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Background The influenza virus causes seasonal epidemics which are associated with high morbidity and mortality. Rapid diagnostics tests (RDT) are frequently used to make a quick influenza diagnosis to confirm the clinical suspicion, despite their low sensitivity. Objectives Assess the performance of the Sofia Influenza A+B Fluorescence Immunoassay (Quidel, San Diego, CA). Study design Nasopharyngeal swabs, taken from 241 patients (influenza A (n=73)/B (n=72), negative samples (n=96)) were analyzed using the Sofia Influenza A+B Fluorescence Immunoassay, BinaxNOW Influenza A/B antigen kit (Alere Inc., USA), Directigen EZ Flu A and B (Becton Dickinson, USA), real-time RT-PCR and an influenza virus culture. Results There was a significant difference between the performance of rapid antigen tests and the Sofia FIA, when compared to the RT-PCR, in the detection of influenza strain A and B. Indeed, the Sofia FIA displayed sensitivities of 82.2% and 77.8% for strains A and B respectively, whereas sensitivities of BinaxNOW Influenza A/B antigen kit, and Directigen Flu A and B were 54.8%, and 68.5% for influenza A, and 62.5%, and 52.8% for influenza B respectively. The average RT-PCR threshold cycle (C(t)) (±SD) for the Sofia Influenza A+B Fluorescence Immunoassay-positive specimens was higher than those of the BinaxNOW Influenza A/B antigen and the Directigen EZ Flu A and B kit positive specimens. Conclusion Compared to other RDTs, the Sofia Influenza A+B Fluorescence Immunoassay is a sensitive, and rapid method for the detection and discrimination between influenza A and B.

Summary objective To evaluate 4 rapid malaria diagnostic kits (RDTs) in Korea: OptiMAL test, SD BIOLINEMalaria Ag P.f⁄Pan test, Humasis Malaria P.f⁄Pan antigen test and CareStart Malaria Pf⁄PvCombo test.methods Hundred malaria patients with Plasmodium vivax (P. vivax) and 100 healthy volunteerswere recruited. The results from earlier four RDTs were compared with the reference standard, theGiemsa-stained traditional microscopic diagnosis.results Compared with the reference standard, the sensitivity and specificity for Plasmodium vivaxwere 92.7 and 100% for SD BIOLINE Malaria Ag P.f⁄Pan; and 94.6% and 100% for OptiMAL; 95.5%and 100% for both Humasis Malaria P.f⁄Pan antigen test and CareStart Malaria Pf⁄Pv Combo test.conclusion The performances of all four malaria RDT kits were acceptable, although HumasisMalaria P.f⁄Pan antigen test and CareStartTM Malaria Pf⁄Pv Combo test gave superior performanceswith ROK isolates.keywords Plasmodium vivax, OptiMAL, CareStart, sensitivity, specificityIntroductionPlasmodium vivax (P. vivax) malaria continues to be amajor health problem in the Republic of Korea (ROK),especially near the Demilitarized Zone. Countless effortsagainst malaria have been proposed and launched over thepast three decades. While the spread of P. vivax wasbrought down to manageable levels, malaria transmissionbecame worse in certain locations such as Paju andChulwon. Thus, the overall incidence and prevalence ofmalaria increased (Lim et al. 1999; Lee et al. 2002). Untilrecently, the identification of malarial species dependedupon an expert reading of a Giemsa-stained thin and thickperipheral blood smear. This had many disadvantages, asrelatively few properly trained staff have access to therequired equipment, and rapid and accurate diagnosis ofmalaria are essential to reduce its morbidity and mortality.In 1996, WHO emphasised the urgent need for thedevelopment of simple and cost-effective malaria diagnos-tic tests to overcome the limitations of the clinical diagnosisand accessible light microscopy (WHO Informal Consul-tation on Recent Advances in Diagnostic Techniques andVaccines for Malaria 1996).OptiMAL (DiaMed, Cressier, Switzerland) was the firstrapid malaria test using the immunochromatographymethod (Makler et al. 1998). In the meantime, numerousRDT brands and different products were developed andevaluated for their specificity and sensitivity under differentepidemiological settings and locations, including ROK, asan alternative method to the malaria diagnosis by bloodsmears (Iqbal et al. 2002; Kim et al. 2008; Ashton et al.2010; Cho et al. 2011). WHO and Foundation for Inno-vative New Diagnostics (FIND) evaluated 70 test kits from26 manufacturers (WHO 2008, 2009). The WHO⁄FINDproduct testing of malaria RDTs (WHO 2009, 2010a,b)was the most comprehensive assessment of malaria RDTson the market. However, some field test results showeddiscrepancies to the WHO reports (Ashton et al. 2010).Moreover, some studies indicated that the sensitivity andspecificity of aldolase-based RDT, Binax Now malaria,were not appropriate for the detection of P. vivax in ROK(Cho et al. 2001, 2011).

