Screening the B- and T-cell epitope map of TP0136 and exploring their effect in a Treponema pallidum rabbit model.

The systemic immune response, including B- and T-cell reactions, plays a corresponding role in syphilis infections. The TP0136 protein is a target of the immune response in infected hosts and may mediate the immune response. Here, we developed a method that combining reverse vaccine approach with Pepscan/T-cell proliferation to screen and identify three B-cell and two T-cell epitopes of TP0136, and explore the role of the B- and T-cell epitopes in immunized-infected animals. The results showed that immunized with B-cell epitopes not only had no protective effect but also aggravated the syphilitic lesion development. While immunized with T-cell epitopes of TP0136 could induce a strong Th1-cellular immunity response, which could attenuate syphilitic lesion development to a certain extent. The variation in exacerbation or attenuation of skin lesions, induced by distinct B- and T-cell epitopes of Tp0136, within the host's defense against syphilis warrants in-depth exploration.

Association between treatment failure in patients with early syphilis and penicillin resistance-related gene mutations of Treponema pallidum: Protocol for a multicentre nested case-control study.

Background: The widespread occurrence of syphilis remains a global public health problem. Although penicillin has been recommended as the first-line therapy for syphilis for more than 70 years, treatment failure occurs in 10-20% of patients with early syphilis. Recent studies have reported varied single-nucleotide polymorphisms (SNPs) of Treponema pallidum related to penicillin resistance. The clinical relevance of these SNPs to treatment failure in patients with early syphilis is unresolved. In this work, a protocol is developed to evaluate the association between treatment failure in patients with early syphilis and penicillin resistance-related gene mutations of T. pallidum. Methods: A multicentre nested case-control study is designed, and patients who are diagnosed with early syphilis and treated with penicillin will be recruited for the study cohort. Before the first treatment, baseline information and biological specimens will be collected from the subjects, and serological tests for syphilis will be performed. Each participant will be followed up at 1, 3, 6, 9, and 12 months after the first treatment, and the clinical manifestations and serum non-treponemal test titres will be evaluated at each follow-up. Patients who will fail treatment are defined as cases, and those who will respond to treatment are defined as controls. Tests for SNPs related to penicillin-binding proteins and Tp47 will be performed in these cases and controls. Survival analysis is used performed to identify gene mutations of T. pallidum related to penicillin resistance and their combinations associated with treatment failure. Discussion: This protocol provides a practical clinical study design that illustrates the role of gene mutations of T. pallidum related to penicillin resistance in the treatment outcome of patients with early syphilis.

Serum Ubiquitin C-Terminal Hydrolase-L1, Glial Fibrillary Acidic Protein, and Neurofilament Light Chain Are Good Entry Points and Biomarker Candidates for Neurosyphilis Diagnosis Among Patients Without Human Immunodeficiency Virus to Avoid Lumbar Puncture.

BACKGROUND: Laboratory tests to diagnose neurosyphilis using cerebrospinal fluid (CSF) are currently disadvantageous as a lumbar puncture is required, which may result in patients with neurosyphilis missing an opportunity for early diagnosis. Thus, blood biomarker candidates that are more convenient and minimally invasive to collect for diagnosing neurosyphilis is urgently needed. METHODS: This observational study aimed to analyze serum ubiquitin C-terminal hydrolase-L1 (UCH-L1), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NF-L) levels in 153 patients without human immunodeficiency virus (HIV) and to evaluate their diagnostic performance in neurosyphilis compared with CSF. RESULTS: Serum UCH-L1, GFAP, and NF-L levels were significantly higher in patients with neurosyphilis compared with patients with uncomplicated syphilis or non-syphilis. For the diagnosis of neurosyphilis, serum UCH-L1, GFAP, and NF-L revealed sensitivities of 90.20%, 80.40%, and 88.24%, and specificities of 92.16%, 78.43%, and 80.39%, respectively, at cutoff levels of 814.50 pg/mL, 442.70 pg/mL, and 45.19 pg/mL, respectively. In patients with syphilis, serum UCH-L1, GFAP, and NF-L levels correlated strongly or moderately with those in the CSF, with similar or better diagnostic performance than those in the CSF. The testing algorithms' sensitivity and specificity increased to 98.04% and 96.08%, respectively, when subjected to parallel and combination testing, respectively. CONCLUSIONS: To avoid lumbar puncture, each serum UCH-L1, GFAP, and NF-L is a good entry point and biomarker candidate for the diagnosis of neurosyphilis among patients without HIV. These proteins used in concerto can further improve the diagnostic sensitivity and specificity.

Evaluation of cerebrospinal fluid ubiquitin C-terminal hydrolase-L1, glial fibrillary acidic protein, and neurofilament light protein as novel markers for the diagnosis of neurosyphilis among HIV-negative patients.

