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1.
Health Promot Pract ; 24(4): 623-635, 2023 07.
Article in English | MEDLINE | ID: mdl-36960782

ABSTRACT

Health and economic inequities among U.S. racial/ethnic minority women and children are staggering. These inequities underscore a dire need for intersectionality-informed, social-justice-oriented maternal and child (MCH) policies and programs for U.S. women and children. In response, we developed the "Intersectionality Policymaking Toolkit: Key Principles for an Intersectionality Informed Policymaking Process to Serve Diverse Women, Children and Families" to assist U.S. policymakers/aides, practitioners, and other stakeholders in developing more equitable MCH policies/programs. This article describes the Toolkit development process and initial assessments of acceptability and feasibility for use in MCH policymaking. Between 2018 and 2021, we utilized the process that the World Health Organization (WHO) used to develop its WHO Surgical Safety Checklist to develop the content (e.g., case studies) and format (i.e., structure), make strategic decisions (e.g., core items, primary audiences, timing of utilization), test concepts, and receive feedback. We convened a 2-day planning meeting with experts (n = 8) in intersectionality, policymaking, and MCH to draft the Toolkit. Next, we convened half-day workshops with policymaking and program leadership and staff in Washington, DC, New Orleans, LA, and Santa Fe, NM, to refine the Toolkit (n = 37). Then we conducted an initial assessment of the Toolkits' acceptability and feasibility using surveys (n = 21), followed by focus groups (n = 7). The resulting Toolkit distills Critical Race Theory's and intersectionality's most critical elements into a user-friendly modality to promote and enhance equitable MCH policies and programs for diverse U.S. women and families.


Subject(s)
Ethnicity , Intersectional Framework , Child , Humans , Female , Minority Groups , Policy Making , Public Policy
3.
Am J Orthopsychiatry ; 92(2): 133-143, 2022.
Article in English | MEDLINE | ID: mdl-34928641

ABSTRACT

We examined the association between social-structural stressors-racial discrimination, incarceration, and unemployment-and depressive symptoms among 578 predominantly low-income urban Black men, ages 18-45. We also examined the extent to which two protective factors-social support and problem-solving coping-moderated the relationship between social-structural stressors and depressive symptoms. Results showed that more everyday racial discrimination and incarceration, but not unemployment, significantly predicted more depressive symptoms. The links between discrimination, incarceration, and depressive symptoms were stronger for men who reported lower levels of problem-solving coping and social support than those with higher levels. Our study suggests that interventions emphasizing protective factors may help Black men cope with some of the deleterious effects of racial discrimination and incarceration. It also underscores a need for structural interventions that reduce racial discrimination and incarceration. Depression among Black men is not simply a biomedical or psychological condition, but also a critical health equity issue. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Subject(s)
Depression , Racism , Adaptation, Psychological , Adolescent , Adult , Black or African American/psychology , Black People , Depression/psychology , Humans , Male , Middle Aged , Racism/psychology , Young Adult
4.
Cult Health Sex ; 23(1): 1-18, 2021 01.
Article in English | MEDLINE | ID: mdl-32037967

ABSTRACT

Sexual partner types and partnership dynamics have important implications for condom use. Yet most HIV prevention research conceptualises condom use as individual-level rather than dyadic-level behaviour. Evidence of a generalised HIV epidemic in urban predominantly low-income US Black heterosexual communities highlights the need for a culturally and contextually-grounded understanding of partner types, partnership dynamics and condom use from the perspective of Black heterosexual men. We conducted individual interviews with 30 self-identified men between the ages of 18 and 44, 18 (60%) of whom reported at least two partner types in the last 6 months. Key findings include: (1) 'main and casual' partner types per the HIV prevention literature; (2) three casual-partner subtypes: primary, recurrent, and one-time casuals; (3) overlapping partnership dynamics between main partners, primary-casual partners and recurrent-casual partners, but not one-time casual partners; and (4) consistent condom use reported for one-time casual partners only. The study underscores the critical need for more condom promotion messages and interventions that reflect the dyadic and culturally-grounded realities of US Black heterosexual men's sexual partner types and partnership dynamics.


