Single variable domain antibody as a versatile building block for the construction of IgG-like bispecific antibodies

Bispecific antibodies (BsAb) have been traditionally utilized to redirect cytotoxic effector cells and agents to kill tumor cells expressing the target antigens. Recently a new concept is emerging to develop BsAb that simultaneously block the functions of two tumor-associated targets, eg., growth factor receptors, for enhanced antitumor efficacies. Broad clinical applications of BsAb have been, and still are, significantly hampered by the difficulty in producing the materials in sufficient quantity and quality by traditional approaches. Here we describe a recombinant approach for the production of an Fc domain-containing, IgG-like tetravalent BsAb, using a single variable domain (sVD) antibody as a versatile building block. In this method, a sVD of a defined specificity is genetically fused to either the N-terminus of the light chain or the C-terminus of the heavy chain of a functional IgG antibody of a different specificity. A model BsAb was constructed using a sVD to mouse platelet derived growth factor receptor alpha and a conventional IgG antibody to mouse platelet derived growth factor receptor beta. The BsAb were expressed in mammalian cells and purified to homogeneity by a one-step Protein A affinity chromatography. Further, the BsAb retained the antigen binding specificity and the receptor neutralizing activity of both of its parent antibodies. Importantly, the BsAb inhibited the activation of both its target receptors in tumor cells stimulated by both platelet derived growth factor AA and BB, whereas the parent monospecific antibody only inhibited the activation of a single receptor stimulated by its cognate ligand. This format of BsAb should be readily applicable to the production of other BsAb recognizing any pairs of antigens.     

Intracellular Abeta and cognitive deficits precede beta-amyloid deposition in transgenic arcAbeta mice

The brain pathology of Alzheimer's disease is characterized by abnormally aggregated Abeta in extracellular beta-amyloid plaques and along blood vessel walls, but the relation to intracellular Abeta remains unclear. To address the role of intracellular Abeta deposition in vivo, we expressed human APP with the combined Swedish and Arctic mutations in mice (arcAbeta mice). Intracellular punctate deposits of Abeta occurred concomitantly with robust cognitive impairments at the age of 6 months before the onset of beta-amyloid plaque formation and cerebral beta-amyloid angiopathy. beta-Amyloid plaques from arcAbeta mice had distinct dense-core morphologies with blood vessels appearing as seeding origins, suggesting reduced clearance of Abeta across blood vessels in arcAbeta mice. The co-incidence of intracellular Abeta deposits with behavioral deficits support an early role of intracellular Abeta in the pathophysiological cascade leading to beta-amyloid formation and functional impairment.     

Pilot test of cooperative learning format for training mental health researchers and black community leaders in partnership skills

To support reduction of racial disparities in mental health diagnosis and treatment, mental health researchers and black community-based organization (CBO) leaders need training on how to engage in collaborative research partnerships. In this study, we pilot tested a series of partnership skills training modules for researchers and CBO leaders in a collaborative learning format. Two different sets of three modules, designed for separate training of researchers and CBO leaders, covered considering, establishing and managing mental health research partnerships and included instructions for self-directed activities and discussions. Eight CBO leaders participated in 10 sessions, and six researchers participated in eight sessions. The effectiveness of the training content and format was evaluated through standardized observations, focus group discussions, participant evaluation forms and retrospective pre-/posttests to measure perceived gains in knowledge. Participants generally were satisfied with the training experience and gained new partnership knowledge and skills. Although the CBO leaders were more engaged in the cooperative learning process, this training format appealed to both audiences. Pilot testing demonstrated that: 1) our modules can equip researchers and CBO leaders with new partnership knowledge and skills and 2) the cooperative learning format is a well-received and suitable option for mental health research partnership training.     

Validity and reliability of the Disabilities of Arm,Shoulder, and Hand scale in dental students: A transnational study

This study aimed to evaluate the validity and reliability of the Disabilities of Arm, Shoulder, and Hand (DASH) scale in Brazilian and American dental students and assess the influence of demographic variables on disability in them. A cross-sectional observational study was conducted with a nonprobabilistic sample. The sample was composed of students of both genders from the School of Dentistry of Araraquara, State University of São Paulo (UNESP) (n = 288), and students from Stony Brook University, New York, NY, USA (n = 149). The disabilities of the upper limbs were estimated using the DASH scale. The samples were characterized by collecting information on gender, academic year, and sports and work activities. The refined bifactorial model presented goodness-of-fit indices for both countries. There was a significant effect of the variables gender and academic year for the Brazilian sample and the variable sports practices for the American sample. The refined bifactorial model was valid and reliable for the Brazilian and American populations. In this model, the removal of item 17 for the Brazilian sample and items 3, 13, and 23 for the American sample was necessary. Demographic variables such as gender, academic year, and sports practice contributed significantly to the level of disability in the study populations.     

