Dendritic cell TLR4 induces Th1-type immune response against Cryptosporidium parvum infection

The objective of this study was to investigate the mechanism of Toll-like receptor (TLR4)- mediated dendritic cell (DC) immune against Cryptosporidium parvum infection. C. parvum sporozoites were labeled with 5,6-carboxyfluorescein diacetate succinimidyl ester. Murine bone marrow-derived DCs were isolated, and divided into TLR4 antibody blocking (TAB; infected with 2 × 10⁵ labeled sporozoites and 0.5 μg TLR4 blocking antibody), TLR4 antibody unblocking (TAU; infected with 2 × 10⁵ labeled sporozoites), and blank control (BC; with 1.5 mL Roswell Park Memorial Institute 1640 medium) groups. The adhesion of Cryptosporidium sporozoites to DCs and CD11c⁺ levels were examined by fluorescence microscopy and flow cytometry. Male KM mice were orally injected with C. parvum. The proliferation of T lymphocytes in spleen, expression of cytokines in peripheral blood, and TLR4 distribution features in different organs were further determined by immunohistochemistry. A significantly higher expression of CD11c⁺ and higher C. parvum sporozoite adhesion were found in the TAU group compared with other groups. The expression of CD4⁺CD8^- /CD8⁺CD4^- in the spleen were obviously differences between the TAB and TAU groups. The expression of TLR4, interleukin IL-4, IL-12, IL-18 and IFN-γ improved in the TAU group compared with TAB group. Higher expression of TLR4 was detected in the lymph nodes of mice in the TAU group, with pathological changes in the small intestine. Hence, TLR4 could mediate DCs to recognize C. parvum, inducing Th1 immune reaction to control C. parvum infection.

Genome re-sequencing to identify single nucleotide polymorphism markers for muscle color traits in broiler chickens

OBJECTIVE

Meat quality including muscle color in chickens is an important trait and continuous selective pressures for fast growth and high yield have negatively impacted this trait. This study was conducted to investigate genetic variations responsible for regulating muscle color.

METHODS

Whole genome re-sequencing analysis using Illumina HiSeq paired end read method was performed with pooled DNA samples isolated from two broiler chicken lines divergently selected for muscle color (high muscle color [HMC] and low muscle color [LMC]) along with their random bred control line (RAN). Sequencing read data was aligned to the chicken reference genome sequence for Red Jungle Fowl (Galgal4) using reference based genome alignment with NGen program of the Lasergene software package. The potential causal single nucleotide polymorphisms (SNPs) showing non-synonymous changes in coding DNA sequence regions were chosen in each line. Bioinformatic analyses to interpret functions of genes retaining SNPs were performed using the ingenuity pathways analysis (IPA).

RESULTS

Millions of SNPs were identified and totally 2,884 SNPs (1,307 for HMC and 1,577 for LMC) showing >75% SNP rates could induce non-synonymous mutations in amino acid sequences. Of those, SNPs showing over 10 read depths yielded 15 more reliable SNPs including 1 for HMC and 14 for LMC. The IPA analyses suggested that meat color in chickens appeared to be associated with chromosomal DNA stability, the functions of ubiquitylation (UBC) and quality and quantity of various subtypes of collagens.

CONCLUSION

In this study, various potential genetic markers showing amino acid changes were identified in differential meat color lines, that can be used for further animal selection strategy.