γδ T cell antigen receptor polyspecificity enables T cell responses to a broad range of immune challenges

γδ T cells are essential for immune defense and modulating physiological processes. While they have the potential to recognize large numbers of antigens through somatic gene rearrangement, the antigens which trigger most γδ T cell response remain unidentified, and the role of antigen recognition in γδ T cell function is contentious. Here, we show that some γδ T cell receptors (TCRs) exhibit polyspecificity, recognizing multiple ligands of diverse molecular nature. These ligands include haptens, metabolites, neurotransmitters, posttranslational modifications, as well as peptides and proteins of microbial and host origin. Polyspecific γδ T cells are enriched among activated cells in naive mice and the responding population in infection. They express diverse TCR sequences, have different functional potentials, and include the innate-like γδ T cells, such as the major IL-17 responders in various pathological/physiological conditions. We demonstrate that encountering their antigenic microbiome metabolite maintains their homeostasis and functional response, indicating that their ability to recognize multiple ligands is essential for their function. Human γδ T cells with similar polyspecificity also respond to various immune challenges. This study demonstrates that polyspecificity is a prevalent feature of γδ T cell antigen recognition, which enables rapid and robust T cell responses to a wide range of challenges, highlighting a unique function of γδ T cells.

Predictors of Neurocognitive Impairment in Spanish-Speaking Latinos Living with HIV in the United States using Newly Developed Neuropsychological Test Norms

Objective

HIV-associated neurocognitive impairment (NCI) is prevalent and impactful. Yet, there is an absence of published studies that investigate its correlates among Spanish-speaking Latinos living in mainland US- a demographic that represents a large and vulnerable segment of the HIV+ population. The goal of the current study was to examine predictors of NCI among Spanish-speaking Latinos with HIV living in the United States.

Participants and Method

153 Spanish-speaking Latinos living with HIV from the US-Mexico border region (Age: M = 38.2, SD = 9.7; Education: M = 10.9, SD = 3.6; 73% female; 56% AIDS) completed comprehensive neuropsychological, neuromedical, and psychiatric evaluations in Spanish. Scores across 7 cognitive domains were converted to a Global Deficit Score (GDS) based on T-scores on individual tests using newly developed, region specific, and demographically-corrected norms for Spanish-speaking Latinos. NCI was determined using cutoff of GDS > 0.5 (39.2% of sample). Examined predictors included HIV disease characteristics (e.g., AIDS status, current CD4 count, duration of antiretroviral therapy (ART) exposure) and psychiatric comorbidities.

Results

A multivariable logistic regression - including predictors that were associated with NCI in univariable analyses - showed a significant interaction between lifetime history of substance use disorder (LT SUD) and duration of ART exposure, after accounting for AIDS status (LR Chi2 = 3.99, p = 0.046). Stratified analyses showed that among participants who did not have LT SUD, longer ART exposure was associated with decreased NCI (p = 0.01), while rates of NCI among those with LT SUD were not influenced by months of ART exposure (p = 0.91).

Conclusions

Present findings showed that HIV disease burden and psychiatric characteristics might interact to impact NCI among Spanish-speaking Latinos. Considering these influences may help in the provision of comprehensive care to Spanish-speaking, Latino minority groups that suffer from NCI and HIV.

Normative Data for Wisconsin Card Sorting Test-64 Item in a Spanish Speaking Adult Population Living in the US/Mexico Border Region

Objective

The Wisconsin Card Sorting Test (WCST) is a commonly used test of executive functioning. We aimed to generate norms on the WCST-64 item version for Spanish-speakers living in the US.

Participants and Method

Healthy Spanish-speakers (N=189) were recruited (Age M = 38.2, SD = 10.3, range 19-60; Education M = 10.9, SD = 4.5, range 0-20; 59.3% female) from the US-Mexico border region. Participants completed the WCST-64 as part of a larger neuropsychological battery. Spearman correlations and Wilcoxon Rank-sum tests were used to assess associations between demographic variables and raw scores. T-scores enabling demographic corrections for various WCST-64 measures (Total Errors, Perseverative Responses, Perseverative Errors, and Number of Categories Completed) were obtained using fractional polynomial equations with corrections for age, education, and gender. Uncorrected percentile scores were reported for Failures to Maintain Set. Rates of neurocognitive impairment (NCI; T < 40) were calculated by applying the newly developed norms along with published norms for non-Hispanic (NH) White and African American English-speakers.

Results

Older age was significantly associated with worse performance, and higher education was linked to better performance on most WCST-64 raw scores. Current norms resulted in expected rates of NCI (14-16% across measures). Applying norms for NH-Whites overestimated NCI (38-52% across measures). Applying norms for African Americans yielded NCI rates closer to what would be expected, with milder misclassifications (NCI: Total Errors = 14%, Perseverative Responses = 19%, Perseverative Errors = 10%).

