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  1. Article ; Online: Assessments of HLA-I Specificities of Anti-HLA-I Monoclonal Antibodies Using Solid Phase Bead Arrays.

    Zaitouna, Anita J / Ramon, Daniel S / Raghavan, Malini

    Bio-protocol

    2020  Volume 10, Issue 12, Page(s) e3655

    Abstract: Human leukocyte antigen class I (HLA-I) molecules are a group of structurally-related cell surface proteins with a high degree of variability within the population. While only up to six variants are expressed in an individual person, the whole population ...

    Abstract Human leukocyte antigen class I (HLA-I) molecules are a group of structurally-related cell surface proteins with a high degree of variability within the population. While only up to six variants are expressed in an individual person, the whole population contains thousands of different variants. The ability to distinguish specific variants is important in the clinic to determine compatibility during organ and bone marrow transplantation and in the laboratory to study the biological properties of individual variants. Solid phase bead arrays contain purified, individually identifiable HLA-I molecules that can be used to determine antibody specificity for individual HLA-I proteins. This method is high-throughput, highly specific, and allows for simultaneous screening of antibodies against multiple HLA-I allotypes. The beads are particularly useful for screening patient sera for the presence of donor-specific antibodies against individual HLA-I variants (which can arise during pregnancy, blood transfusion, or organ transplantation). Alternate approaches, such as the use of individual HLA-I-expressing cell lines, are more time consuming, and such cell lines are difficult to procure and standardize. The HLA-I beads are also useful to study HLA-I specificity and selectivity for other receptors and binding partners.
    Language English
    Publishing date 2020-06-20
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2833269-6
    ISSN 2331-8325 ; 2331-8325
    ISSN (online) 2331-8325
    ISSN 2331-8325
    DOI 10.21769/BioProtoc.3655
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: (with research data) Selected HLA-B allotypes are resistant to inhibition or deficiency of the transporter associated with antigen processing (TAP).

    Geng, Jie / Zaitouna, Anita J / Raghavan, Malini

    PLoS pathogens

    2018  Volume 14, Issue 7, Page(s) e1007171

    Abstract: Major histocompatibility complex class I (MHC-I) molecules present antigenic peptides to CD8+ T cells, and are also important for natural killer (NK) cell immune surveillance against infections and cancers. MHC-I molecules are assembled via a complex ... ...

    Abstract Major histocompatibility complex class I (MHC-I) molecules present antigenic peptides to CD8+ T cells, and are also important for natural killer (NK) cell immune surveillance against infections and cancers. MHC-I molecules are assembled via a complex assembly pathway in the endoplasmic reticulum (ER) of cells. Peptides present in the cytosol of cells are transported into the ER via the transporter associated with antigen processing (TAP). In the ER, peptides are assembled with MHC-I molecules via the peptide-loading complex (PLC). Components of the MHC-I assembly pathway are frequently targeted by viruses, in order to evade host immunity. Many viruses encode inhibitors of TAP, which is thought to be a central source of peptides for the assembly of MHC-I molecules. However, human MHC-I (HLA-I) genes are highly polymorphic, and it is conceivable that several variants can acquire peptides via TAP-independent pathways, thereby conferring resistance to pathogen-derived inhibitors of TAP. To broadly assess TAP-independent expression within the HLA-B locus, expression levels of 27 frequent HLA-B alleles were tested in cells with deficiencies in TAP. Approximately 15% of tested HLA-B allotypes are expressed at relatively high levels on the surface of TAP1 or TAP2-deficient cells and occur in partially peptide-receptive forms and Endoglycosidase H sensitive forms on the cell surface. Synergy between high peptide loading efficiency, broad specificity for peptides prevalent within unconventional sources and high intrinsic stability of the empty form allows for deviations from the conventional HLA-I assembly pathway for some HLA-B*35, HLA-B*57 and HLA-B*15 alleles. Allotypes that display higher expression in TAP-deficient cells are more resistant to viral TAP inhibitor-induced HLA-I down-modulation, and HLA-I down-modulation-induced NK cell activation. Conversely, the same allotypes are expected to mediate stronger CD8+ T cell responses under TAP-inhibited conditions. Thus, the degree of resistance to TAP inhibition functionally separates specific HLA-B allotypes.
    MeSH term(s) ATP-Binding Cassette Transporters/metabolism ; HLA-B Antigens/genetics ; HLA-B Antigens/immunology ; Humans ; Immune Evasion/immunology ; Immunologic Surveillance/immunology
    Chemical Substances ATP-Binding Cassette Transporters ; HLA-B Antigens ; transporter associated with antigen processing (TAP)
    Language English
    Publishing date 2018-07-11
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2205412-1
    ISSN 1553-7374 ; 1553-7366
    ISSN (online) 1553-7374
    ISSN 1553-7366
    DOI 10.1371/journal.ppat.1007171
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: An electrochemical peptide-based Ara h 2 antibody sensor fabricated on a nickel(II)-nitriloacetic acid self-assembled monolayer using a His-tagged peptide.

