The human immune system consists of various mechanisms, both innate and acquired, which work to protect against infectious diseases. These mechanisms are composed of cellular and humoral elements free in body fluids and serum. Adaptive mechanisms often combine with innate mechanisms to produce many desired effects.
NK cells are a major immune system component, and their role in the body's defense is vital for overall health and wellness. These cells are activated by various signals that have a diverse influence on their activity. These signals include cytokines, chemokines, and adhesion molecules. NK cells are activated by a combination of these signals and receptors.
NK cells are sentinels of the immune system, constantly scanning the cellular environment for imbalances. They respond to either inhibitory or activating signals and have a role in fighting bacterial infections. Inflammatory disorders are also reduced as NK cells destroy inflamed cells.
NK cells originate in the bone marrow and are present throughout the body. They express specific surface markers and perform specific functions. These cells also contribute to contact hypersensitivity and memory-type immune responses. However, the precise mechanism by which NK cells initiate these responses is still unknown.
The immune system uses a series of adaptive mechanisms to respond to foreign antigens. Some of these mechanisms only act against specific antigens, and others work against a broad range of antigens. Most of these mechanisms act via interactions between the T-cells and the complement system, while others function directly against the antigen. The key feature of these immune systems is that they often trigger inflammation, which can be acute or chronic.
The adaptive immune response relies on B and T cells. Activated B and T cells multiply to attack the pathogen by directly killing it or secreting antibodies that enhance phagocytosis. This process involves memory, and it takes a long time for the immune cells to identify and activate the foreign antigen.
Using the CRISPR-Cas immune system, microbes can silence the genetic messages of invaders and acquire immunity from future attacks. But scientists have long wondered how CRISPR's customized small RNA molecules get produced. Fortunately, a recent study by researchers at UC Berkeley Lab provides some answers.
The researchers sequenced 70 C. sakazakii strains, representing four major pathovars of the pathogen. They grouped the isolates based on their CRISPR-cas gene content and compared closely related and unrelated strains. This allowed for a thorough analysis of the CRISPR-Cas loci of C. sakazakii, which is responsible for neonatal meningitis.
In this study, scientists mapped the CRISPR-Cas loci in a laboratory model of C. sakazakii, a type I-E bacterium. Their data suggested that CRISPR-Cas can adapt to environmental conditions and exposures. But the CRISPR-Cas immune system was still remarkably inefficient compared to other innate immune systems.