Subject(s)
Heterosexuality , Sexual Partners , Child, Preschool , Condoms , Humans , Infant , Male , Men , Sexual Behavior
5.
J Racial Ethn Health Disparities ; 8(5): 1139-1152, 2021 Oct.
Article in English | MEDLINE | ID: mdl-32964348

ABSTRACT

Gentrification-the process by which middle-class individuals (often White) move into lower-income neighborhoods (often Black), consequently displacing existing residents and changing the neighborhood's social character-is a relatively new and rapid phenomenon in Washington, DC. From 2000 to 2010, DC had the second fastest rate of gentrification in the USA. Gentrification is a major and disproportionate source of disadvantage for low-income Black DC residents. In light of the relative dearth of psychological research focused on gentrification, this study sought to answer the following research questions: What are Black men's experiences with gentrification in DC and how are Black men psychosocially affected by the gentrification of their neighborhoods? Data used in this study were obtained in Fall 2013 via nine semi-structured focus groups from nine DC neighborhood clusters. Participants were 83 self-identified Black men between the ages of 18 and 48 (M = 29.96, SD = 6.90) who reported predominantly low socioeconomic status. Black men's experiences with gentrification in DC included experiencing changing demographics and spaces, being discriminated against by police, blaming the Black community for gentrification and displacement and recognizing the positives of gentrification. Gentrification had negative psychosocial effects on participants, including race-based social exclusion, restricted mobility, reduced social cohesion and sense of community belonging, loss of control, and internalized blame. It is imperative that psychologists and other health professionals recognize and further explore the psychosocial and health consequences of gentrification on longtime Black residents and promote solutions to reduce the stress associated with this understudied driver of racial/ethnic health inequities.


Subject(s)
Black or African American/psychology , Poverty/ethnology , Residence Characteristics/statistics & numerical data , Social Change , Adolescent , Adult , Black or African American/statistics & numerical data , District of Columbia , Humans , Male , Middle Aged , Young Adult
6.
Am J Mens Health ; 14(4): 1557988320943352, 2020.
Article in English | MEDLINE | ID: mdl-32693659

ABSTRACT

Interventionists often prioritize quantitative evaluation criteria such as design (e.g., randomized controlled trials), delivery fidelity, and outcome effects to assess the success of an intervention. Albeit important, criteria such as these obscure other key metrics of success such as the role of the interactions between participants and intervention deliverers, or contextual factors that shape an intervention's activities and outcomes. In line with advocacy to expand evaluation criteria for health interventions, we designed this qualitative study to examine how a subsample of Black men in MEN Count, an HIV/STI risk reduction and healthy relationship intervention with employment and housing stability case management for Black men in Washington, DC, defined the intervention's success. We also examined the contextual factors that shaped participation in the study's peer counseling sessions. We conducted structured interviews with 38 Black men, ages 18 to 60 years (M = 31.1, SD = 9.33) who completed at least one of three peer counseling sessions. Analyses highlighted three key themes: (a) the favorable impact of Mr. Stroman, the lead peer counselor, on participants' willingness to participate in MEN Count and disclose their challenges-we dubbed this the "Stroman Effect"; (b) the importance of Black men intervention deliverers with relatable life experiences; and (c) how contextual factors such as the HIV/AIDS epidemic, needs for housing and employment services and safe spaces to talk about challenges, and absentee fathers shaped participation. We discuss the study's implications for sustainable programs after funding ends and future multilevel health interventions to promote health equity for poor urban Black men.