    Zaitouna, Anita J / Lai, Rebecca Y

    Analytica chimica acta

    2014  Volume 828, Page(s) 85–91

    Abstract: We report, for the first time, the use of a Ni(II)-nitriloacetic acid (NTA) self-assembled monolayer (SAM) in the fabrication of an electrochemical peptide-based (E-PB) sensor for detection of anti-Ara h 2 antibodies. We compared the performance of the ... ...

    Abstract We report, for the first time, the use of a Ni(II)-nitriloacetic acid (NTA) self-assembled monolayer (SAM) in the fabrication of an electrochemical peptide-based (E-PB) sensor for detection of anti-Ara h 2 antibodies. We compared the performance of the sensor fabricated on a Ni(II)-NTA SAM using a His-tagged peptide with the sensor fabricated using the conventional approach via direct immobilization of a thiolated peptide. While both sensors responded only to the correct antibody in the presence of random antibodies, we observed differences between the sensors. Specifically, the detection limit of the His-tagged sensor was 1pM, significantly lower than the 200pM detection limit of the conventional thiolated sensor. More importantly, unlike our previously developed E-PB sensors, both sensors are regenerable and reusable. The thiolated sensor can be readily regenerated using guanidine hydrochloride; whereas the His-tagged sensor can be regenerated by direct displacement of the His-tagged probes using Ni(II) ions. Overall, our results show that both approaches are well-suited for E-PB sensor fabrication; more importantly, specific sensor properties such as detection limit and dynamic range can be tuned by simply using a different probe immobilization method.
    MeSH term(s) Antibodies/analysis ; Biosensing Techniques ; Electrochemical Techniques ; Histidine/analysis ; Histidine/chemistry ; Nickel/chemistry ; Nitrilotriacetic Acid/chemistry ; Organometallic Compounds/chemical synthesis ; Organometallic Compounds/chemistry ; Peptides/chemistry
    Chemical Substances Antibodies ; Organometallic Compounds ; Peptides ; Histidine (4QD397987E) ; Nickel (7OV03QG267) ; Nitrilotriacetic Acid (KA90006V9D)
    Language English
    Publishing date 2014-05-30
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1483436-4
    ISSN 1873-4324 ; 0003-2670
    ISSN (online) 1873-4324
    ISSN 0003-2670
    DOI 10.1016/j.aca.2014.04.033
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Mass spectrometric profiling of HLA-B44 peptidomes provides evidence for tapasin-mediated tryptophan editing.

    Kaur, Amanpreet / Surnilla, Avrokin / Zaitouna, Anita J / Basrur, Venkatesha / Mumphrey, Michael B / Grigorova, Irina / Cieslik, Marcin / Carrington, Mary / Nesvizhskii, Alexey I / Raghavan, Malini

    bioRxiv : the preprint server for biology

    2023  

    Abstract: Activation of ... ...

    Abstract Activation of CD8
    Language English
    Publishing date 2023-02-27
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.02.26.530125
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Mass Spectrometric Profiling of HLA-B44 Peptidomes Provides Evidence for Tapasin-Mediated Tryptophan Editing.