Conclusions

Regional normative data will improve interpretation of test performance on the WCST-64 for Spanish-speakers of Mexican origin living in the US and will facilitate a more valid analysis of neuropsychological profile patterns in this population. Future research will need to explore the generalizability of these norms to other groups.

Neurocognitive Impairment in Spanish-Speaking Latinos Living with Human Immunodeficiency Virus in the United States: Validation of Neuropsychological Tests Norms

Objective

Latinos in the US are at increased risk for HIV-associated neurocognitive impairment (NCI). Yet, most studies in this group have included English-speakers only. We investigated the rate and pattern of HIV-associated NCI in Spanish-speaking Latinos from the US-Mexico border region by utilizing newly developed norms for this group, and compared it to previously published norms for English-speaking non-Latino Whites and Blacks/African Americans.

Participants and Method

Participants included 153 HIV+ Spanish-speaking Latinos (Age: M = 38.2, SD = 9.7; Education: M = 10.9, SD = 3.6; 27% female; 56% AIDS) living in the greater San Diego area. Participants completed comprehensive neuropsychological, neuromedical and psychiatric assessments in Spanish. The neuropsychological test battery employed in this study - and used extensively in prior studies of HIV- assesses seven ability domains. Raw test scores were converted to demographically-adjusted T-scores using regional norms for Spanish-speakers, and for non-Latino Whites and Blacks. NCI was defined per established criteria.

Results

Rate of global NCI was 39% using norms for Spanish-speaking Latinos, compared to 64% with White norms and 18% with Black norms. Using norms for Spanish speakers, domain specific NCI among those impaired was highest in executive function (68%), speed of information processing (65%), learning (51%), and working memory (50%). The pattern of HIV associated NCI varied when norms developed for non-Latino Whites and Blacks were used.

Conclusions

HIV+ Spanish speakers showed similar rates of global NCI to those in other HIV+ populations, when norms developed for this group were used. In contrast, use of non-Latino White and Black norms resulted in misclassification of impairment. The pattern of NCI differed based on the norms used. Present findings highlight the importance of utilizing norms developed for Spanish-speakers in the US in order to obtain more precise and valid depictions of cognition in this population.

A-03 Ethnic/Racial Differences in Longitudinal Neurocognitive Change among People Living with HIV

HIV disproportionately affects Black and Latino people in the United States, but data on longitudinal neurocognitive patterns for these groups are scarce. This study evaluated the incidence and predictors of neurocognitive decline by ethnicity/race in a cohort of Black, Latino, and White people living with HIV (PLWH). Participants included 499 PLWH (43.5% White, 42.7% Black, 13.8% Latino; mean age at baseline = 43.5) from the six-site CNS HIV Anti-Retroviral Therapy Effects Research (CHARTER) study. Participants completed comprehensive neurocognitive and neuromedical evaluations over 3-7 study visits for an average of 2.8 years (SD = 1.1). Interpertation of neurocognitive change was based on published methods using regression-based norms that correct for baseline performance and practice effects. Survival analyses investigated the relationship between ethnicity/race and neurocognitive change, and predictors of neurocognitive decline. In follow-up, 108 participants (21.6%) declined, 311 (62.3%) remained stable, and 80 (16.0%) improved. In Cox proportional hazard models, hazard ratios for neurocognitive decline were increased for Latinos compared to Whites (HR = 2.19, 95%CI = 1.32-3.63, p = .002) and Blacks (HR = 1.87, 95%CI = 1.14-3.04, p = .01). Including significant covariates (baseline nadir CD4, hepatitis C Virus, and VACS Index: a composite marker of physical health among PLWH)did not significantly decrease the elevated risk for decline among Latinos. We found that Latino PLWH appear to have higher risk of neurocognitive decline compared to White and Black PLWH. Traditional markers of HIV disease and physical health at baseline did not explain this elevated risk of neurocognitive decline. Future research examining economic, socio-environmental, and culturally-relevant biomedical factors may help to explain this observed ethnic/racial disparity in longitudinal neurocognitive function in HIV.

Comparison of Rates of Impairment Between Three Sets of Normative Data for Spanish-speakers of Mexican Origin in a Healthy Cohort

Objective

With over 37 million Spanish-speakers, the US is the second country in the world with the largest number of Spanish-speakers. Identification of neurological dysfunction via neuropsychological testing for this language group requires knowledgeable application of available tests and normative data. Accordingly, we investigated whether rates of neurocognitive impairment (NCI) varied based on the Spanish language normative method used.