Subject(s)
Black or African American/statistics & numerical data , Community Health Services/organization & administration , Health Education/organization & administration , Heterosexuality/statistics & numerical data , Risk Reduction Behavior , Sexually Transmitted Diseases/prevention & control , Adult , Black or African American/psychology , Counseling , HIV Infections/prevention & control , Heterosexuality/psychology , Humans , Male , Men's Health , Middle Aged , Sexually Transmitted Diseases/psychology , Unemployment/statistics & numerical data , Young Adult
7.
J Sex Res ; 54(4-5): 577-603, 2017.
Article in English | MEDLINE | ID: mdl-28287844

ABSTRACT

Epistemologies of ignorance describe how ignorance influences the production of knowledge. Advancing an intersectional epistemologies of ignorance approach that examines how conscious (or unconscious) ignorance about racism, heterosexism, and classism shapes empirical knowledge about Black men's sexualities, we conducted a critical review of the behavioral and social science research on U.S. Black men, ages 18 and older, for two time frames: pre-1981 and the most recent decade, 2006-2016. Our search yielded 668 articles, which we classified into five categories: sexual violence, sexual experiences and expressions, sexual identities, cultural and social-structural influences, and sexual health and sexual risk. We found that most of the research, particularly pre-1981, centered the experiences of White heterosexual men as normative and implicitly constructed Black men as hypersexual or deviant. Most of the research also color-blinded White privilege and ignored how racism, heterosexism, and classism structured Black men's inequities. We also found notable exceptions to these trends. Black men who are gay, bisexual, or who have sex with men, and research on HIV risk were prominent in the past decade, as was research that emphasized the social-structural (e.g., poverty, heterosexism, racism) and cultural (e.g., masculinity, religion) contexts of Black men's lives and sexualities. We provide 10 recommendations to avoid intersectional epistemic ignorance in future research.


Subject(s)
Black or African American/ethnology , Men , Prejudice/ethnology , Sexual Behavior/ethnology , Sexuality/ethnology , Humans , Male , United States/ethnology
8.
Health Psychol ; 34(4): 314-27, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25822050

ABSTRACT

OBJECTIVE: Although Black heterosexual men (BHM) in the United States rank among those most affected by HIV, research about how safer sex messages shape their safer sex behaviors is rare, highlighting the need for innovative qualitative methodologies such as critical discursive psychology (CDP). This CDP study examined how: (a) BHM construct safer sex and masculinity; (b) BHM positioned themselves in relation to conventional masculinity; and (c) discursive context (individual interview vs. focus group) shaped talk about safer sex and masculinity. METHOD: Data included individual interviews (n = 30) and 4 focus groups (n = 26) conducted with 56 self-identified Black/African American heterosexual men, ages 18 to 44. RESULTS: Analyses highlighted 5 main constructions: (a) condoms as signifiers of "safe" women; (b) blaming women for STI/responsibility for safer sex; (c) relationship/trust/knowledge; (d) condom mandates; and (e) public health safer sex. Discourses positioned BHM in terms of conventional masculinity when talk denied men's agency for safer sex and/or contraception, or positioned women as deceitful, or apathetic about sexual risk and/or pregnancy. Notably, discourses also spotlighted alternative masculinities relevant to taking responsibility for safer sex or sexual exclusivity. Discursive context, namely the homosocial nature of focus group discussions, shaped how participants conversed about safer sex, and masculinity but not the content of that talk. CONCLUSION: In denying BHM's responsibility for safer sex, BHM's discourses about safer sex and masculinity often mirror public health messages, underscoring a critical need to sync these discourses to reduce sexual risk, and develop gender-transformative safer sex interventions for BHM.


