Related Experiment Video
Updated: Jul 8, 2026

Intraductal Injection of LPS as a Mouse Model of Mastitis: Signaling Visualized via an NF-κB Reporter Transgenic
Published on: September 4, 2012
Kinetics of local and systemic immune cell populations in Staphylococcus aureus chronically infected bovine mammary
Carolina Engler1,2, Silvana Pirola1,2, Camila Beccaria1,2
1Laboratorio de Biología Celular y Molecular Aplicada, Instituto de Ciencias Veterinarias del Litoral (ICIVET-Litoral), Universidad Nacional del Litoral (UNL)/Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Santa Fe, Argentina.
Abstract:
The aim of this study was to evaluate the kinetics of local and systemic immune cell populations in mammary secretions and blood samples from cows free of intramammary infections (IMI) and chronically infected with Staphylococcus aureus during active involution. Cows in late lactation that were either uninfected or with chronic S. aureus IMI were included in this study. The percentages of CD14+ cells in blood samples were significantly higher in S. aureus-infected animals than in uninfected animals at days 7 and 21 post-drying-off. However, the percentages of these cells in the mammary secretions from S. aureus-infected quarters were significantly lower compared with those of the uninfected quarters in all evaluated periods. The percentages of CD4+ cells were similar between uninfected animals and S. aureus-infected animals at all involution times in both blood and mammary secretion samples. The percentages of CD8+ cells decreased significantly in mammary secretions of S. aureus-infected quarters compared with those of the uninfected quarters at all involution stages. The percentages of CD21+ cells decreased in blood samples of S. aureus-infected animals compared with uninfected animals at day 21. In secretion samples, the percentages of CD21+ cells decreased in S. aureus-infected quarters at day 7 compared with those of the uninfected quarters. In conclusion, chronic S. aureus IMI induces a significant increase in the number of CD14+ cells in the blood circulation; however, these cells do not appear to migrate to the mammary secretion being potentially retained in the tissue. Although CD4+ and CD8+ lymphocytes did not vary between S. aureus-infected and uninfected animals throughout involution, the decrease in CD8+ cells in mammary secretion from S. aureus-infected animals suggests that these cells are retained in the mammary tissue, fulfilling their specific functions to eliminate intracellularly infected cells. The low number of CD21+ lymphocytes in mammary secretions of infected animals would reduce the humoral defence potential of the gland.
Related Concept Videos
Clinical Significance of Antibiotic Resistance
Acute Inflammation III: Local and Systemic Effects
Chronic Inflammation: Introduction

