IFNAR1 Deficiency Impairs Immunostimulatory Properties of Neutrophils in Tumor-Draining Lymph Nodes.

Tumor-draining lymph nodes (TDLNs) are the first organs where the metastatic spread of different types of cancer, including head and neck cancer (HNC), occurs and have therefore high prognostic relevance. Moreover, first anti-cancer immune responses have been shown to be initiated in such LNs via tumor-educated myeloid cells. Among myeloid cells present in TDLNs, neutrophils represent a valuable population and considerably participate in the activation of effector lymphocytes there. Tumor-supportive or tumor-inhibiting activity of neutrophils strongly depends on the surrounding microenvironment. Thus, type I interferon (IFN) availability has been shown to prime anti-tumor activity of these cells. In accordance, mice deficient in type I IFNs show elevated tumor growth and metastatic spread, accompanied by the pro-tumoral neutrophil bias. To reveal the mechanism responsible for this phenomenon, we have studied here the influence of defective type I IFN signaling on the immunoregulatory activity of neutrophils in TDLNs. Live imaging of such LNs was performed using two-photon microscopy in a transplantable murine HNC model. CatchupIVM-red and Ifnar1-/- (type I IFN receptor- deficient) CatchupIVM-red mice were used to visualize neutrophils and to assess their interaction with T-cells in vivo. We have evaluated spatiotemporal patterns of neutrophil/T-cell interactions in LNs in the context of type I interferon receptor (IFNAR1) availability in tumor-free and tumor-bearing animals. Moreover, phenotypic and functional analyses were performed to further characterize the mechanisms regulating neutrophil immunoregulatory capacity. We demonstrated that inactive IFNAR1 leads to elevated accumulation of neutrophils in TDLNs. However, these neutrophils show significantly impaired capacity to interact with and to stimulate T-cells. As a result, a significant reduction of contacts between neutrophils and T lymphocytes is observed, with further impairment of T-cell proliferation and activation. This possibly contributes to the enhanced tumor growth in Ifnar1-/- mice. In agreement with this, IFNAR1-independent activation of downstream IFN signaling using IFN-λ improved the immunostimulatory capacity of neutrophils in TDLNs and contributed to the suppression of tumor growth. Our results suggest that functional type I IFN signaling is essential for neutrophil immunostimulatory capacity and that stimulation of this signaling may provide a therapeutic opportunity in head and neck cancer patients.

RESPUESTA CELULAR PRODUCIDA POR UNA INFUSIÓN DE Bursera sp / CELLULAR RESPONSE PRODUCED BY A Bursera sp INFUSION

Introducción: determinar los niveles de eosinófilos, linfocitos y neutrófilos producidos con una infusión de la planta medicinal Bursera sp. Materiales y métodos: se seleccionaron cinco individuos sanos. Se determinaron porcentajes de células blancas iniciales por hemoleucograma. Luego se les suministró una toma diaria de 5 g de la corteza del árbol Bursera sp, previo consentimiento informado. Posteriormente, se les realizó hemoleucograma a los 17 días (primer muestreo) y a los 31 días (segundo muestreo). Resultados: en la mayoría de los casos se cumple que al umentar los eosinófilos y los neutrófilos, los linfocitos permanecen bajos. Discusión: estos resultados pueden indicar un efecto inmunomodulador de la infusión de la planta Bursera sp, especialmente sobre los linfocitos, mostrando a esta planta como una alternativa terapéutica para la inmunología de los trasplantes y en enfermedades autoinmunitarias, ya que se apreció una disminución de linfocitos cuando los neutrófilos y eosinófilos aumentaron; debido a la muestra pequeña así como a la adherencia incompleta de algunos de los individuos del estudio, es pertinente realizar estudios con una mayor muestra y con análisis adicionales, como inmunoglobulinas séricas y citometría de flujo, para determinar si la disminución de los linfocitos afectó a los Linfocitos T, B o ambos.

Introduction: to determine the levels of eosinophils, lymphocytes and neutrophils produced with the Bursera sp. medicinal plant infusion Materials and methods: five healthy individuals were selected. Initially, white cells percentages were determined by cell blood count. Then, previous informed consent, hey were given a daily intake of 5 g of Bursera sp tree bark. Subsequently, cell blood count was performed after 17 days (first sampling) and after 31 days (second sampling). Results: in most cases the increase in eosinophils and neutrophils, lymphocytes remained low. Discussion: these results may indicate an immunomodulatory effect of Bursera sp infusion especially on lymphocytes, showing this plant as a therapeutic alternative for transplant immunology and in autoimmune diseases since a decrease in lymphocytes was noticed when neutrophils and eosinophils increased. Due to the small sample and incomplete adherence to some of the individuals in the study, it is relevant to carry out studies with a larger sample and additional analysis such as serum immunoglobulins and flow cytometry to determine whether the decrease of lymphocytes affected the T lymphocytes, the B ones or both.