    Kaur, Amanpreet / Surnilla, Avrokin / Zaitouna, Anita J / Mumphrey, Michael B / Basrur, Venkatesha / Grigorova, Irina / Cieslik, Marcin / Carrington, Mary / Nesvizhskii, Alexey I / Raghavan, Malini

    Journal of immunology (Baltimore, Md. : 1950)

    2023  Volume 211, Issue 9, Page(s) 1298–1307

    Abstract: The extreme polymorphisms of HLA class I proteins result in structural variations in their peptide binding sites to achieve diversity in Ag presentation. External factors could independently constrict or alter HLA class I peptide repertoires. Such ... ...

    Abstract The extreme polymorphisms of HLA class I proteins result in structural variations in their peptide binding sites to achieve diversity in Ag presentation. External factors could independently constrict or alter HLA class I peptide repertoires. Such effects of the assembly factor tapasin were assessed for HLA-B*44:05 (Y116) and a close variant, HLA-B*44:02 (D116), which have low and high tapasin dependence, respectively, for their cell surface expression. Analyses of the HLA-B*44:05 peptidomes in the presence and absence of tapasin reveal that peptides with C-terminal tryptophans and higher predicted affinities are preferentially selected by tapasin, coincident with reduced frequencies of peptides with other C-terminal amino acids, including leucine. Comparisons of the HLA-B*44:05 and HLA-B*44:02 peptidomes indicate the expected structure-based alterations near the peptide C termini, but also C-terminal amino acid frequency and predicted affinity changes among the unique and shared peptide groups for B*44:02 and B*44:05. Overall, these findings indicate that the presence of tapasin and the tapasin dependence of assembly alter HLA class I peptide-binding preferences at the peptide C terminus. The particular C-terminal amino acid preferences that are altered by tapasin are expected to be determined by the intrinsic peptide-binding specificities of HLA class I allotypes. Additionally, the findings suggest that tapasin deficiency and reduced tapasin dependence expand the permissive affinities of HLA class I-bound peptides, consistent with prior findings that HLA class I allotypes with low tapasin dependence have increased breadth of CD8+ T cell epitope presentation and are more protective in HIV infections.
    MeSH term(s) Humans ; HLA-B44 Antigen/metabolism ; Tryptophan/metabolism ; HIV Infections ; Peptides/metabolism ; Histocompatibility Antigens Class I/genetics ; Histocompatibility Antigens Class I/metabolism ; Immunoglobulins/metabolism ; Protein Binding ; HLA-B Antigens/genetics ; HLA-B Antigens/metabolism
    Chemical Substances tapasin ; HLA-B44 Antigen ; Tryptophan (8DUH1N11BX) ; Peptides ; Histocompatibility Antigens Class I ; Immunoglobulins ; HLA-B Antigens
    Language English
    Publishing date 2023-09-22
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Intramural ; Research Support, N.I.H., Extramural
    ZDB-ID 3056-9
    ISSN 1550-6606 ; 0022-1767 ; 1048-3233 ; 1047-7381
    ISSN (online) 1550-6606
    ISSN 0022-1767 ; 1048-3233 ; 1047-7381
    DOI 10.4049/jimmunol.2300232
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Strategies for the measurements of expression levels and half-lives of HLA class I allotypes.

    Raghavan, Malini / Yarzabek, Brogan / Zaitouna, Anita J / Krishnakumar, Sujatha / Ramon, Daniel S

    Human immunology

    2019  Volume 80, Issue 4, Page(s) 221–227

    Abstract: HLA class I molecules are highly polymorphic cell surface proteins that trigger immune responses by ... ...

    Abstract HLA class I molecules are highly polymorphic cell surface proteins that trigger immune responses by CD8
    MeSH term(s) CD8-Positive T-Lymphocytes/immunology ; Flow Cytometry ; Gene Expression ; Graft Rejection/immunology ; HLA Antigens/genetics ; Half-Life ; Histocompatibility Antigens Class I/genetics ; Histocompatibility Testing/methods ; Humans ; Isoantigens/genetics ; Isoantigens/immunology ; Killer Cells, Natural/immunology ; Organ Transplantation ; Polymorphism, Genetic ; Vaccines
    Chemical Substances HLA Antigens ; Histocompatibility Antigens Class I ; Isoantigens ; Vaccines
    Language English
    Publishing date 2019-02-05
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 801524-7
    ISSN 1879-1166 ; 0198-8859
    ISSN (online) 1879-1166
    ISSN 0198-8859
    DOI 10.1016/j.humimm.2019.02.001
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Methylene blue-mediated electrocatalytic detection of hexavalent chromium.