Method

Participants included 254 healthy native Spanish-speakers (Age: M = 37.3, SD = 10.4; Education: M = 10.7, SD = 4.3; 59% Female; 78.7% of known Mexican origin/descent) living in the US-Mexico border region. Participants completed the Hopkins Verbal Learning Test-Revised (HVLT-R), Trail Making Test (TMT) A&B, and Animal Naming in Spanish. Raw test scores were converted to demographically-adjusted T-scores based on normative adjustments developed for this population (Neuropsychological Norms for the US-Mexico Border Region in Spanish [NP-NUMBRS]) and norms developed based on samples in Mexico (Latin American Norms from Mexico [LAN-M] and NEUROPSI). Rates of NCI (T < 40) based on the different normative methods were compared via McNemar’s tests.

Results

Rates of NCI for NP-NUMBRS and NEUROPSI fell between the expected 15-17%. Compared to NP-NUMBRS, significantly lower rates were found when applying LAN-M for HVLT-R Total (4%) and Delayed Recall (8%), TMT-A (1%), and Animal Naming (10%; all ps < .0002). No significant differences were found for TMT-B (p > .05).

Conclusions

Present findings revealed that while the NP-NUMBRS and NEUROPSI norms yielded similar NCI rates, and LAN-M norms underestimated NCI on three tests. This highlights the importance of carefully considering available normative adjustments for Spanish-speakers when applying them to specific populations.

C-25 Neurocognitive Correlates of Chronological and Subjective Age Differences in Persons Living with HIV compared to those without HIV

Objective

Investigate the discrepancy between subjective and chronologic age by HIV-serostatus, and the association of this discrepancy with subjective neurocognitive functioning (NCF) and objective NCF.

Methods

One hundred nineteen persons living with HIV (PWLH) and 98 HIV-uninfected (HIV-) adults (Mage = 50.9; SDage = 7.9) completed a comprehensive neurobehavioral battery. Subjective age was assessed using a single-item question (i.e., “how old do you feel?”). The difference between chronologic and subjective age resulted in subjective age discrepancy scores (SADS). Subjective NCF was measured using the Patient’s Assessment of Own Functioning Inventory; objective NCF was measured using global demographically-corrected T-scores. Linear regressions examined the association between subjective and objective NCF with SADS, covarying for significant PLWH and HIV- group differences (i.e., education, sex, ethnicity, and lifetime Major Depressive Disorder).

Results

PLWH reported lower SADS (indicating closer correspondence between chronologic and subjective age) than their HIV- counterparts, who reported feeling much younger (p = .05; 95% CI: -5.4, .001). Among PLWH, better subjective NCF was significantly related to greater SADS (p = .0002; 95% CI: -.48, -.16). Objective NCF was not associated with SADS among persons with and without HIV.

Conclusions

Adults without HIV reported feeling younger than their chronologic age, whereas PLWH felt significantly closer to their chronologic age. SADS were negatively associated with only subjective NCF, among only PLWH. This suggests perceived cognitive functioning has a greater impact on psychological well-being among this group. Future research is warranted to delineate the relationship between HIV, subjective neurocognition, and psychosocial factors related to daily functioning to improve successful aging outcomes among this vulnerable population.

A New Immunomodulatory Role for Peroxisomes in Macrophages Activated by the TLR4 Ligand Lipopolysaccharide

Peroxisomes are proposed to play an important role in the regulation of systemic inflammation; however, the functional role of these organelles in inflammatory responses of myeloid immune cells is largely unknown. In this article, we demonstrate that the nonclassical peroxisome proliferator 4-phenyl butyric acid is an efficient inducer of peroxisomes in various models of murine macrophages, such as primary alveolar and peritoneal macrophages and the macrophage cell line RAW264.7, but not in primary bone marrow-derived macrophages. Further, proliferation of peroxisomes blocked the TLR4 ligand LPS-induced proinflammatory response, as detected by the reduced induction of the proinflammatory protein cyclooxygenase (COX)-2 and the proinflammatory cytokines TNF-α, IL-6, and IL-12. In contrast, disturbing peroxisome function by knockdown of peroxisomal gene Pex14 or Mfp2 markedly increased the LPS-dependent upregulation of the proinflammatory proteins COX-2 and TNF-α. Specifically, induction of peroxisomes did not affect the upregulation of COX-2 at the mRNA level, but it reduced the half-life of COX-2 protein, which was restored by COX-2 enzyme inhibitors but not by proteasomal and lysosomal inhibitors. Liquid chromatography-tandem mass spectrometry analysis revealed that various anti-inflammatory lipid mediators (e.g., docosahexaenoic acid) were increased in the conditioned medium from peroxisome-induced macrophages, which blocked LPS-induced COX-2 upregulation in naive RAW264.7 cells and human primary peripheral blood-derived macrophages. Importantly, LPS itself induced peroxisomes that correlated with the regulation of COX-2 during the late phase of LPS activation in macrophages. In conclusion, our findings identify a previously unidentified role for peroxisomes in macrophage inflammatory responses and suggest that peroxisomes are involved in the physiological cessation of macrophage activation.