Cervical cancer caused by human papillomavirus (HPV) might be successfully prevented by HPV vaccination and screening. HPV vaccination and HPV serology assays have been investigated using HPV virus-like particles (VLPs). In this study we produced HPV18 L1 VLPs in Saccharomyces cerevisiae and purified them. The HPV18 L1 gene was cloned into the yeast expression vector YEGalpha-HIR525, and transformed into Saccharomyces cerevisiae. Expression of HPV18 L1 protein was demonstrated by Western blotting. The HPV18 L1 protein was purified by ultracentrifugation, size-exclusion chromatography and cation-exchange chromatography, and was up to 95% pure. We showed by transmission electron microscopy that the purified protein self-assembled into VLPs. These findings should be useful for establishing vaccine efficacy as well as characterizing vaccine candidates, and may provide an international reference standard for HPV serology assays.

Since PvTARAg55 protein (PvTARAg55) of Plasmodium vivax (P. vivax) is expressed during the parasite's sporozoite stage, it was strongly suggested, as a potential candidate for the development of a vaccine against malaria. PvTARAg55 polymorphisms were examined among isolates from various locations in Asian countries mainly; thus the current study could set the valuable baseline data for the development of a vaccine and clinical trials. A total of 59 samples were collected from Asian countries and one isolate from Africa. PvTARAg55 gene from 59 isolates was amplified, sequenced, and analyzed. PvTARAg55 contained a highly conserved tryptophan-rich domain (TRD) and a variable alanine-rich domain (ARD). In comparison to the Sal-1 strain, 10 allelic types of PvTARAg55 were found among 59 isolates. The main observed variations were the insertions and deletions of repeated sequences in the Ala-rich domain. Four types of GGVAAAP repeats were found at codon 324. Interestingly, GGVAAAP was found to be majority of Sal-1 type in the world. Two repeats (x2) were found in isolates from Korea, China, and India. Type of total deletion of GGVAAAP and three repeat (x3) were found from Indonesia isolates. Furthermore, “second insertion repeats” – with one or two repeats – were found with AFGAPSGFAPRP amino acid sequences at codon 338. Two repeats (x2) of AFGAPSGFAPRP were found in Indonesia, and PNG isolates. Finally, a “third repeat” was present with TTVNPEA amino acid sequences at codon 429 (the Indonesian isolates had three TTVNPEA sequences at that position). Isolates from ROK revealed “conserved sequences” in tryptophan-rich domain of PvTARAg55 with single amino acid substitutions (M180I). Hence, the extensive antigenic diversity of PvTARAg55 should be taken in account during the vaccine development.

Nucleotide sequence analyses of the Pvs48/45 and Pvs47 genes were conducted in 46 malaria patients from the Republic of Korea (ROK) (n = 40) and returning travellers from India (n = 3) and Indonesia (n = 3). The domain structures, which were based on cysteine residue position and secondary protein structure, were similar between Plasmodium vivax (Pvs48/45 and Pvs47) and Plasmodium falciparum (Pfs48/45 and Pfs47). In comparison to the Sal-1 reference strain (Pvs48/45, PVX_083235 and Pvs47, PVX_083240), Korean isolates revealed seven polymorphisms (E35K, H211N, K250N, D335Y, A376T, I380T and K418R) in Pvs48/45. These isolates could be divided into five haplotypes with the two major types having frequencies of 47.5% and 20%, respectivelfy. In Pvs47, 10 polymorphisms (F22L, F24L, K27E, D31N, V230I, M233I, E240D, I262T, I273M and A373V) were found and they could be divided into four haplotypes with one major type having a frequency of 75%. The Pvs48/45 isolates from India showed a unique amino acid substitution site (K26R). Compared to the Sal-1 and ROK isolates, the Pvs47 isolates from travellers returning from India and Indonesia had amino acid substitutions (S57T and I262K). The current data may contribute to the development of the malaria transmission-blocking vaccine in future clinical trials.

