Related Experiment Video
Updated: Aug 12, 2026
08:03
A Tandem Liquid Chromatography–Mass Spectrometry-based Approach for Metabolite Analysis of Staphylococcus aureus
Published on: March 28, 2017
Modulation of mitogenic responsiveness by staphylococcal peptidoglycan
Infection and Immunity
|November 1, 1980
Summary
Staphylococcal peptidoglycan enhances mouse splenocyte responses to certain mitogens like phytohemagglutinin but reduces responses to lipopolysaccharide. These effects are mediated by B lymphocytes and persist for weeks.
Area of Science:
- Immunology
- Microbiology
Background:
- Staphylococcal peptidoglycan is known to influence antibody production and act as a B-cell mitogen.
- Understanding how peptidoglycan affects immune cell responses is crucial for developing immunomodulatory strategies.
Purpose of the Study:
- To investigate the impact of in vivo peptidoglycan administration on the subsequent in vitro mitogenic responsiveness of mouse splenocytes.
- To determine the specific effects on responses to phytohemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM), and lipopolysaccharide (LPS).
Main Methods:
- Mice were injected with peptidoglycan, and their splenocytes were subsequently isolated.
- Splenocyte deoxyribonucleic acid (DNA) synthesis was measured in vitro in response to various mitogens (PHA, Con A, PWM, LPS).
- Cell separation techniques were employed to identify the immune cells mediating the observed effects.
Main Results:
- Peptidoglycan injection significantly increased splenocyte responsiveness to PHA (100%) and PWM (100%), and moderately increased responsiveness to Con A (45%).
- Conversely, responsiveness to LPS was decreased by 40% following peptidoglycan treatment.
- The observed modulations in mitogenic response were found to be mediated by B lymphocytes.
Conclusions:
- In vivo administration of staphylococcal peptidoglycan alters the mitogenic responsiveness of mouse splenocytes, enhancing responses to some T-cell dependent mitogens while suppressing responses to a T-cell independent mitogen.
- B lymphocytes play a key role in mediating these peptidoglycan-induced immunomodulatory effects.
Related Concept Videos
02:38Mitogens and the Cell Cycle
Mitogens and their receptors play a crucial role in controlling the progression of the cell cycle. However, the loss of mitogenic control over cell division leads to tumor formation. Therefore, mitogens and mitogen receptors play an important role in cancer research. For instance, the epidermal growth factor (EGF) - a type of mitogen and its transmembrane receptor (EGFR), decides the fate of the cell's proliferation. When EGF binds to EGFR, a member of the ErbB family of tyrosine kinase...
01:28Peptidoglycan Synthesis
Structure of PeptidoglycanPeptidoglycan is a vital structural component of the bacterial cell wall, providing mechanical strength and shape to the cell. It consists of repeating units of two sugars—N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)—linked by β-1,4 glycosidic bonds. These sugar chains are cross-linked by short peptide chains, forming a mesh-like polymer that surrounds the bacterial plasma membrane.Cytoplasmic Phase – Precursor SynthesisPeptidoglycan biosynthesis begins in...
01:17Gene Regulation During Sporulation
Sporulation is a complex developmental process that allows certain Gram-positive bacteria, such as Bacillus subtilis and Clostridium species, to survive extreme environmental conditions. This process is tightly regulated by a series of signaling cascades and transcriptional controls, ensuring the formation of a highly resistant endospore.Sporulation is triggered by unfavorable conditions, such as nutrient depletion, and is governed by a phosphorelay system. One of the sensor kinases, such as...
01:23Stringent Response in E. coli
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
01:30Other Stress Responses in Bacteria
Bacteria have global regulatory systems that control several types of stress mechanisms. These include Pho regulon and the heat shock response, which are essential systems for environmental adaptation, such as nutrient limitation and proteotoxic stress. The Pho regulon and the heat shock response exemplify bacterial resilience, enabling rapid adaptation to fluctuating environmental conditions.Pho RegulonBacteria require phosphorus for essential cellular processes, including nucleic acid...
01:28Regulation of Bacterial Virulence
Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...