Host hindrance to HIV-1 replication in monocytes and macrophages

Monocytes and macrophages are targets of HIV-1 infection and play critical roles in multiple aspects of viral pathogenesis. HIV-1 can replicate in blood monocytes, although only a minor proportion of circulating monocytes harbor viral DNA. Resident macrophages in tissues can be infected and function as viral reservoirs. However, their susceptibility to infection, and their capacity to actively replicate the virus, varies greatly depending on the tissue localization and cytokine environment. The susceptibility of monocytes to HIV-1 infection in vitro depends on their differentiation status. Monocytes are refractory to infection and become permissive upon differentiation into macrophages. In addition, the capacity of monocyte-derived macrophages to sustain viral replication varies between individuals. Host determinants regulate HIV-1 replication in monocytes and macrophages, limiting several steps of the viral life-cycle, from viral entry to virus release. Some host factors responsible for HIV-1 restriction are shared with T lymphocytes, but several anti-viral mechanisms are specific to either monocytes or macrophages. Whilst a number of these mechanisms have been identified in monocytes or in monocyte-derived macrophages in vitro, some of them have also been implicated in the regulation of HIV-1 infection in vivo, in particular in the brain and the lung where macrophages are the main cell type infected by HIV-1. This review focuses on cellular factors that have been reported to interfere with HIV-1 infection in monocytes and macrophages, and examines the evidences supporting their role in vivo, highlighting unique aspects of HIV-1 restriction in these two cell types

Determination of Moisture Levels, Protein and Water Absorption of Chicken Giblets

Abstract This study aimed at evaluating the levels of moisture, protein, water to protein ratio, and water absorption during chilling of chicken giblets (heart, liver, and gizzard) to set legal limits of water absorption during this process. The survey was conducted in the southern Brazil, the largest broiler-producing region of this country. Giblets (heart, liver, and gizzard) were collected fresh from the processing line after evisceration and at the exit of the chiller after the immersion process from two processing plants. One of the plants (PP1) processes small chickens (1,100g live weight) and PP2 processes chickens with 2,800g live weight. In total, 448 samples were collected. Laboratory tests were performed in duplicate for each parameter measured. The results show that moisture levels of fresh giblets were higher in the gizzard, followed by the liver and the heart, whereas in chilled giblets, the gizzard still maintained the highest moisture level, but was followed by the heart and then the liver. Both in fresh and chilled samples, the liver presented the highest protein content, followed by the gizzard and the heart. Water to protein ratios were higher in chilled than in fresh samples, and was highest in the heart, followed by the gizzard and the liver. After immersion in the chiller, the heart presented the highest water absorption rate (6.59%), which was significantly higher compared with those of the liver (4.16%) and the gizzard (4.51%). Considering that the water absorption rates obtained both in fresh and chilled chicken giblets were below 8.00%, the following upper limits of water absorption are suggested for chicken giblet processing in Brazil: 7.0% for the heart, and 5.0% for the gizzard and the liver