MLR-like reaction between axial organ cells from asterids

Area of Science:

• Marine invertebrate immunology
• Cellular immunology
• Comparative immunology

Background:

• The axial organ (AO) is a key immune component in echinoderms.
• Understanding immune cell interactions in invertebrates is crucial for comparative immunology.
• Previous studies have explored immune responses in various marine organisms.

Purpose of the Study:

• To investigate the immune response of mixed axial organ (AO) cells from two starfish species.
• To compare the efficacy of whole AO cells versus specific subpopulations in eliciting an immune reaction.
• To assess the potential for allogeneic mixed leukocyte reactions in starfish.

Main Methods:

• Culturing mixed axial organ (AO) cells from two starfish species at a 50/50 ratio.
• Utilizing [3H]thymidine uptake to measure cellular proliferation and immune response.
• Employing nylon-wool filtration to isolate nonadherent cell subpopulations.
• Analyzing mixed leukocyte reaction (MLR) outcomes over a five-day culture period.

Main Results:

• A positive mixed leukocyte reaction (MLR) was observed in approximately 20% of mixed AO cell cultures by day five.
• No positive immune response was detected in an allogeneic system.
• The nonadherent nylon-wool subpopulation of AO cells demonstrated more significant immune responses compared to whole AO cells.

Conclusions:

• Starfish axial organ (AO) cells can elicit a measurable immune response when mixed, indicating cellular recognition.
• Nonadherent AO cell subpopulations are more responsive in mixed leukocyte reactions than whole AO cell preparations.
• These findings contribute to understanding immune mechanisms in marine invertebrates and suggest potential for further research into specific immune cell functions.