Inhibition of antibody production in vivo by pre-stimulation of Toll-like receptor 4 before antigen priming is caused by defective B-cell priming and not impairment in antigen presentation.

Stimulation of Toll-like receptor 4 (TLR4) induces not only innate but also adaptive immune responses, and has been suggested to exert adjuvant effects. Additional to such positive effects, pre-stimulation of TLR4 induces endotoxin tolerance where animals are unresponsive to subsequent lethal challenges with lipopolysaccharide (LPS). We examined the effects of pre-stimulation of TLR4 using an agonistic anti-TLR4 mAb (UT12) on antibody production in vivo. Pre-injection of UT12 prior to both primary and secondary immunization completely inhibited antigen-specific antibody responses. Cellular analysis revealed that the inhibition was not due to impairment of T-cell activation. Accordingly, T-helper activities in UT12 pre-injected mice were not impaired. In contrast, B-cell priming was defective in UT12 pre-injected mice. The observation that the expression of activation markers such as CD69 and CD86 on B cells was blocked by UT12 pre-injection supports this. Interestingly, UT12 pre-injection only showed inhibitory effects at the primary and not the secondary immunization. These results provide important information concerning the regulatory mechanisms of antibody production, especially in endotoxin-tolerant states.

Glycemic control as the main determinant factor of serum VEGF levels in type 2 diabetes mellitus patients.

Introduction. Diabetes mellitus (DM) is a main endocrine disorder that may cause vascular complications as the disease progresses. Vascular endothelial growth factor (VEGF) has been linked to the development of micro and macrovascular diabetic complications. This study aimed to assess several factors including blood pressure, body mass index, lipid profile, kidney function, and glycemic control that may provide the rise of serum VEGF levels in type 2 DM subjects. Methods. This cross-sectional study was carried out among 65 type 2 DM subjects. Systole, diastole, mean arterial pressure (MAP), and body mass index (BMI) were measured. The levels of serum VEGF were measured by Enzyme-linked immunosorbent assay (ELISA), Hemoglobin A1c (HbA1c) levels were measured by latex agglutination inhibition test, while serum glucose, lipid profiles, urea, and creatinine levels were tested by enzymatic photometric method. Results. The levels of serum VEGF had a significant correlation with BMI (p = 0.001, r = 0.397), fasting plasma glucose (FPG) (p = 0.001, r = 0.418), HbA1c (p < 0.001, r = 0.600), systole (p = 0.001), r = 0.397), diastole (p = 0.021, r = 0.286), and MAP (p = 0.001, r = 0.001). Further multivariate linear regression analysis revealed that HbA1c logarithm (log) was the determinant factor of VEGF levels (p < 0.001, ß = 0.631, Adjusted R2 = 38.9%) Conclusion. HbA1c is the main determinant factor of serum VEGF levels among type 2 DM patients.

Excess mortality attributable to antimicrobial-resistant bacterial bloodstream infection at a tertiary-care hospital in Indonesia.

The burden of antimicrobial-resistant (AMR) infections in low and middle-income countries (LMICs) is largely unknown. Here, we evaluate attributable mortality of AMR infections in Indonesia. We used routine databases of the microbiology laboratory and hospital admission at Dr. Wahidin Sudirohusodo Hospital, a tertiary-care hospital in South Sulawesi from 2015 to 2018. Of 77,752 hospitalized patients, 8,341 (10.7%) had at least one blood culture taken. Among patients with bacteriologically confirmed bloodstream infections (BSI), the proportions of patients with AMR BSI were 78% (81/104) for third-generation cephalosporin-resistant (3GCR) Escherichia coli, 4% (4/104) for 3GCR plus carbapenem-resistant E. coli, 56% (96/171) for 3GCR Klebsiella pneumoniae, 25% (43/171) for 3GCR plus carbapenem-resistant K. pneumoniae, 51% (124/245) for methicillin-resistant Staphylococcus aureus, 48% (82/171) for carbapenem-resistant Acinetobacter spp., and 19% (13/68) for carbapenem-resistant Pseudomonas aeruginosa. Observed in-hospital mortality of patients with AMR BSI was 49.7% (220/443). Compared with patients with antimicrobial-susceptible BSI and adjusted for potential confounders, the excess mortality attributable to AMR BSI was -0.01 (95% CI: -15.4, 15.4) percentage points. Compared with patients without a BSI with a target pathogen and adjusted for potential confounders, the excess mortality attributable to AMR BSI was 29.7 (95%CI: 26.1, 33.2) percentage points. This suggests that if all the AMR BSI were replaced by no infection, 130 (95%CI: 114, 145) deaths among 443 patients with AMR BSI might have been prevented. In conclusion, the burden of AMR infections in Indonesian hospitals is likely high. Similar large-scale evaluations should be performed across LMICs to inform interventions to mitigate AMR-associated mortality.