    Korshoj, Lee E / Zaitouna, Anita J / Lai, Rebecca Y

    Analytical chemistry

    2015  Volume 87, Issue 5, Page(s) 2560–2564

    Abstract: We report, for the first time, the design and fabrication of an electrochemical ion (E-ION) sensor for highly specific detection of hexavalent chromium (Cr(VI)). Unlike previously developed electrochemical Cr(VI) sensors, the sensing mechanism relies on ... ...

    Abstract We report, for the first time, the design and fabrication of an electrochemical ion (E-ION) sensor for highly specific detection of hexavalent chromium (Cr(VI)). Unlike previously developed electrochemical Cr(VI) sensors, the sensing mechanism relies on the previously unexplored electrocatalytic reaction between Cr(VI) and surface-immobilized methylene blue (MB). The sensor is sensitive, specific, and selective enough to be used in a synthetic aquifer sample. Like many sensors of this class, it is also reagentless, reusable, and compatible with gold-plated screen-printed carbon electrodes. Despite the difference in the sensing mechanism, this E-ION Cr(VI) sensor possesses attributes similar to other MB-based electrochemical sensors, sensors with potential for real world applications.
    MeSH term(s) Biosensing Techniques ; Chromium/analysis ; Electrochemical Techniques/methods ; Electrodes ; Gold/chemistry ; Methylene Blue/chemistry
    Chemical Substances Chromium (0R0008Q3JB) ; chromium hexavalent ion (18540-29-9) ; Gold (7440-57-5) ; Methylene Blue (T42P99266K)
    Language English
    Publishing date 2015-03-03
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1508-8
    ISSN 1520-6882 ; 0003-2700
    ISSN (online) 1520-6882
    ISSN 0003-2700
    DOI 10.1021/acs.analchem.5b00197
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Incorporation of extra amino acids in peptide recognition probe to improve specificity and selectivity of an electrochemical peptide-based sensor.

    Zaitouna, Anita J / Maben, Alex J / Lai, Rebecca Y

    Analytica chimica acta

    2015  Volume 886, Page(s) 157–164

    Abstract: We investigated the effect of incorporating extra amino acids (AA) at the n-terminus of the thiolated and methylene blue-modified peptide probe on both specificity and selectivity of an electrochemical peptide-based (E-PB) HIV sensor. The addition of a ... ...

    Abstract We investigated the effect of incorporating extra amino acids (AA) at the n-terminus of the thiolated and methylene blue-modified peptide probe on both specificity and selectivity of an electrochemical peptide-based (E-PB) HIV sensor. The addition of a flexible (SG)3 hexapeptide is, in particular, useful in improving sensor selectivity, whereas the addition of a highly hydrophilic (EK)3 hexapeptide has shown to be effective in enhancing sensor specificity. Overall, both E-PB sensors fabricated using peptide probes with the added AA (SG-EAA and EK-EAA) showed better specificity and selectivity, especially when compared to the sensor fabricated using a peptide probe without the extra AA (EAA). For example, the selectivity factor recorded in the 50% saliva was ∼2.5 for the EAA sensor, whereas the selectivity factor was 7.8 for both the SG-EAA and EK-EAA sensors. Other sensor properties such as the limit of detection and dynamic range were minimally affected by the addition of the six AA sequence. The limit of detection was 0.5 nM for the EAA sensor and 1 nM for both SG-EAA and EK-EAA sensors. The saturation target concentration was ∼200 nM for all three sensors. Unlike previously reported E-PB HIV sensors, the peptide probe functions as both the recognition element and antifouling passivating agent; this modification eliminates the need to include an additional antifouling diluent, which simplifies the sensor design and fabrication protocol.
    MeSH term(s) Amino Acid Sequence ; Amino Acids/chemistry ; Biosensing Techniques/methods ; Electrochemical Techniques/methods ; HIV/isolation & purification ; HIV Infections/diagnosis ; Humans ; Methylene Blue/chemistry ; Molecular Sequence Data ; Peptides/chemistry ; Saliva/virology ; Sulfhydryl Compounds/chemistry ; Urine/virology
    Chemical Substances Amino Acids ; Peptides ; Sulfhydryl Compounds ; Methylene Blue (T42P99266K)
    Language English
    Publishing date 2015-07-30
    Publishing country Netherlands
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1483436-4
    ISSN 1873-4324 ; 0003-2670
    ISSN (online) 1873-4324
    ISSN 0003-2670
    DOI 10.1016/j.aca.2015.05.037
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Design and characterization of a metal ion-imidazole self-assembled monolayer for reversible immobilization of histidine-tagged peptides.

