Multilaboratory assessment of threshold versus fold-change algorithms for minimizing analytical variability in multiplexed pneumococcal IgG measurements.

Pneumococcal vaccination is frequently used to assess a patient's humoral immune function. The comparison of pre- and postvaccination levels of antipneumococcal antibodies is widely held to be the gold standard for documenting a response. However, many of the published criteria for defining an adequate response are based on assays that are no longer widely available.

Measurement of antibodies to pneumococcal polysaccharides with Luminex xMAP microsphere-based liquid arrays.

The 23 valent pneumococcal polysaccharide vaccine (PPV) is often used to assess an individual's ability to produce antibodies to polysaccharides. The Luminex xMAP microsphere-based liquid array system, when applied to the determination of antibodies to pneumococcal polysaccharides (PnPs), allows for the antibody response to the 23 serotypes to be determined simultaneously. Multiplexing saves considerable time and expense over the traditional method of testing each PnPs serotype individually by the enzyme-linked immunosorbent assay (ELISA).

Elimination of false-positive results in a luminex assay for pneumococcal antibodies.

In our 14-valent Luminex assay for pneumococcal antibodies, we identified two groups of sera that caused false-positive results. The first group bound nonspecifically to the Luminex microspheres. The second group reacted specifically with bovine serum albumin (BSA).

A 22-plex chemiluminescent microarray for pneumococcal antibodies.

We developed a chemiluminescent multiplexed microarray that simultaneously determines IgG antibody concentrations to 22 pneumococcal polysaccharide (PnPs) serotypes (1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 23F, and 33F). We compared the microarray with an enzyme-linked immunosorbent assay (ELISA) for 9 of the 22 serotypes (1, 4, 5, 6B, 9V, 14, 18C, 19F, and 23F). Correlation coefficients (r2) for the comparison of the microarray with ELISA ranged from 0.

Evaluation of a (1->3)-beta-D-glucan assay for diagnosis of invasive fungal infections.

The Fungitell assay (Associates of Cape Cod, Inc.) is a commercial test that detects (1-3)-beta-D-glucan (BG) and is intended for diagnosis of invasive fungal infections. To evaluate the Fungitell assay, we tested serum and plasma samples from healthy blood donors and from patients with blood cultures positive for yeast or bacteria.

Flow cytometric assay for genotyping cytochrome p450 2C9 and 2C19: comparison with a microelectronic DNA array.

Introduction: Cytochrome p450 (CYP) 2C9 and 2C19 metabolize a wide range of therapeutically important drugs. Genetic polymorphisms in the CYP2C9 and CYP2C19 genes result in variations in drug response. To correlate the dose required for therapeutic drug efficacy with genotype, accurate and reliable methods for detecting single nucleotide polymorphisms (SNPs) of CYP2C9 and CYP2C19 are required.

Determination of cytokine responses using a multiplexed fluorescent microsphere immunoassay.

We used a multiplexedfluorescent microsphere immunoassay to develop a sandwich capture assay to assess simultaneously the production of thymus helper (TH) 1- and TH2-type cytokines in tissue culture supernatant obtained from stimulated peripheral blood mononuclear cells. The assay then was used to assess the cytokine production of patients with hyperimmunoglobulinemia E syndrome and in cord blood from neonates. The multiplexed assay has a reportable range of less than 10 to 50,000 pg/mL.

Comparison of a multiplex flow cytometric assay with enzyme-linked immunosorbent assay for auantitation of antibodies to tetanus, diphtheria, and Haemophilus influenzae Type b.

We developed a multiplexed indirect immunofluorescence assay for antibodies to Haemophilus influenza type b (Hib) polysaccharide and the toxoids of Clostridium tetani (Tet) and Corynebacterium diphtheriae (Dip) based on the Luminex multiple-analyte profiling system. A pooled serum standard was calibrated against World Health Organization standards for Dip and Tet and an international standard for Hib. The multiplexed Luminex assay was compared to individual enzyme-linked immunosorbent assays (ELISAs) for the same analytes.

A multiplexed fluorescent microsphere immunoassay for antibodies to pneumococcal capsular polysaccharides.

We developed a multiplexed indirect immunofluorescent assay for antibodies to pneumococcal polysaccharides (PnPs) based on the Luminex multiple analyte profiling system (Luminex, Austin, TX). The assay simultaneously determines serum IgG concentrations to 14 PnPs serotypes: 1, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 12F; 14, 18C, 19F, and 23F. To assess the specificity of the multiplexed assay for each individual serotype, inhibition-of-binding studies were conducted using adult serum samples obtained after pneumococcal vaccination.