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Updated: Aug 8, 2026
Isolation and Flow Cytometric Characterization of Murine Small Intestinal Lymphocytes
Published on: May 8, 2016
Histological enzyme and flow cytometric analysis of channel catfish intestinal tract immune cells
Pamela Hébert1, A Jerald Ainsworth, Bobbie Boyd
1College of Veterinary Medicine, Mississippi State University, PO Box 9825, Mississippi State, MS 39762, USA. pheber@lsuhsc.edu
Insights
Channel catfish gastrointestinal tract immunity relies on innate responses, with few B lymphocytes but abundant neutrophils and macrophages, suggesting a unique immune strategy in this fish species.
Area of Science:
- Immunology
- Fish Biology
- Aquaculture
Background:
- The gastrointestinal tract (GIT) is a critical interface for nutrient absorption and pathogen defense in fish.
- Understanding the immune cell populations within the GIT is essential for assessing mucosal immunity.
- Channel catfish (Ictalurus punctatus) are a significant aquaculture species, making their immune responses of economic importance.
Purpose of the Study:
- To characterize the leukocyte populations in the gastrointestinal tract of channel catfish.
- To investigate the distribution and types of immune cells within the catfish GIT.
- To infer the primary mechanisms of mucosal immunity in channel catfish.
Main Methods:
- Leukocytes were isolated from the lamina propria of the channel catfish GIT using collagenase digestion.
- Flow cytometry was employed to quantify different leukocyte populations, specifically B lymphocytes.
- Histochemistry and enzyme staining techniques were utilized to identify and localize various immune cells, including neutrophils, macrophages, and T lymphocytes, within the GIT tissue.
Main Results:
- Flow cytometry revealed that GIT leukocytes were predominantly neutrophils, with B lymphocytes comprising less than 6% of the cell population.
- Histochemical and enzyme staining confirmed a high prevalence of neutrophils and macrophages throughout the GIT.
- T lymphocytes were also observed distributed across the gastrointestinal tract, while B lymphocytes remained scarce.
Conclusions:
- The channel catfish GIT exhibits a distinct leukocyte profile, characterized by a dominance of innate immune cells like neutrophils and macrophages.
- The limited presence of adaptive immune cells (B lymphocytes) suggests a reduced role for specific immunity in this fish's intestinal defense.
- Channel catfish may depend more significantly on a robust innate immune system for intestinal mucosal immunity compared to other studied teleost species.
Abstract:
Channel catfish, Ictalurus punctatus, gastrointestinal tract leukocytes were characterized using flow cytometry, histochemistry, and enzyme staining techniques. Cells obtained from the lamina propria by collagenase digestion were found to be primarily neutrophils, with fewer than 6% B lymphocytes as determined by flow cytometry. Histochemical and enzyme stains were used to determine leukocyte distribution in gastrointestinal tract tissue. Macrophages and T lymphocytes were observed throughout the gastrointestinal tract. As in flow cytometry studies, few B lymphocytes and many neutrophils were observed in the channel catfish gastrointestinal tract. Since cells involved in specific immunity appear to be limited in gastrointestinal tract tissue of channel catfish, we speculate that catfish may rely more heavily on a highly developed innate response for intestinal mucosal immunity than other teleost species studied.
