Neutrophil progenitor populations of rhesus macaques

Abstract

Captive-bred rhesus macaques of Indian origin represent one of the most important large animal models for infectious disease, solid organ transplantation and stem cell research. There is a dearth of information defining hematopoietic development, including neutrophil leukocyte differentiation in this species using multicolor flow cytometry. In the current study we sought to identify cell surface markers that delineate neutrophil progenitor populations with characteristic immunophenotypes. We defined four different post-mitotic populations based on their CD11b and CD87 expression pattern, and further refined their immunophenotypes using CD32, CD64, lactoferrin and myeloperoxidase as antigenic markers. The four subsets contained myelocyte, metamyelocyte, band, and segmented neutrophil populations. We compared our flow cytometry-based classification with the classical nuclear morphology-based classification. We found overlap of immunological phenotype between populations of different nuclear morphology and identified phenotypically different subsets within populations of similar nuclear morphology. We assessed the responsiveness of these populations to stimulatory signals such as LPS, fMPL or PMA, and demonstrated significant differences between human and rhesus macaque neutrophil progenitors. In this study we provided evidence for species-specific features of granulopoiesis that ultimately manifested in the divergent immunophenotypes of the fully differentiated segmented neutrophils of humans and rhesus macaques. Additionally, we found functional markers that can be used to accurately quantify neutrophil progenitors by flow cytometry. While these markers do not coincide with the classical nuclear-morphology-based grading they enable us to perform functional studies monitoring immunophenotypic markers.

What Is the Evolutionary Fingerprint in Neutrophil Granulocytes?

“…CXCR4 ensures the maintenance of neutrophils within the bone marrow, while binding of CXCR2, G-CSF receptors, or Toll-like receptors trigger their release [62,63]. While human neutrophils completely mature inside the bone marrow, there are indications for a completion of maturation outside the bone marrow in mice [64] and rhesus macaques [65].…”

“…This has recently been reviewed by van Rees et al [196] comparing mice and humans. Differences arise even in as closely related beings as nonhuman primates and humans, moreover between the distinct primate species [65]. A familiar example for species specificity is the fMLP receptor, present with one or two subtypes in some animals.…”

Systemic and mucosal mobilization of granulocyte subsets during lentivirus infection

“…Granulocytes play major roles as innate immune cells against bacterial, viral and parasitic pathogens which have been described in multiple studies (11,19,24,33,38,39). Their protective role against HIV as well as their pathogenic role causing tissue damage in HIV infected patients, particularly by neutrophils, have been reported in multiple studies (12,16,17,31,33,47,48). However, NHP granulocytes in mucosal tissues of chronic SHIV infections have been underexplored.…”

“…Subsequently cells were divided into those that express the CD66 family of receptors (eosinophils, neutrophils) and those that do not (basophils). Next, based on previous reports (16,32,47,48), CD14 was used as a general marker to distinguish neutrophil populations from other subsets and each granulocyte population was defined as follows:…”

“…In humans, CD16 is the preferred cell marker for identifying neutrophils, but NHP neutrophils do not express CD16. Thus, CD14 has previously been used to partially identify NHP neutrophils (16,32,47,48).…”