Subject(s)
Black or African American/psychology , Heterosexuality/psychology , Masculinity , Men/psychology , Safe Sex/psychology , Sexual Behavior/psychology , Adolescent , Adult , Black or African American/ethnology , Condoms/statistics & numerical data , Female , Focus Groups/methods , Heterosexuality/ethnology , Humans , Male , Safe Sex/ethnology , Sexual Behavior/ethnology , Surveys and Questionnaires , United States/ethnology , Young Adult
9.
AIDS Care ; 26(8): 1050-7, 2014.
Article in English | MEDLINE | ID: mdl-24797317

ABSTRACT

In light of evidence that racial discrimination and posttraumatic stress symptoms (PTSS) are neither rare nor extraordinary for many Black urban men, we examined the relationship between everyday racial discrimination and sexual HIV risk behaviors in a predominantly low-income sample of 526 urban Black heterosexually identified men; 64% of whom were unemployed and 55% of whom reported a history of incarceration. We tested the hypothesis that PTSS would mediate the relationship between everyday racial discrimination and sexual risk. Participants in the predominantly low-income urban sample ranged in age from 18 to 45 (M = 28.80, SD = 7.57). Three multiple regression models were used to test the study's mediational model. As hypothesized, PTSS mediated the relationship between everyday racial discrimination and sexual risk behaviors. Most participants (97%) reported experiences with everyday racial discrimination. Results empirically support the notion of racial discrimination-based traumatic stress as a pathway to Black heterosexual men's increased sexual risk behaviors. Results also highlighted key demographic differences with older men reporting fewer PTSS and sexual risk behaviors compared with younger men. Incarceration was related to both PTSS and sexual risk, underscoring the role that incarceration may play in Black heterosexual men's adverse health outcomes. Our study highlights the need for more qualitative and quantitative research to understand the nature of PTSS in Black heterosexual men and mechanisms such as substance use that may link traumatic experiences and sexual risk. Future research could also assess experiences with childhood sexual abuse, violence, and incarceration to gain a more in-depth understanding of the sources of traumatic stress in Black heterosexual men's lives. We advocate for the development of community-based individual and structural-level interventions to help Black heterosexual men in urban areas develop effective strategies to cope with racial discrimination-based traumatic stress to reduce sexual HIV risk behaviors in Black communities.


Subject(s)
Black or African American/psychology , Heterosexuality/psychology , Racism/psychology , Stress Disorders, Post-Traumatic/epidemiology , Unsafe Sex/psychology , Urban Population/statistics & numerical data , Adolescent , Adult , Age Factors , Cross-Sectional Studies , HIV Infections/psychology , HIV Infections/transmission , Humans , Male , Middle Aged , Risk-Taking , Young Adult
10.
Am J Mens Health ; 7(4 Suppl): 31S-42S, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23549304

ABSTRACT

Although the disproportionate toll of HIV/AIDS among Black heterosexuals, particularly in low-income U.S. urban areas is well documented, Black heterosexual men are rarely the explicit focus of HIV prevention messages, research, and interventions. We conducted 4 focus groups with 28 Black men, aged 19 to 51 years, who were enrolled in the workforce and fatherhood development program of a local community-based organization to examine (a) the priority and role of HIV/AIDS in their lives and (b) their HIV prevention needs. Although none articulated HIV as a top life priority, respondents nonetheless prioritized educating their children about HIV prevention and protecting their main partners from HIV if they had other sexual partners. Analyses demonstrated that participants said they wanted and needed: to learn how to talk to partners about HIV testing and use condoms when tempted not to do so, and more discussion-oriented educational opportunities to learn and exchange prevention strategies.


Subject(s)
Black or African American , HIV Infections/prevention & control , Health Behavior/ethnology , Health Education , Safe Sex , Acquired Immunodeficiency Syndrome/ethnology , Acquired Immunodeficiency Syndrome/prevention & control , Adult , Focus Groups , HIV Infections/ethnology , Health Knowledge, Attitudes, Practice , Heterosexuality/ethnology , Humans , Male , Middle Aged , Needs Assessment , Primary Prevention/methods , Risk Assessment , Risk-Taking , Sexual Behavior , Sexually Transmitted Diseases/ethnology , Sexually Transmitted Diseases/prevention & control , Socioeconomic Factors , United States , Young Adult
11.
AIDS Behav ; 17(1): 407-18, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22437347

