Comparison of pro-inflammatory cytokines (IL-6, IL-1α and IL-1β) released by MPI and MARCO (-/-) knockout cells when stimulated by heat killed fungi- Candida albicans and Aspergillus niger

Abstract

Background: Alveolar Macrophages serve the first line of defence against invading pathogens within the lungs. During the innate immune response, they recognise pathogens such as Candida albicans and Aspergillus niger as “non-self”, phagocytosing them before the pathogen can infiltrate the body and cause disease. There are many Pattern Recognition Receptors (PRRs) that detect specific patterns on the pathogen (PAMPs), inducing an immune response which recruits different immune cells to the site of infection, releasing many cytokines that help with recruiting and clearance of the pathogen. MARCO is a Scavenger receptor that has an important role in the recognition and response mechanisms and this experiment was carried out to confirm the role of MARCO receptors on MPI cells stimulated with heat killed fungi.

Method: MPI cells were cultured, exposed to different concentrations of C.albicans, A.niger and Beta-glucan over a period of 16-18 hours and then quantified using ELISA. The cytokines measured were IL-6, IL-1α and IL-1β. The same procedures were carried out on MARCO-/- MPI cells too.

Results: The results show a significant difference in the amount of pro-inflammatory cytokines produced compared to the control, demonstrating that the immune response was instigated.

MARCO-/- cells showed no immune response compared to the control. They were also compared to the normally stimulated MPI cells.

Conclusion: The study consolidates the importance of the MARCO receptor in response to pathogens.