Related Experiment Video
Updated: Jun 25, 2026
Determination of Vaccine Immunogenicity Using Bovine Monocyte-Derived Dendritic Cells
Published on: May 19, 2023
Age related variation in expression of CD21 and CD32 on bovine lymphocytes: a cross-sectional study
Kuldeep S Chattha1, Matthew A Firth, Douglas C Hodgins
1Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario N1G2W1, Canada.
Insights
Neonatal calf immune responses are challenging due to immature immunity and maternal antibodies. This study found that calf B cells express both activating CD21 (complement receptor 2) and inhibitory CD32 (Fc gamma receptor II) from birth, influencing immune function.
Area of Science:
- Veterinary Immunology
- Neonatal Immunology
- B cell Biology
Background:
- Neonatal calves exhibit limited immune responsiveness, hindering active immune responses.
- Maternal antibodies can suppress active immunity in young animals.
- B lymphocytes express CD21 (complement receptor 2) and CD32 (Fc gamma receptor II), which regulate activation and inhibition.
Purpose of the Study:
- To investigate the expression of CD21 and CD32 on B lymphocytes in neonatal calves.
- To determine the role of these receptors in early-life immune function.
- To assess if CD21 expression is a limiting factor for neonatal B cell responses.
Main Methods:
- Cross-sectional study involving 41 Holstein calves (1-90 days old) and 12 mature cows.
- Blood sample analysis using flow cytometry to quantify CD21 and CD32 positive cells.
- Analysis of co-expression of CD21, CD32, and membrane immunoglobulin M (mIgM) on lymphocytes.
Main Results:
- Absolute numbers of CD21+ and CD32+ cells increased from birth to 90 days, with CD21+ cells increasing relatively more.
- Approximately 89% of CD21+ cells also expressed CD32.
- Most circulating B cells (over 92% mIgM+) expressed CD21, but CD21+ cells were not exclusively B cells, indicating CD21 is not a specific B cell marker in calves.
Conclusions:
- Calf B cells express both activating CD21 and inhibitory CD32 receptors from birth.
- The co-expression suggests neonatal B cells are modulated by both activating and inhibitory signals.
- CD21 expression itself does not appear to limit neonatal B cell responses.
Abstract:
It is difficult to induce active immune responses in neonatal calves, partly due to limited functional ability of the immune system and partly due to immune inhibitory effects of maternal antibodies. CD21 (complement receptor 2), an activating receptor, and CD32 (Fc gamma receptor II), an inhibitory receptor, can both be expressed by mature B lymphocytes. Studies of the signalling pathways regulating B cell activation suggest that these receptors have mutually antagonistic effects, that may determine immune responsiveness in the first months of life. In a cross-sectional study, blood was collected from 41 Holstein calves, 1-90 days of age, and 12 mature cows. The absolute number of CD21 and CD32 positive cells increased from birth until 90 days of age, with CD21+ cells showing a greater relative increase compared to CD32+ cells. Approximately 89% of CD21+ cells also expressed CD32. In calves, CD32+ cells consisted of two distinct populations, characterized to be CD14+CD32+IgM(-) (44%) and CD14(-)CD32+IgM+ (53%) cells, consistent with monocytes and B cells respectively. Mean fluorescence intensity (MFI) for CD21 did not change appreciably up to 90 days of age, and mean values were slightly lower than for adults. MFI for CD32 on CD21+ lymphocytes increased slightly over the first 3 months of life, but values were lower than for adults. Over 92% of calf membrane immunoglobulin M+ (mIgM) B cells expressed CD21, however only 60-80% of CD21+ cells were mIgM positive, regardless of age. Although the CD21+IgM(-) cells were not characterized further, it was evident that CD21 is not a suitable surrogate marker for B lymphocytes in calves. Most importantly this study showed that from birth, the majority of circulating B cells express both CD21 and CD32. This suggests that these cells are subject to activating and inhibiting influences mediated by these receptors from birth. Expression of CD21 does not appear to be a limiting factor in neonatal B cell responses.
More Related Videos
07:36Isolation of Human Lymphatic Endothelial Cells by Multi-parameter Fluorescence-activated Cell Sorting
Published on: May 1, 2015
12:53Collection and Processing of Lymph Nodes from Large Animals for RNA Analysis: Preparing for Lymph Node Transcriptomic Studies of Large Animal Species
Published on: May 19, 2018