Anti-CD4 monoclonal antibody, clone PY-46 [APC]

Enteropathogenic bacterial infections are a global health issue associated with high mortality, particularly in developing countries. Efficient host protection against enteropathogenic bacterial infection is characterized by coordinated responses between immune and nonimmune cells. In response to infection in mice, innate immune cells are activated to produce interleukin (IL)-23 and IL-22, which promote antimicrobial peptide (AMP) production and bacterial clearance. IL-36 cytokines are proinflammatory IL-1 superfamily members, yet their role in enteropathogenic bacterial infection remains poorly defined. Using the enteric mouse pathogen, C. rodentium, we demonstrate that signaling via IL-36 receptor (IL-36R) orchestrates a crucial innate-adaptive immune link to control bacterial infection. IL-36R-deficient mice (Il1rl2(-/-)) exhibited significant impairment in expression of IL-22 and AMPs, increased intestinal damage, and failed to contain C. rodentium compared to controls. These defects were associated with failure to induce IL-23 and IL-6, two key IL-22 inducers in the early and late phases of infection, respectively. Treatment of Il1rl2(-/-) mice with IL-23 during the early phase of C. rodentium infection rescued IL-22 production from group 3 innate lymphoid cells (ILCs), whereas IL-6 administration during the late phase rescued IL-22-mediated production from CD4(+) T cell, and both treatments protected Il1rl2(-/-) mice from uncontained infection. Furthermore, IL-36R-mediated IL-22 production by CD4(+) T cells was dependent upon NF kappa B-p65 and IL-6 expression in dendritic cells (DCs), as well as aryl hydrocarbon receptor (AhR) expression by CD4(+) T cells. Collectively, these data demonstrate that the IL-36 signaling pathway integrates innate and adaptive immunity leading to host defense against enteropathogenic bacterial infection.

Background: Little is known about hospitalization in African adolescents with perinatally acquired HIV (PHIV+ adolescents). We described the incidence and causes of hospitalization in participants enrolled in the Cape Town Adolescent Antiretroviral Cohort in South Africa. Methods: Data collected from July 2013 to October 2018 from PHIV+ and HIV- adolescents were analyzed. Participants were assessed every 6 months and data on intercurrent hospitalization were abstracted. Causes of hospitalizations were classified according to ICD-10 codes. Descriptive statistics, time-to-event analysis and Poisson regression were used to describe causes and incidence and to determine incidence rate ratios for factors associated with hospitalization. Results: Five hundred fifteen PHIV+ and 109 HIV- participants had a median follow-up of 4.1 years [interquartile range (IQR): 3.7-4.6]. At enrollment HIV+ participants had a median duration of ART of 7.6 years (IQR: 4.6-9.2), median CD4 count of 713 cells/mm(3)(IQR: 561.0-957.5) and 387 (75%) had a viral load <50 copies/mL. There were 149 hospital admissions over 64 months. Crude incidence rates for hospitalization were 6.6 [95% confidence interval (CI): 5.7-7.8] and 2.2 (95% CI: 1.2-4.3) per 100-person-years (P= <0.01) in HIV + and HIV-, respectively. Ninety of 149 (60%) admissions in HIV+ participants were classified as non-infectious, 36/149 (24%) were infectious and 23/149 (16%) were "other HIV-related" or "unknown." Older age (15-19 years) and maintaining a CD4 >500 cells/cm(3)were associated with decreased risk of hospitalization: adjusted incidence rate ratios of 0.61 (CI: 0.44-0.86,P= <0.01) and 0.68 (CI: 0.49-0.94,P= 0.02), respectively. Conclusions: PHIV+ adolescents had a high incidence of hospitalization despite ART. Strategies addressing infectious and non-infectious morbidity must be strengthened.