Repertoire-Based Diagnostics Using Statistical Biophysics

A fundamental challenge in immunology is diagnostic classification based on repertoire sequence. We used the principle of maximum entropy (MaxEnt) to build compact representations of antibody (IgH) and T-cell receptor (TCRβ) CDR3 repertoires based on the statistical biophysical patterns latent in the frequency and ordering of repertoires’ constituent amino acids. This approach results in substantial advantages in quality, dimensionality, and training speed compared to MaxEnt models based solely on the standard 20-letter amino-acid alphabet. Descriptor-based models learn patterns that pure amino-acid-based models cannot. We demonstrate the utility of descriptor models by successfully classifying influenza vaccination status (AUC=0.97, p=4×10-3), requiring only 31 samples from 14 individuals. Descriptor-based MaxEnt modeling is a powerful new method for dissecting, encoding, and classifying complex repertoires.

The Biological Effect of Iron Oxide and Its Hydrate Nanoparticles

Iron oxide and its hydrate nanoparticles were synthesized by hydrothermal method and confirmed by infrared and SEM (Scanning Electron Microscope) et al. The dimensions of the nanoparticles are about 50-120 nm. The crystalline form of iron oxide nanoparticles is like globosity while its hydrate rod. Amino acids intermingling with the synthesized nanoparticles were crystallized to investigate the space effect of the nanoparticles. The crystalline forms of crystal are different to that of pure amino acid. The positions and width of the nanoparticles’ peaks in the infrared spectrum are changed too. Microscope observation and infrared spectrum results indicated the nanoparticles had changed the internal structure of amino acids crystal. To considerate the toxicity of the synthesized nanoparticles, MTT (3-(4,5-dimethylthiazol 2-yl)-2,5 diphenyltetrazolium bromide) assay was used to determine their cytotoxicity. The OD value (Optical Density) was used to calculated RGR% (Relative Generation Rate) of cells, which determined the grade of cytotoxicity. The RGR of nanoparticles of iron oxide and its hydrate are about 1 to 2, which indicate they have just low toxicity.