Youth health outcomes from the Connect-to-Protect coalitions to prevent adolescent HIV infections

We assessed the relationships among HIV-related social and behavioral outcomes resulting from an adolescent-focused HIV structural change initiative in eight urban sites operating Connect-to-Protect coalitions. Over a 4-year period, annual cross-sectional panels of adolescents (N = 2248) completed an audio-computer-assisted interview, providing data on satisfaction with their communities as adolescent-supportive environments, internalized HIV stigma, lifetime HIV-testing, lifetime sexual risk-taking and number of sexual partners in the prior year. We used structural equation modeling to estimate hypothesized links between time since coalition mobilization to our social and behavioral outcomes. Over the 4 years, adolescents perceived their communities to become more supportive (p < .05). Positive perceptions of community support were associated with lower lifetime HIV sexual risk (p < .05). The effect of time on risk behavior was mediated by perceptions of community support. Stigma was unchanged over time. Stigma had damaging effects on risk behavior, effects which were also mediated by perceptions of community support. Special efforts are needed to address the deleterious effect of HIV stigma on high-risk urban adolescents.     

Mitigation of Oxidation in Therapeutic Antibody Formulations: a Biochemical Efficacy and Safety Evaluation of <Emphasis Type="Italic">N</Emphasis>-Acetyl-Tryptophan and L-Methionine

Purpose

Biotherapeutics can be susceptible to oxidation during manufacturing and storage. Free L-methionine is known to protect methionine residues in proteins from oxidation. Similarly, free tryptophan and other indole derivatives have been shown to protect tryptophan residues from oxidation. N-acetyl-DL-tryptophan was previously identified as a potentially superior antioxidant to tryptophan as it has a lower oxidation potential and produces less peroxide upon light exposure. This study sought to confirm the antioxidant efficacy and safety of N-acetyl-DL-tryptophan and L-methionine as formulation components for biotherapeutic drugs.

Methods

Antibodies were subjected to AAPH and light exposure in the presence of N-acetyl-DL-tryptophan and L-methionine. Oxidation in relevant CDR and Fc residues was quantified by peptide map. In silico, in vitro, and in vivo studies were performed to evaluate the safety of N-acetyl-DL-tryptophan and L-methionine.

Results

Peptide mapping demonstrated that N-acetyl-DL-tryptophan was effective at protecting tryptophans from AAPH stress, and that the combination of N-acetyl-DL-tryptophan and L-methionine protected both tryptophan and methionine from AAPH stress. The safety assessment suggested an acceptable safety profile for both excipients.

Conclusions

N-acetyl-tryptophan and L-methionine effectively reduce the oxidation of susceptible tryptophan and methionine residues in antibodies and are safe for use in parenteral biotherapeutic formulations.

     

Injection Drug Use Trajectories among Migrant Populations: A Narrative Review

Background: Dual epidemics of injection drug use and blood-borne disease, characterized as “syndemics,” are present in a range of settings. Behaviors that drive such syndemics are particularly prevalent among mobile drug-using populations, for whom cross-border migration may pose additional risks. Objectives: This narrative review aims to characterize the risk factors for injection drug use initiation associated with migration, employing a risk environment framework and focusing on the San Diego–Tijuana border region as the most dynamic example of these phenomena. Methods: Based on previous literature, we divide migration streams into three classes: intra-urban, internal, and international. We synthesized existing literature on migration and drug use to characterize how mobility and migration drive the initiation of injection drug use, as well as the transmission of hepatitis and HIV, and to delineate how these might be addressed through public health intervention. Results: Population mixing between migrants and receiving communities and the consequent transmission of social norms about injection drug use create risk environments for injection drug use initiation. These risk environments have been characterized as a result of local policy environments, injection drug use norms in receiving communities, migration-related stressors, social dislocation, and infringement on the rights of undocumented migrants. Conclusion: Policies that exacerbate risk environments for migrants may inadvertently contribute to the expansion of epidemics of injection-driven blood-borne disease. Successful interventions that address emerging syndemics in border regions may therefore need to be tailored to migrant populations and distinguish between the vulnerabilities experienced by different migration classes and border settings.