OBJECTIVES: To evaluate the possibility of using cerebrospinal fluid (CSF) ubiquitin C-terminal hydrolase L1 (UCH-L1), glial fibrillary acidic protein (GFAP), and neurofilament light protein (NF-L) for the diagnosis of neurosyphilis (NS). METHODS: A cross-sectional study of 576 subjects was conducted at Zhongshan Hospital from January 2021 to August 2022 to evaluate the diagnostic accuracy of CSF UCH-L1, GFAP, and NF-L for NS and analyze their correlations with CSF rapid plasma reagin (RPR), white blood cells (WBCs), and protein. RESULTS: Patients with NS had higher CSF UCH-L1, GFAP, and NF-L levels than patients with syphilis/non-NS and nonsyphilis. Using a cut-off point of 652.25 pg/ml, 548.89 pg/ml, and 48.38 pg/ml, CSF UCH-L1, GFAP, and NF-L had a sensitivity of 85.11%, 76.60%, and 82.98%, with a specificity of 92.22%, 85.56%, and 91.11%, respectively, for NS diagnosis. Moreover, parallel and serial testing algorithms improved their sensitivity and specificity to 93.62% and 98.89%, respectively. Interestingly, levels between patients with NS who are CSF RPR-positive and -negative did not differ and showed a weak or moderate correlation with WBC and CSF protein in patients with syphilis. CONCLUSION: CSF UCH-L1, GFAP, and NF-L can be used as novel markers for the diagnosis of NS, independent of CSF RPR, WBC, and proteins.

Community engagement on-site rapid test for chlamydia and gonorrhea among men who have sex with men: a pioneering study in Guangzhou, China.

BACKGROUND: Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections are prevalent among men who have sex with men (MSM) in China. However, compared to syphilis and HIV, the testing rate for chlamydia and gonorrhea remains low. The purpose of this pilot study was to evaluate the feasibility for conducting rapid nucleic acid test for chlamydia and gonorrhea in MSM community-based organizations (CBO). METHOD: We recruited our participants through an MSM CBO where free HV and syphilis testing were routinely provided. We collected data including social-demographic background, sexual history, chlamydia and gonorrhea testing history, and reasons for accepting this on-site rapid testing. Urine and/or anorectal swab samples were collected and tested for chlamydia and gonorrhea on-site and the testing results were delivered in about 1.5 h. Positive cases received on-site free treatment. RESULTS: From August 2020 to October 2020, 634 MSM visited the CBO for syphilis and HIV testing and 158 (158/634, 24.9%) accepted the on-site chlamydia and gonorrhea rapid test, 135 were finally enrolled. The positive rate fo chlamydia was 16.3% (22/135) and 3.0% (4/135) for gonorrhea, respectively. Only 19.3% participants had previously undergone chlamydia and gonorrhea testing and 68.9% (93/135) participants reported that they had heard of gonorrhea, 47.4% (64/135) had heard of chlamydia. The main reason for testing was "free for charge" (66.2%), followed by "convenient, 'shorter waiting time" (45.2%) and "had high-risk sexual behavior recently" (16.3%). CONCLUSIONS: This pilot study showed that the chlamydia and gonorrhea infection rate remains high among MSM, while the testing rate was low. On-site rapid testing is feasible and potentially preferred by MSM.

Prevalence and correlates of Mycoplasma genitalium infection among patients attending a sexually transmitted infection clinic in Guangdong, China: a cross-sectional study.

BACKGROUND: Mycoplasma genitalium (MG) causes urogenital tract infections and is associated with reproductive morbidity. Although MG has been reported across many regions and population groups, it is not yet routinely tested for in China. Our study contributes to current research by reporting the prevalence and correlates of MG infection in patients attending a sexually transmitted infection (STI) clinic in Guangdong from Jan 2017-May 2018. METHODS: Urethral (from 489 men) and endo-cervical (from 189 women) samples, blood samples, and patient histories (via questionnaires) were collected. Doctors clinically diagnosed anogenital warts (GW) during the examination (n = 678). The presence of MG was evaluated using an in-house via polymerase chain reaction protocol. We also tested all participants for herpes simplex virus-2 (HSV-2), Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT), syphilis and HIV. Univariate and multivariate logistic regression were used to evaluate factors associated with MG. RESULTS: MG was detected in 7.2% (49/678) of the patients (men, 7.4%; women, 6.9%). The MG positivity rate was 14.2% among symptomatic patients, and 5.6% for asymptomatic patients, respectively. Only 36.7% (18/49) Mg positive patients were symptomatic. Among the MG-infected patients, 10.2% were co-infected with CT, 6.1% with NG, 8.2% with HSV-2, 4.1% with syphilis and 22.4% with GW. Presentation with clinical symptoms was significantly associated with MG infection [OR = 2.52 (2.03-3.13)]. In our analysis, MG was not associated with other STIs. CONCLUSIONS: MG is a relatively common infection among individuals attending an STI clinic in Guangdong Province. Routine testing of symptomatic patients may be necessary, and more epidemiological studies are needed to provide evidence for future testing guidelines.