Performance of Xpert MTB/RIF and sputum microscopy compared to sputum culture for diagnosis of tuberculosis in seven hospitals in Indonesia.

Introduction: Tuberculosis (TB) is a major public health concern in Indonesia, where the incidence was 301 cases per 100,000 inhabitants in 2020 and the prevalence of multi-drug resistant (MDR) TB is increasing. Diagnostic testing approaches vary across Indonesia due to resource limitations. Acid-fast bacilli (AFB) smear is widely used, though Xpert MTB/RIF has been the preferred assay for detecting TB and rifampicin resistance since 2012 due to higher sensitivity and ability to rapidly identify rifampicin resistance. However, <1,000 Xpert instruments were available in Indonesia as of 2020 and the Xpert supply chain has suffered interruptions. Methods: We compared the performance of Xpert MTB/RIF and AFB smear to facilitate optimization of TB case identification. We analyzed baseline data from a cohort study of adults with pulmonary TB conducted at seven hospitals across Indonesia. We evaluated sensitivity and specificity of AFB smear and Xpert MTB/RIF using Mycobacterium tuberculosis (Mtb) culture as the gold standard, factors associated with assay results, and consistency of Xpert MTB/RIF with drug susceptibility test (DST) in detecting rifampicin resistance. Results: Sensitivity of AFB smear was significantly lower than Xpert MTB/RIF (86.2 vs. 97.4%, p-value <0.001), but specificity was significantly better (86.7 vs. 73.3%, p-value <0.001). Performance varied by hospital. Positivity rate for AFB smear and Mtb culture was higher in subjects with pulmonary cavities and in morning sputum samples. Consistency of Xpert MTB/RIF with DST was lower in those with rifampicin- sensitive TB by DST. Discussion: Additional evaluation using sputa from primary and secondary Indonesian health centers will increase the generalizability of the assessment of AFB smear and Xpert MTB/RIF performance, and better inform health policy. Clinical trial registration: [https://clinicaltrials.gov/], identifier [NCT027 58236].

Lipocalin 2 could predict circulating MMP9 levels in patients with breast cancer.

OBJECTIVES: Breast cancer is the most prevalent carcinoma found in Indonesian women, and its incidence remains high worldwide. Lipocalin 2 has been linked with the progression of breast cancer. Matrix metalloproteinase 9 (MMP9) is an enzyme that has an important role in angiogenesis. We investigated the relationship between lipocalin 2 and MMP9 and the ability of lipocalin 2 for predicting MMP9 levels in female patients with breast cancer. METHOD: A total of 55 female patients with breast cancer were enrolled in this cross-sectional study. Lipocalin 2 and MMP9 were measured by enzyme-linked immunosorbent assay. RESULTS: Lipocalin 2 was significantly correlated with MMP9 levels (r = 0.756, p < 0.001). Lipocalin 2 levels could describe the MMP9 levels (𝛽 = 0.76, p < 0.001, R2 = 56.9%). CONCLUSION: Higher lipocalin 2 levels in female patients with breast cancer indicate higher MMP9 levels. Lipocalin 2 can be used to predict MMP9 levels.

