Expression of Homing Receptors in IgM⁺IgD⁺CD27⁺ B Cells and Their Frequencies in Appendectomized and/or Tonsillectomized Individuals

ABSTRACT

Background

In humans, blood circulating IgM⁺IgD⁺CD27⁺ B cells are considered analogous to those described in the marginal zone of the spleen and are involved in important immunological processes. The homing receptors they express, and the organs involved in their development (for example, intestinal organs in rabbits) are only partially known. We recently reported that this population is heterogeneous and composed of at least two subsets: one expressing high levels of IgM – IgM^hi B cells – and another low levels – IgM^lo B cells.

Objectives

To evaluate the expression of homing receptors on IgD⁺CD27⁺ IgM^hi and IgM^lo B cells and quantify their frequencies in blood of control and appendectomized and/or tonsillectomized volunteers.

Materials and Methods

Using spectral flow cytometry, the simultaneous expression of 12 previously reported markers that differentiate IgM^hi B cells and IgM^lo B cells and of α4β7, CCR9, CD22 and CCR10 were evaluated in blood circulating B cells of control and appendectomized and/or tonsillectomized volunteers.

Results

The existence of phenotypically defined IgM^lo and IgM^hi B cell subsets was confirmed. They differentially expressed intestinal homing receptors, and the expression of α4β7 and CCR9 seems to determine new IgM subpopulations. IgM^lo and IgM^hi B cells were detected at lower frequencies in the appendectomized and/or tonsillectomized volunteers relative to controls.

Conclusions

Human blood circulating IgD⁺CD27⁺ IgM^lo and IgM^hi B cell subsets differentially express homing receptors, and it is necessary to investigate if mucosal organs are important in their development.

KEYWORDS:

• Appendectomy
• homing receptors
• marginal zone B cells
• spectral flow cytometry
• tonsillectomy

Acknowledgments

We want to thank the volunteers that participated in this study for their generosity, Eugene Butcher for providing α4β7-APC (clon ACT-1), Maria Jaimes for providing antibodies and supervising the flow cytometry experiments, Lorena Chila-Moreno for contributing to the determination of SIgA, and Federico Perdomo for revising the manuscript.

Author contributions

JA, MAF were involved with conceptualization, data curation, funding acquisition, project administration, resources, supervision, writing – original draft, writing – review & editing. DB was involved with conceptualization, data curation, performing the experiments, writing – original draft, writing – review & editing. MCR was involved in experiments to measure SIg, resources, writing – review & editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethics statement

This study was conducted ethically in accordance with the World Medical Association Declaration of Helsinki. This study protocol was reviewed and approved by the ethics committee of the School of Medicine of Pontificia Universidad Javeriana, approval number [0203–19]. Written informed consent approved by the ethics committee of the School of Medicine of Pontificia Universidad Javeriana was obtained from all participants. Data from study volunteers was anonymized. This process did not affect interpretation of the results.

Data availability statement

All data needed to evaluate the conclusions made in this paper are included in the main body of the manuscript. Additional data will be made available by the corresponding author upon reasonable request

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/08820139.2023.2187303.

Additional information

Funding

This project was funded by Pontificia Universidad Javeriana. Diana Bautista was funded by Pontificia Universidad Javeriana. Cytek Biosciences donated the antibodies used for this study. The Asociación Colombiana de Inmunología partially supported the publication fee.