Fibulin-3, an extracellular glycoprotein, has been suggested as having functions in tissue regeneration and organogenesis. However, its role in cancer remains unclear. We show here that fibulin-3 was silenced by hypermethylation of the promoter region in the relatively invasive A549 non-small cell lung cancer (NSCLC) cells compared with less invasive H460 NSCLC cells. Enforced expression of fibulin-3 in A549 cells down-regulated cellular MMP-7 and MMP-2, which was followed by inhibition of cell invasiveness. Conversely, suppression of fibulin-3 expression with siRNA in H460 cells showed the opposite effect. These results indicate that fibulin-3 is a negative regulator of invasiveness in NSCLC and further studies are needed for its therapeutic applications in treatment of NSCLC.

Phage libraries displaying cDNA or random peptides have been used for profiling autoantibodies in cancer. The detection of autoantibodies in human sera using phages displaying specific epitopes is usually performed by phage-immobilized ELISAs which can detect specific antibodies without identification of whole antigens. However, these ELISAs can give feeble detection signals that are indistinguishable from background signals which are caused by human sera. To improve the usefulness of phage ELISA for human sera, the conditions for each step in phage ELISA were optimized. The antigenicity of phage antigens was maximal when using coating buffer of neutral pH. By using protein-free blocking buffer and pre-adsorbing human sera with phage host cell ER2738 extracts significantly decreased non-specific signals. Finally, when these conditions were applied to phage ELISA using K10P1, the values of the negative controls were concentrated near cutoff values, which made the assay more reliable. The optimized phage ELISA conditions described here would increase the efficacy of detection specific autoantibodies in human sera.

Autoantibodies, which are generated by immune system recognizing the presence of the abnormal tumor-associated antigens, are promising biomarkers for early detection of tumors. Recently, we established a B cell hybridoma pool derived from H-ras12V transgenic mouse, a typical hepatocellular carcinoma model, as a source of tumor-associated autoantibodies without using any extracellular antigens and have characterized the specific target antigens against them. K1 autoantibody, one of them, was investigated in this study and its target antigen was identified by mass spectrometric analysis as fatty acid synthase (FASN), an important oncogenic protein. Moreover, a specific mimotope against K1 autoantibody was screened from the cyclic random hepta-peptide phage library and, using it as a coating antigen for ELISA, we could distinguish patients with hepatocellular carcinoma (HCC) vs. normal subjects with 96.55% sensitivity and 100% specificity. These results imply that anti-FASN autoantibody is induced in patients with HCC and detection of anti-FASN autoantibody can be used for the diagnosis of HCC.

We aimed to determine the prevalence of HPV-16/18 antibodies in Korean women with high-grade cervical intraepithelial neoplasia (CIN) and cervical cancer. We conducted the hospital-based case-control study at the university hospital between 2003 and 2006. Cases were 130 high-grade CIN and 43 cervical cancer patients and the control group was 106 women showing normal cervical cytology. Enzyme-linked immunosorbent assays were performed for HPV-16/18 L1 virus-like particles (VLPs) as an antigen. Seropositivity for HPV-16 VLP and HPV-18 VLP was found in 67.4% and 30.2% of cancer patients and 59.2% and 20.0% of high-grade CIN patients, respectively. Seropositivity for HPV-16 with high-grade CIN (OR 6.91; 95% CI 3.74–12.76) and cervical cancer (OR 8.99; 95% CI 3.88–20.84) presented significant associations, as did seropositivity for HPV-18 (high-grade CIN: OR 3.64; 95% CI 1.67–7.95, cervical cancer: OR 6.82; 95% CI 2.52–18.45). Patients with both HPV-16 and 18 seropositivity were 9.38 times (95% CI 2.98–29.51) more likely to have high-grade CIN and 17.05 times (95% CI 4.55–63.87) more likely to have cancer. Both HPV 16 and 18 L1 VLP serology is the clear disease predictors of presence of high-grade CIN and cervical cancer.