ABSTRACT

Numerous studies document the adverse impact of racial discrimination on African Americans' health outcomes, but few have focused on HIV risk. We examined the relationship between racial discrimination and sexual risk in a sample of 526 Black heterosexual men and tested the hypothesis that social support would moderate this relationship. Participants in the predominantly low-income urban sample ranged in age from 18 to 45. High social support had a buffering impact on the relationship between racial discrimination and sexual risk. Among men reporting high racial discrimination, those with more social support reported less sexual risk than men with low social support. Men who reported high racial discrimination and low social support reported more sexual risk than men in any of the other groups. The study highlights social support as an important but understudied protective factor that may reduce sexual risk for Black heterosexual men who report high levels of racial discrimination.


Subject(s)
Black People/psychology , Heterosexuality/psychology , Racism/psychology , Risk-Taking , Social Support , Unsafe Sex/psychology , Adolescent , Adult , Cross-Sectional Studies , Female , HIV Infections/psychology , HIV Infections/transmission , Humans , Male , Middle Aged , Philadelphia , Regression Analysis , Socioeconomic Factors , Surveys and Questionnaires , Young Adult
12.
Cult Health Sex ; 13(5): 545-59, 2011 May.
Article in English | MEDLINE | ID: mdl-21390949

ABSTRACT

Research documents the link between traditional ideologies of masculinity and sexual risk among multi-ethnic male adolescents and White male college students, but similar research with Black heterosexual men is scarce. This exploratory study addressed this gap through six focus groups with 41 Black, low- to middle-income heterosexual men aged 19 to 51 years in Philadelphia, PA. Analyses highlighted two explicit ideologies of masculinity: that Black men should have sex with multiple women, often concurrently, and that Black men should not be gay or bisexual. Analyses also identified two implicit masculinity ideologies: the perception that Black heterosexual men cannot decline sex, even risky sex, and that women should be responsible for condom use. The study's implications for HIV prevention with Black heterosexual men are discussed.


Subject(s)
Black or African American , HIV Infections/psychology , Masculinity , Social Identification , Adult , Condoms/statistics & numerical data , Focus Groups , HIV Infections/epidemiology , HIV Infections/transmission , Humans , Interview, Psychological , Male , Middle Aged , United States/epidemiology , Young Adult
13.
J Immunol ; 161(6): 3161-8, 1998 Sep 15.
Article in English | MEDLINE | ID: mdl-9743384

ABSTRACT

Staphylokinase (Sak), a 16-kDa protein secreted by Staphylococcus aureus, induces fibrin-specific thrombolysis in patients with thrombotic disorders. However, Sak also elicits high titers of neutralizing Abs that persist for several months and preclude its repeated use in humans. To identify the antigenic determinants of Sak recognized by humans, a phage-displayed library of Sak variants was selected for mutants that escape binding to an affinity matrix derivatized with patient-specific polyclonal anti-Sak Abs. Fifty-six escape Sak variants were identified after three selection cycles using human polyclonal anti-Sak IgGs obtained from four different patients. DNA sequencing revealed 213 amino acid substitutions, of which 73% were found at 25 positions clustered in eight discontinuous Sak antigenic segments. Although each antigenic segment was recognized to a variable extent by each patient antiserum, the main epitopes of Sak in all patients were roughly targeted to two large discontinuous areas covering 35% of the solvent-accessible surface of Sak. The antigenic area I comprises three segments centered on residues 66, 73, and 135, while the antigenic area II consists of four segments centered on positions 20, 95, 102, and 121. These results suggest that a secondary immune response against Sak can occur in patients, and confirm an initial site-directed mutagenesis study wherein amino acid Lys74 was shown to play a prominent antigenic role. Comprehensive mapping of the most relevant sites of Sak that are antigenic for humans will guide efforts to modulate the immunogenicity of this therapeutically important molecule.


