Immunomonitoring of Human Breast Milk Cells During HCMV-Reactivation

Katrin Lazar,Graham Pawelec,Thorsten Kussmann,Rangmar Goelz,Simone Pöschel,Klaus Hamprecht,Kilian Wistuba-Hamprecht

doi:10.3389/fimmu.2021.723010

Abstract

BackgroundBreast milk leukocytes may play a role in protecting the infant from pathogens. The dynamics and the role of lymphocytes in human cytomegalovirus (HCMV)-seropositive mothers shedding HCMV into breast milk during the first months postpartum (p.p.) are mostly unclear.MethodsBreast milk cells were analyzed by Pappenheim panoptic and alpha-naphthyl acetate esterase staining as well as by imaging and polychromatic flow cytometry to simultaneously establish their morphological and phenotypic properties. The latter were characterized in HCMV-seropositive and seronegative mothers´ breast milk cells at different time points p.p.ResultsPanoptic staining of breast milk cells revealed the presence of monocytes/macrophages, granulocytes and lymphocytes. Imaging flow cytometry data combining phenotypic and morphological analysis identified NKT-like cells, NK cells, epithelial cells, T cells and monocytes/macrophages. HCMV-seropositive but not -seronegative mothers had significantly higher T cell frequencies in mature milk.ConclusionsThe presence of lymphocyte subsets in breast milk may be more influenced by the HCMV-seropositivity of the mother than previously recognized.

Highlights

Breast milk is very important for newborns as nutrition and to support their immature immune system [1, 2]
Breast milk cells consist mainly of myo-epithelial cells [6], alveolar epithelial cells defined as lactocytes, stem cells, progenitor cells, monocytes, macrophages, granulocytes, T cells, B cells, NK and NKT-like cells
Breast milk cells were immobilized on microscope slides and either stained panoptically or for a-naphthyl acetate esterase (Figure 1, left and right images respectively)

Summary

Introduction

Breast milk is very important for newborns as nutrition and to support their immature immune system [1, 2]. High percentages of the far identified 976 proteins in milk are involved in immune functions [3, 4]. Oligosaccharides, proteases to cytokines, breast milk is well equipped to defend against pathogens even in the infant’s gut [1, 5]. A potentially important mode of immune support may be the cellular components present in breast milk. Breast milk leukocytes may play a role in protecting the infant from pathogens. The dynamics and the role of lymphocytes in human cytomegalovirus (HCMV)-seropositive mothers shedding HCMV into breast milk during the first months postpartum (p.p.) are mostly unclear

Methods

Results

Conclusion