While mortality and morbidity from pulmonary tuberculosis (PTB) have improved, diagnosis of this infectious disease remains suboptimal without a point-of-care test. Antibody/ antigen-based serodiagnostics is the most amenable for point-of-care translation but hampered by a lack of validated biomarkers and a heterogeneous patient antibody response. Using a case-control design, we assessed serodiagnostic potential of immunoglobulins G, A, and dimeric IgA responses against 18 antigenic preparations, followed by antibody-subclass responses against antigen 60 (A60), and four markers of host innate immunity by enzymelinked immunoassay using sera samples (n=110) collected from April to October 2007 in VietNam from human immunodeficiency-negative patients with provisional diagnosis of PTB. We further analyzed host variables to investigate factors driving biomarker heterogeneity observed in patients. Among active pulmonary tuberculosis patients, low correlation was observed between anti-A60 antibody-classes, and between anti-A60 immunoglobulin G subclasses, but anti-A60 immunoglobulin A subclasses were significantly correlated. The best diagnostic combination of anti-A60 immunoglobulin G/A and a C-reactive protein “ruleout” remains insufficient at 82%/92% sensitivity/specificity (95%CI: 72-92%/82-98%). Heterogeneity of anti-A60 immunoglobulins G2, G3, M, as well as C-reactive protein and serum amyloid A levels observed in this study population appeared to be significantly associated with history of previous tuberculosis, hemoptysis, age, vaccination, night sweats, smoking, chest pain, fever, alcohol, and solid culture count. Further research on tuberculosis serological biomarkers may require consideration of host factors and new approaches using multiple biomarkers.

A putative serine protease of T. spiralis (TsSP) was expressed in Escherichia coli and its potential as a diagnostic antigen was primarily assessed in this study. Anti-Trichinella IgG in serum samples from T. spiralis different animal hosts (mice, rats, pigs and rabbits) were detected on Western blot analysis with rTsSP. Anti-Trichinella antibodies were detected in 100% (30/30) of experimentally infected mice by rTsSP-ELISA. Cross-reactions of rTsSPELISA were not found with sera from mice infected with other parasites (S. erinaceieuropaei, S. japonicum, C. sinensis, A. cantonensis and T. gondii) and sera from normal mice. There was no statistical difference in antibody detection rate among mice infected with the encapsulated Trichinella species (T. spiralis, T. nativa, T. britovi, and T. nelsoni) (P>0.05). The results of rTsSP-ELISA showed that serum specific antibody IgG in mice infected with 100 or 500 T. spiralis muscle larvae (ML) were detectable early at 7-8 dpi, but not detected by ML ES antigen-ELISA prior to 10-12 dpi. Specific anti-Trichinella IgG was detected in 100% (18/18) of infected pigs by rTsSP-ELISA and ES-ELISA, but no specific antibodies was not detected in 20 conventionally raised normal pigs by two antigens. The results showed the rTsSP had the potential for early serodiagnosis of animal Trichinella infection, however it requires to be assayed with early infection sera of swine infected with Trichinella and other parasites.

The purification of parasite-infected erythrocytes from whole blood containing leucocytes is crucial for many downstream genetic and molecular assays in parasitology. Current methodologies to achieve this are often costly and time consuming. Here, we demonstrate the successful application of a cheap and simple Non-Woven Fabric (NWF) filter for the purification of parasitized red blood cells from whole blood. NWF filtration was applied to the malaria-parasitized blood of three strains of mice, and one strain of rat, and to Babesia gibsoni parasitized dog blood. Before and after filtration, the white blood cell (WBC) removal rates and red blood cell (RBC) recovery rates were measured. After NWF filter treatment of rodent malaria-infected blood, the WBC removal rates and RBC recovery rates were, for Kunming mice: 99.51%±0.30% and 86.12%±8.37%; for BALB/C mice: 99.61%±0.15% and 80.74%±7.11%; for C57 mice: 99.71%±0.12% and 84.87%±3.83%; for Sprague-Dawley rats: 99.93%±0.03% and 83.30%±2.96%. Microscopy showed WBCs were efficiently removed from infected dog blood samples, and there was no obvious morphological change of B. gibsoni parasites. NWF filters efficiently remove leukocytes from malaria parasite-infected mouse and rat blood, and are also suitable for filtration of B. gibsoni-infected dog blood.