Anthropometric features in predicting insulin resistance among non-menopausal Indonesian adult females.

INTRODUCTION: The prevalence of obesity is increasing worldwide in high, low, and middle-income countries such as Indonesia. Obesity rate is higher in females in Indonesia. Obesity has important contribution in the occurrence of insulin resistance (IR) and type 2 diabetes mellitus. Several anthropometric measurements such as waist circumference (WC), body mass index (BMI), body mass (BM), total body fat percentage (Fat%) and visceral fat (VF) are related to IR. This study aimed to investigate which of those measurements could be used as a better predictor of IR in non-menopausal Indonesian adult females. METHODS: Total of 80 non-menopausal Indonesian adult females ranging from 21 to 40 years were recruited in this study. Insulin resistance was measured by using Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) equation. Subjects with HOMA-IR index >75th percentile with cut-off 2.74 were defined as IR. Waist circumference, BMI and BM were measured, while TF and VF were measured by bioelectrical impedance analysis (BIA). RESULTS: HOMA-IR had significant correlation with WC (r = 0.563, p < 0.001), BMI (r = 0.537, p < 0.001), BM (r = 0.515, p < 0.001), VF (r = 0.515, p < 0.001), Fat% (r = 0.490, p < 0.001). The area under curve of VF (0.809), BMI (0.807), WC (0.805), and BM (0.799) are slightly larger than and Fat% (0.766). CONCLUSION: Insulin resistance had strong correlation with all anthropometric measurements, but the correlation was less significant with Fat%.

Body Mass, Total Body Fat Percentage, and Visceral Fat Level Predict Insulin Resistance Better Than Waist Circumference and Body Mass Index in Healthy Young Male Adults in Indonesia.

The incidence of obesity which leads to insulin resistance (IR) and metabolic disorder is increasing in developing countries, including Indonesia. Male adults have a higher risk of abdominal obesity than females. This is associated with cardiometabolic disorders. Several anthropometric measurements have been proposed to predict IR. The aim of this study was to investigate whether body mass, body mass index (BMI), waist circumference (WC), body fat percentage (BF) or visceral fat level (VF) could become a better predictor of IR in healthy young male adults. A total of 140 healthy young male adults ranging from 18⁻25 years were recruited in the study. Insulin resistance was measured by calculating their Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Subjects with a HOMA-IR value ≥75th percentile, with cut off 3.75, were defined as IR. Anthropometric measurements including body weight, BMI, and WC were performed, whereas BF and VC were measured using bioelectrical impedance analysis (BIA). IR had a strong correlation with body weight, BMI, WC, BF, and VF. In the area under the curve of body mass, BF and VF were slightly greater than WC and BMI. Anthropometric measurements correlated strongly with IR but body weight, BF, VF had a stronger correlation than WC and BMI in healthy young male adults.

Preparation and characterization of agonistic monoclonal antibodies against Toll-like receptor 4-MD-2 complex.

Ligands for toll-like receptors (TLR) are known to induce a variety of immune responses. Selective induction of desirable responses would be important for the treatment of individual diseases with various pathogenesis. For this purpose, we established six MAbs against the TLR4/MD-2 complex (UT MAbs) from TLR4(-/-) mice or MD-2(-/-) mice. Three MAbs (UT12, 18, and 22) induced NF-kappaB activation and production of pro-inflammatory cytokines, but the other three (UT15, 41, and 49) did not induce such cell responses. Unlike lipopolysaccharide (LPS), agonistic UT MAbs did not require serum components for the functions. UT41 and UT49 recognized TLR4 in the absence of MD-2. On the other hand, the other four MAbs reacted to the TLR4/MD-2 complex, but not to solo TLR4. Agonistic UT MAbs shared the epitopes, but non-agonistic UT15 reacted to distinct epitope on the complex. UT MAbs appear to be useful analyzing the molecular mechanism of TLR signaling and will contribute to the development of novel immunotherapies.