Tp0136 targets fibronectin (RGD)/Integrin ß1 interactions promoting human microvascular endothelial cell migration.

Lesion healing without treatment is a unique clinical characteristic of the early stages of syphilis infection. Angiogenesis, which involves endothelial cell migration, is an important process in wound healing. Tp0136, an outer membrane protein of T. pallidum, has the ability to bind host fibronectin-producing cells, which plays a crucial role in the pathogenesis of syphilis. In this research, we purposed to analyze the role of Tp0136 in the migration of human microvascular endothelial (HMEC-1) cells and to explore the related mechanism. First, Tp0136 significantly promoted HMEC-1 cell migration. Furthermore, the levels of C-C motif ligand 2 (CCL2) mRNA and protein expression rose with the concentration and time increasing of Tp0136. The migration of HMEC-1 cells was significantly suppressed by an anti-CCL2 antibody and a CCR2 (the CCL2 receptor) inhibitor. Further study revealed that, in cells pretreated with anti-fibronectin antibody, anti-integrin ß1 antibody or RGD (Arg-Gly-Asp), the expression levels of CCL2 induced by Tp0136 were notably decreased. Additionally, after pretreatment with an anti-fibronectin antibody, an anti-integrin ß1 antibody or RGD, the migration of HMEC-1 cells treated with Tp0136 was obviously suppressed. These results show that Tp0136 promots the migration of HMEC-1 cells by inducing CCL2 expression via the interaction of the fibronectin RGD domain with integrin ß1 and the CCL2/CCR2 signaling pathway, and these interactions may contribute to the mechanisms that increase the capacity for self-healing syphilis infection.

Gonorrhea and chlamydia prevalence in different anatomical sites among men who have sex with men: a cross-sectional study in Guangzhou, China.

BACKGROUND: A high rectal and oropharyngeal sexually transmitted infection (STI) burden has been reported among men who have sex with men (MSM) in many regions, but little data exists on rectal and oropharyngeal STIs among MSM in China. The purpose of this study was to determine the prevalence of gonorrhea and chlamydia at different anatomic sites among MSM in Guangzhou, China. METHODS: We recruited a cross-sectional sample of MSM in one Chinese city and collected detailed information about socio-demographic characteristics and sexual behaviors. Men had urine, rectal, and pharyngeal swab samples tested for gonorrhea and chlamydia using nucleic acid amplification tests (NAAT). Univariate and multivariate logistic regressions were used to evaluate factors associated with gonorrhea and chlamydia. Among men without any STI symptoms, we also examined the prevalence of gonorrhea and chlamydia by anatomical site. RESULTS: We enrolled 463 men between January 2015 and March 2017. A total of 58/463 (12.5%) of men had gonorrhea and 84/463 (18.1%) had chlamydia. MSM with gonorrhea were more likely to have been recruited from the STI clinic (OR 3.41, 95% CI 1.94-5.99), living with HIV (OR 2.41, 95% CI 1.18-4.92), diagnosed had STI co-infection (OR 2.55, 95% CI 1.39-4.69). MSM with chlamydia were more likely to be students (OR 1.8, 95% CI 0.99-3.39). Most gonorrhea (34/58, 59%) and chlamydia (64/84, 76%) infections were not associated with STI symptoms. CONCLUSION: Asymptomatic gonorrhea and chlamydia infection were common in this sample of Chinese MSM. Further research is necessary to determine optimal STI screening programs.

Cytokines in cerebrospinal fluid of neurosyphilis patients: Identification of Urokinase plasminogen activator using antibody microarrays.

Little is known regarding protein responses to syphilis infection in cerebrospinal fluid (CSF) of patients presenting with neurosyphilis. Protein and antibody arrays offer a new opportunity to gain insights into global protein expression profiles in these patients. Here we obtained CSF samples from 46 syphilis patients, 25 of which diagnosed as having central nervous system involvement based on clinical and laboratory findings. The CSF samples were then analyzed using a RayBioH L-Series 507 Antibody Array system designed to simultaneously analyze 507 specific cytokines. The results indicated that 41 molecules showed higher levels in patients with neurosyphilis in comparison with patients without neural involvement. For validation by single target ELISA, we selected five of them (MIP-1a, I-TAC/CXCL11, Urokinase plasminogen activator [uPA], and Oncostatin M) because they have previously been found to be involved in central nervous system (CNS) disorders. The ELISA tests confirmed that uPA levels were significantly higher in the CSF of neurosyphilis patients (109.1±7.88pg/ml) versus patients without CNS involvement (63.86±4.53pg/ml, p<0.0001). There was also a clear correlation between CSF uPA levels and CSF protein levels (p=0.0128) as well as CSF-VDRL titers (p=0.0074) used to diagnose neurosyphilis. No significant difference between the two groups of patients, however, was found in uPA levels in the serum, suggesting specific activation of the inflammatory system in the CNS but not the periphery in neurosyphilis patients. We conclude that measurements of uPA levels in CSF may be an additional parameter for diagnosing neurosyphilis.