Gene ◽  
The Brain ◽  
Variable Gene Segment

One study reported the incidence of central nervous system metastases in breast cancer patients treated with trastuzumab as 34% (1). We mined published microarray data (2-4) to discover genes associated with brain metastasis in breast cancer. We identified significant differential expression of the immunoglobulin heavy chain variable gene segment IGHV 4-31 in the metastases of patients with metastatic breast cancer, both in the lymph nodes and in the brain. We recently described the differential expression of the immunoglobulin light chain kappa constant locus in the brain metastases of patients with metastatic breast cancer (5). These data suggest both heavy and light chain gene segments may potentially be among the loci whose expression is most significantly altered transcriptome-wide when comparing primary tumors of the breast and brain metastases in patients with metastatic breast cancer. IGHV 4-31 may be relevant to the biology underlying colonization of the brain with metastatic breast cancer clones.

LIPOPOLYSACCHARIDE-SENSITIVE SERINE-PROTEASE ZYMOGEN (FACTOR C) OF LIMULUS HEMOCYTES: IDENTIFICATION AND ALIGNMENT OF PROTEOLYTIC FRAGMENTS PRODUCED DURING THE ACTIVATION SHOW THAT IT IS A NOVEL TYPE OF SERINE-PROTEASE

1987 ◽  
Author(s):  
F Tokunaga ◽  
T Miyata ◽  
T Nakamura ◽  
T Morita ◽  
S Iwanaga
Keyword(s):  
Serine Protease ◽  
Heavy Chain ◽  
Light Chain ◽  
Interleukin 2 ◽  
Coagulation Factor ◽  
Clotting Factor ◽  
Single Chain ◽  
Terminal Sequence ◽  
A Chain ◽  
Factor C

Limulus clotting factor, factor C, is a lipopolysaccharide (LPS)-sensitive serine-protease zymogen present in the hemocytes. It is a two-chain glycoprotein (M.W. = 123,000) composed of a heavy chain (M.W. = 80,000) and a light chain (M.W. = 43,000) T. Nakamura et al. (1986) Eur. J. Biochem. 154, 511-521 .On further studies of this zymogen, a single-chain factor C (M.W. = 123,000) was identified by Western blotting technique. The heavy chain had an NH2-terminal sequence of Ser-Gly-Val-Asp-, which was consistent with the NH2-terminal sequence of the single-chain factor C, indicating that the heavy chain is located in the NH2-terminal part of the zymogen. The light chain had an NH22-terminal sequence of Ser-Ser-Gln-Pro-. Incubation of the two-chain zymogen with LPS resulted in the cleavage of a Phe-Ile bond between residues 72 and 73 of the light chain. Concomitant with this cleavage, the A (72.amino acids) and B chains derived from the light chain was formed. The complete amino acid sequence of the A chain was determined by automated Edman degradation. The A chain contained a typical segment which is similar structuraly to those a family of repeats in human β2 -glycoprotein I, complement factors B, Clr, Cls, H, C4b-binding protein, 02, coagulation factor XIII b subunit, haptoglobin a chain, and interleukin 2 receptor. The NH2-terminal sequence of the B chain was Ile-Trp-Asn-Gly-. This chain contained the serine-active site sequence of -ASP-Ala-Cys-Ser-Gly-Asp-SER-Gly-Gly-Pro-.These results indicate that limulus factor C exists in the hemocytes in a single-chain zymogen form and is converted to an active serine-protease by hydrolysis of a specific Phe-Ile peptide bond. The correlation of limulus factor C and mammalian complement proteins was also suggested.

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