Subject(s)
Antigens, Bacterial/chemistry , Epitope Mapping/methods , Epitopes, B-Lymphocyte/chemistry , Immunodominant Epitopes/chemistry , Metalloendopeptidases/immunology , Peptide Library , Staphylococcus aureus/immunology , Amino Acid Substitution/genetics , Amino Acid Substitution/immunology , Antibodies, Bacterial/chemistry , Antigens, Bacterial/genetics , Antigens, Bacterial/immunology , Epitopes, B-Lymphocyte/immunology , Genetic Variation/immunology , Humans , Immunodominant Epitopes/immunology , Immunoglobulin G/chemistry , Inoviridae/genetics , Inoviridae/immunology , Metalloendopeptidases/chemistry , Metalloendopeptidases/genetics , Models, Molecular , Mutation , Staphylococcus aureus/enzymology , Staphylococcus aureus/genetics
14.
J Mol Biol ; 269(5): 704-18, 1997 Jun 27.
Article in English | MEDLINE | ID: mdl-9223635

ABSTRACT

Since most antibodies directed against protein antigens recognize epitopes composed of several discontinuous segments of the polypeptide chain, attempts to delineate the amino acids constituting these epitopes with the use of linear peptides have generally been unsuccessful. Here, a method is described based on error-prone PCR, phage display and negative selection, whereby amino acid residues constituting the functional epitope are identified in the context of the native protein. First a library of randomized antigen variants containing most single, double and triple amino acid mutants generated by single nucleotide substitutions is produced by error-prone PCR amplification of the DNA sequence encoding the protein antigen. The phage-displayed library is then negatively selected for epitope loss mutants by passing through an affinity matrix derivatized with a specific antibody and positively selected for retention of function. This method was applied to the mapping of the epitopes of two murine monoclonal antibodies (MA-7H11 and MA-3G10) on staphylokinase, a 136 amino acid plasminogen activator secreted by some strains of Staphylococcus aureus. After two negative/positive selection cycles, DNA sequencing of several clones revealed preferential amino acid mutations at positions 35 and 130 (with MA-7H11), and at positions 62, 66 and 136 (with MA-3G10). Affinity measurements of staphylokinase variants carrying single amino acid mutations at these positions confirmed their contribution to the free energy of binding to MA-7H11 and MA-3G10. This approach may be useful for isolating mutants with altered antigenic or functional properties and in general to map critical regions for protein-protein interactions.


Subject(s)
Antibodies, Bacterial/immunology , Antigens, Bacterial/immunology , Epitope Mapping/methods , Fibrinolytic Agents/immunology , Metalloendopeptidases/immunology , Amino Acid Sequence , Antibodies, Monoclonal , Antibody Specificity , Antigenic Variation , Base Sequence , Inoviridae/genetics , Molecular Sequence Data , Mutagenesis , Peptide Library , Selection, Genetic , Sequence Homology, Amino Acid
15.
Circulation ; 95(2): 455-62, 1997 Jan 21.
Article in English | MEDLINE | ID: mdl-9008464