Induction of long-term lipopolysaccharide tolerance by an agonistic monoclonal antibody to the toll-like receptor 4/MD-2 complex.

We have established an agonistic monoclonal antibody, UT12, that induces stimulatory signals comparable to those induced by lipopolysaccharide (LPS) through Toll-like receptor 4 and MD-2. UT12 activated nuclear factor kappaB and induced the production of proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) in peritoneal exudative cells. In addition, mice injected with UT12 rapidly fell into endotoxin shock concomitant with the augmentation of serum TNF-alpha and IL-6 levels, followed by death within 12 h. On the other hand, when the mice were pretreated with a sublethal dose of UT12, the mice survived the subsequent lethal LPS challenges, with significant suppression of serum TNF-alpha and IL-6, indicating that UT12 induced tolerance against LPS. This effect of UT12 was maintained for at least 9 days. In contrast, the tolerance induced by LPS continued for less than 3 days. These results illuminate a novel potential therapeutic strategy for endotoxin shock by the use of monoclonal antibodies against the Toll-like receptor 4/MD-2 complex.

Penta-acylated lipopolisaccharide binds to murine MD-2 but does not induce the oligomerization of TLR4 required for signal transduction.

A mutant lipopolysaccharide (LPS) lacking a myristate chain in lipid A was shown to be non-pathogenic both in humans and mice. The mutant penta-acylated LPS from the lpxM-strain did not induce TNF-alpha production in murine peritoneal macrophages, or activation of NF-kappaB in transfected cells expressing murine TLR4/MD-2. We prepared a recombinant murine MD-2 in Escherichia coli (E. coli), and examined the binding function. Unexpectedly, specific binding was detected to both wild type and mutant LPS. However, the mutant LPS did not induce conformation changes or oligomerization of TLR4, which have been shown to be required for signal transduction. Mutant LPS appears to fail to induce appropriate conformational changes, resulting in oligomerization of the murine complex for triggering cell responses.

Toll-like receptors on hematopoietic progenitor cells stimulate innate immune system replenishment.

Toll-like receptors (TLRs) are best known for their ability to recognize microbial or viral components and initiate innate immune responses. We showed here that TLRs and their coreceptors were expressed by multipotential hematopoietic stem cells, whose cell cycle entry was triggered by TLR ligation. TLR expression also extended to some of the early hematopoietic progenitors, although not the progenitor cells dedicated to megakaryocyte and erythroid differentiation. TLR signaling via the Myd88 adaptor protein drove differentiation of myeloid progenitors, bypassing some normal growth and differentiation requirements, and also drove lymphoid progenitors to become dendritic cells. CD14 contributed to the efficiency of lipopolysaccharide (LPS) recognition by stem and progenitor cells, and LPS interacted directly with the TLR4/MD-2 complex on these cells in bone marrow. Thus, the preferential pathogen-mediated stimulation of myeloid differentiation pathways may provide a means for rapid replenishment of the innate immune system during infection.

Identification of a novel isoform of MD-2 that downregulates lipopolysaccharide signaling.

MD-2 is an association molecule of Toll-like receptor 4 and is indispensable for the recognition of lipopolysaccharide. Here we report the identification of mRNA for an alternatively spliced form of MD-2, named MD-2B, which lacks the first 54 bases of exon 3. When overexpressed with MD-2, MD-2B competitively suppressed NF-kappaB activity induced by LPS. Regardless of the truncation, however, MD-2B still bound to TLR4 as efficiently as MD-2. Flow cytometric analyses revealed that MD-2B inhibited TLR4 from being expressed on the cell surface. Our data indicate that MD-2B may compete with MD-2 for binding to TLR4 and decrease the number of TLR4/MD-2 complexes on the cell surface, resulting in the inhibition of LPS signaling.