Related Experiment Video
Updated: Aug 7, 2026
High Throughput Fluorometric Technique for Assessment of Macrophage Phagocytosis and Actin Polymerization
Published on: November 27, 2014
In vitro effects of C-reactive protein on phagocytosis
Insights
C-reactive protein (CRP) enhances the in vitro phagocytosis of bacteria and iron spherules by human leukocytes. This immune-boosting effect was observed when CRP was incubated with leukocytes, but not when added to whole blood.
Area of Science:
- Immunology
- Microbiology
- Biochemistry
Background:
- C-reactive protein (CRP) is a key acute-phase protein involved in the innate immune response.
- Phagocytosis is a critical cellular process for clearing pathogens and cellular debris.
- Understanding factors that modulate phagocytosis is essential for developing immune-boosting strategies.
Purpose of the Study:
- To investigate the in vitro effects of C-reactive protein (CRP) on the phagocytic activity of human leukocytes.
- To determine if CRP can enhance the uptake of various microbial and non-microbial particles by phagocytes.
Main Methods:
- Human leukocytes were isolated from normal blood.
- Particles including carbonyl iron spherules, Diplococcus pneumoniae types IIs and XXVIIs, and Serratia marcescens were used as substrates.
- Leukocytes were incubated with CRP, and phagocytosis was assessed by measuring particle uptake.
Main Results:
- Incubation of leukocytes with CRP significantly increased the rate and number of phagocytosed carbonyl iron spherules, Diplococcus pneumoniae, and Serratia marcescens.
- CRP showed minimal effect on phagocytosis when added to whole blood, except for carbonyl iron spherules.
- Other substances like Escherichia coli lipopolysaccharide and endogenous pyrogen did not stimulate phagocytosis under the tested conditions.
Conclusions:
- C-reactive protein (CRP) possesses in vitro properties that enhance leukocyte phagocytosis of certain microbial and non-microbial particles.
- The observed enhancement of phagocytosis by CRP is dependent on the experimental conditions, particularly the presence of whole blood.
- These findings highlight CRP's potential role in modulating innate immune responses through direct effects on phagocytic cells.
Abstract:
Hokama, Y. (University of California, Los Angeles), Monroe K. Coleman, and Richard F. Riley. In vitro effects of C-reactive protein on phagocytosis. J. Bacteriol. 83:1017-1024. 1962. Carbonyl iron spherules, Diplococcus pneumoniae types IIs and XXVIIs, and Serratia marcescens were phagocytosed more rapidly and in greater numbers by leukocytes of normal human blood after incubation with C-reactive protein. With the exception of carbonyl iron spherules, addition of C-reactive protein to whole blood containing substrate had little effect on the extent of phagocytosis. Normal and acute-phase seromucoid Escherichia coli lipopolysaccharide and crude endogenous pyrogen were without a stimulating effect under the same conditions in the homologous systems employed.
Related Concept Videos
00:41Phagocytosis
The objective of phagocytosis is often destruction. Cells use phagocytosis to eliminate unwelcome visitors, like pathogens (e.g., viruses and bacteria). Many immune system cells, including...
01:17Phagocytosis of Apoptotic Cells
Normal cells contain receptors that prevent them from being recognized by phagocytes.
01:25Immune Surveillance by NK Cells and Phagocytes
Natural Killer Cells: The Fast Responders
NK cells are large granular lymphocytes found in the blood and lymphatic system. These...