ABSTRACT

BACKGROUND: The "charged cluster-to-alanine" substitution variants SakSTAR(K35A,E38A,K74A,E75A,R77A) and SakSTAR(K74A,E75A,R77A,E80A,D82A), previously identified as SakSTAR.M38 and SakSTAR.M89, respectively, induce less antibody formation in patients than wild-type recombinant staphylokinase (SakSTAR), but their specific activities are reduced by 50%. Therefore, the effect of the reversal of one or more of these substituted amino acids on the ratio of activity to antigenicity was studied. METHODS AND RESULTS: Fourteen mutants with one to four "alanine-to-wild-type" reversals were expressed in Escherichia coli and highly purified (> 95%). In rabbits immunized with wild-type SakSTAR, the combined K35,E38,K74,E75,R77 or K74,E75,R77,E80,E82 epitope accounted for only 30% of antibody absorption from plasma, and no clear immunodominant residue could be identified. In baboons immunized with SakSTAR, the K35,E38 and K74,E75,R77 epitopes or the K74,E75,R77 and E80,D82 epitopes contributed equally to account for 50% of total antibody binding, but no immunodominant residues were apparent. In pooled plasma from patients with peripheral arterial occlusion treated with wild-type SakSTAR, about 40% of the antibodies depended on K74 of epitope K74,E75,R77 for binding, whereas epitopes K35,E38 and E80,D82 had a negligible contribution toward antibody recognition. CONCLUSIONS: The recognition pattern by SakSTAR variants of antibodies induced with wild-type SakSTAR differs markedly among species. This implies that a systematic evaluation of reduced antigen recognition and antibody induction in humans will require the development of human or humanized systems. Surprisingly, SakSTAR(K74), with a single substitution of Lys74 with Ala, had an intact specific activity but did not absorb 40% of the antibodies induced in patients by treatment with wild-type SakSTAR.


Subject(s)
Antibodies/immunology , Fibrinolytic Agents/immunology , Genetic Variation , Metalloendopeptidases/genetics , Metalloendopeptidases/immunology , Animals , Antibodies, Monoclonal/immunology , Blood/drug effects , Cricetinae , Epitopes , Fibrinolytic Agents/pharmacology , Humans , Injections , Metalloendopeptidases/pharmacology , Mice , Myocardial Infarction/blood , Papio , Rabbits , Recombinant Proteins , Species Specificity
16.
Circulation ; 94(2): 197-206, 1996 Jul 15.
Article in English | MEDLINE | ID: mdl-8674179

ABSTRACT

BACKGROUND: Recombinant staphylokinase offers promise for thrombolytic therapy in acute myocardial infarction, but it is immunogenic. Although reduced immunogenicity of heterologous proteinaceous drugs by protein engineering has not previously been reported, an attempt was made to achieve this in staphylokinase by site-specific mutagenesis. METHODS AND RESULTS: Biospecific interaction analysis of a panel of 17 murine monoclonal antibodies against recombinant staphylokinase (SakSTAR variant) identified three nonoverlapping immunodominant epitopes, two of which could be eliminated by substitution mutagenesis of clusters of two or three charged amino acids with alanine. Circulating anti-staphylokinase antibodies elceted in patients by treatment with SakSTAR were incompletely (< 90%) absorbed by these mutants. Therefore, the combination variants K35A,E38A,K74A,E75A,R77A (SakSTAR.M38) and K74A,E75A,R77A,E80A,D82A (SakSTAR.M89) were constructed, expressed in Escherichia coli, highly purified by ion-exchange and hydrophobic interaction chromatography, and characterized. These variants had specific activities that were approximately half that of SakSTAR, and they combined the reduced reactivity with the panels of monoclonal antibodies of their parent molecules. Absorption of circulating antibodies elicited in patients by treatment with SakSTAR was incomplete in 13 of 16 patients (median values, 68% and 65% with SakSTAR.M38 and SakSTAR.M89, respectively). CONCLUSIONS: SakSTAR contains three immunodominant epitopes, two of which were eliminated by site-directed mutagenesis, yielding combination mutants with relatively maintained specific activities that were not recognized by a significant fraction of the antibodies elicited in patients by treatment with wildtype SakSTAR. These mutants appear to be suitable for more detailed investigation of their thrombolytic and antigenic properties.


Subject(s)
Epitopes/analysis , Fibrinolytic Agents/immunology , Metalloendopeptidases/immunology , Amino Acid Sequence , Antibodies, Monoclonal , Base Sequence , Chemical Phenomena , Chemistry, Physical , Humans , Metalloendopeptidases/isolation & purification , Molecular Sequence Data , Mutagenesis , Recombinant Proteins/immunology , Recombinant Proteins/isolation & purification
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