Evaluation of community-based HIV self-testing delivery strategies on reducing undiagnosed HIV infection, and improving linkage to prevention and treatment services, among men who have sex with men in Kenya: a programme science study protocol.

BACKGROUND: HIV prevalence among men having sex with men (MSM) in Kenya is 18.2%. Despite scale-up of HIV testing services, many MSM remain unaware of their HIV status and thus do not benefit from accessing HIV treatment or prevention services. HIV self-testing (HIVST) may help address this gap. However, evidence is limited on how, when, and in what contexts the delivery of HIVST to MSM could increase awareness of HIV status and lead to early linkage to HIV treatment and prevention. METHODS: The study will be embedded within existing MSM-focused community-based HIV prevention and treatment programmes in 3 counties in Kenya (Kisumu, Mombasa, Kiambu). The study is designed to assess three HIV testing outcomes among MSM, namely a) coverage b) frequency of testing and c) early uptake of testing. The study will adopt a mixed methods programme science approach to the implementation and evaluation of HIVST strategies via: (i) a baseline and endline bio-behavioural survey with 1400 MSM; (ii) a socio-sexual network study with 351 MSM; (iii) a longitudinal qualitative cohort study with 72 MSM; (iv) routine programme monitoring in three sites; (v) a programme-specific costing exercise; and (vi) mathematical modelling. This protocol evaluates the impact of community-based implementation of HIV self-testing delivery strategies among MSM in Kenya on reducing the undiagnosed MSM population, and time for linkage to prevention, treatment and care following HIV self-testing. Baseline data collection started in April 2019 and the endline data collection will start in July 2020. DISCUSSION: This study is one of the first programme science studies in Sub-Saharan Africa exploring the effectiveness of integrating HIVST interventions within already existing HIV prevention and treatment programmes for MSM in Kenya at scale. Findings from this study will inform national best approaches to scale up HIVST among MSM in Kenya.

SHP-1-Pyk2-Src protein complex and p38 MAPK pathways independently regulate IL-10 production in lipopolysaccharide-stimulated macrophages.

The role of tyrosine phosphatase Src homology region 2 domain-containing phosphatase (SHP)-1 in LPS-activated cytokine production and inflammation was investigated by determining TNF-α and IL-10 production in splenic macrophages employing SHP-1-null (me/me) mouse model. LPS-stimulated me/me splenic macrophages secreted significantly less IL-10 with concomitantly elevated levels of TNF-α compared with wild-type (WT) macrophages irrespective of LPS dose and duration of stimulation. IL-10 significantly inhibited LPS-induced TNF-α production in both me/me and WT macrophages. The critical requirement for SHP-1 in regulating LPS-induced IL-10 and TNF-α production was confirmed by interfering with SHP-1 expression in WT macrophages and by reconstituting me/me macrophages with the SHP-1 gene. To delineate the role of SHP-1 in positive regulation of LPS-induced IL-10 production, signaling proteins representing SHP-1 targets were examined. The results reveal that tyrosine kinases Src and proline-rich tyrosine kinase 2 (Pyk2) regulate SHP-1-dependent LPS-induced IL-10 production and infer that optimal LPS-induced IL-10 production requires an assembly of a protein complex consisting of SHP-1-Pyk2-Src proteins. Moreover, LPS-induced IL-10 production also requires activation of the p38 MAPK independent of SHP-1 function. Overall, to our knowledge our results show for the first time that SHP-1 acts as a positive regulator of LPS-induced IL-10 production in splenic macrophages through two distinct and independent SHP-1-Pyk2-Src and p38 MAPK pathways.

Peroxisome proliferator-activated receptor (PPAR)α and -γ regulate IFNγ and IL-17A production by human T cells in a sex-specific way.

Women develop certain autoimmune diseases more often than men. It has been hypothesized that this may relate to the development of more robust T-helper (Th)1 responses in women. To test whether women exhibit a Th1 bias, we isolated naïve cluster of differentiation (CD)4(+) T cells from peripheral blood of healthy women and men and measured the proliferation and cytokine production by these cells in response to submaximal amounts of anti-CD3 and anti-CD28. We observed that CD4(+) T cells from women produced higher levels of IFNγ as well as tended to proliferate more than male CD4(+) T cells. Intriguingly, male CD4(+) T cells instead had a predilection toward IL-17A production. This sex dichotomy in Th cytokine production was found to be even more striking in the Swiss/Jackson Laboratory (SJL) mouse. Studies in mice and humans indicated that the sexual dimorphism in Th1 and Th17 cytokine production was dependent on the androgen status and the T-cell expression of peroxisome proliferator activated receptor (PPAR)α and PPARγ. Androgens increased PPARα and decreased PPARγ expression by human CD4(+) T cells. PPARα siRNA-mediated knockdown had the effect of increasing IFNγ by male CD4(+) T cells, while transfection of CD4(+) T cells with PPARγ siRNAs increased IL-17A production uniquely by female T cells. Together, our observations indicate that human T cells exhibit a sex difference in the production of IFNγ and IL-17A that may be driven by expressions of PPARα and PPARγ.

IL-6 production is positively regulated by two distinct Src homology domain 2-containing tyrosine phosphatase-1 (SHP-1)-dependent CCAAT/enhancer-binding protein ß and NF-κB pathways and an SHP-1-independent NF-κB pathway in lipopolysaccharide-stimulated bone marrow-derived macrophages.

Comparison of the inflammatory cytokine profile in bone marrow-derived macrophages (BMDMs) from normal and Src homology domain 2-containing tyrosine phosphatase-1 (SHP-1)-deficient Motheaten (me/me) mice revealed a dramatic suppression of IL-6 transcript and protein in me/me BMDMs after LPS stimulation. Interfering with SHP-1 expression using antisense SHP-1 oligonucleotides led to a significant downregulation of IL-6 in normal BMDMs. Conversely, reconstitution of me/me BMDMs with the SHP-1 gene using adenoviral vectors restored IL-6 production. Expression of only SHP-1 Src homology region 2 domains in normal BMDMs inhibited IL-6 production, confirming that IL-6 regulation depends on SHP-1 phosphatase activity. We further demonstrated that loss of SHP-1 function affects proper phosphorylation of Erk1/2 MAPKs and, to a lesser degree, of NF-κB downstream of TLR4 in BMDMs. Inefficient phosphorylation of Erk1/2 MAPKs abrogated the activation of C/EBPß transcription factor, which was reversed on restoration of SHP-1 function and led to a concomitant enhancement of IL-6 production. We demonstrate that IL-6 production is regulated by a complex network of signaling pathways that include SHP-1-dependent activation of Erk1/2-C/EBPß and NF-κB, in addition to SHP-1-independent IκB pathway through the activation of protein tyrosine kinases downstream of TLR4. Taken together, these results revealed for the first time, to our knowledge, a positive and critical role of SHP-1 in IL-6 regulation and dependence of Erk1/2-C/EBPß pathway in addition to that of IκB on SHP-1 activity required for IL-6 induction after LPS stimulation.