    Zaitouna, Anita J / Lai, Rebecca Y

    Chemical communications (Cambridge, England)

    2011  Volume 47, Issue 45, Page(s) 12391–12393

    Abstract: We report the design and characterization of a metal ion-imidazole self-assembled monolayer on a gold electrode. The resultant monolayer is well-suited for direct immobilization of histidine and methylene blue-modified peptides. ...

    Abstract We report the design and characterization of a metal ion-imidazole self-assembled monolayer on a gold electrode. The resultant monolayer is well-suited for direct immobilization of histidine and methylene blue-modified peptides.
    MeSH term(s) Electrochemical Techniques ; Electrodes ; Gold/chemistry ; Histidine/chemistry ; Imidazoles/chemistry ; Immobilized Proteins/chemistry ; Ions/chemistry ; Metals/chemistry ; Methylene Blue/chemistry ; Oligopeptides/chemistry ; Peptides/chemistry
    Chemical Substances His-His-His-His-His-His ; Imidazoles ; Immobilized Proteins ; Ions ; Metals ; Oligopeptides ; Peptides ; Histidine (4QD397987E) ; Gold (7440-57-5) ; imidazole (7GBN705NH1) ; Methylene Blue (T42P99266K)
    Language English
    Publishing date 2011-12-07
    Publishing country England
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 1472881-3
    ISSN 1364-548X ; 1359-7345 ; 0009-241X
    ISSN (online) 1364-548X
    ISSN 1359-7345 ; 0009-241X
    DOI 10.1039/c1cc15510e
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: An electrochemical peptide-based Ara h 2 antibody sensor fabricated on a nickel(II)-nitriloacetic acid self-assembled monolayer using a His-tagged peptide

    Zaitouna, Anita J / Rebecca Y. Lai

    Analytica chimica acta. 2014 May 30, v. 828

    2014  

    Abstract: We report, for the first time, the use of a Ni(II)-nitriloacetic acid (NTA) self-assembled monolayer (SAM) in the fabrication of an electrochemical peptide-based (E-PB) sensor for detection of anti-Ara h 2 antibodies. We compared the performance of the ... ...

    Abstract We report, for the first time, the use of a Ni(II)-nitriloacetic acid (NTA) self-assembled monolayer (SAM) in the fabrication of an electrochemical peptide-based (E-PB) sensor for detection of anti-Ara h 2 antibodies. We compared the performance of the sensor fabricated on a Ni(II)-NTA SAM using a His-tagged peptide with the sensor fabricated using the conventional approach via direct immobilization of a thiolated peptide. While both sensors responded only to the correct antibody in the presence of random antibodies, we observed differences between the sensors. Specifically, the detection limit of the His-tagged sensor was 1pM, significantly lower than the 200pM detection limit of the conventional thiolated sensor. More importantly, unlike our previously developed E-PB sensors, both sensors are regenerable and reusable. The thiolated sensor can be readily regenerated using guanidine hydrochloride; whereas the His-tagged sensor can be regenerated by direct displacement of the His-tagged probes using Ni(II) ions. Overall, our results show that both approaches are well-suited for E-PB sensor fabrication; more importantly, specific sensor properties such as detection limit and dynamic range can be tuned by simply using a different probe immobilization method.
    Keywords analytical chemistry ; antibodies ; detection limit ; electrochemistry ; guanidines ; ions ; nickel
    Language English
    Dates of publication 2014-0530
    Size p. 85-91.
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 1483436-4
    ISSN 1873-4324 ; 0003-2670
    ISSN (online) 1873-4324
    ISSN 0003-2670
    DOI 10.1016/j.aca.2014.04.033
    Database NAL-Catalogue (AGRICOLA)

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