Neutrophil dynamics in the blood and milk of crossbred cows naturally infected with Staphylococcus aureus

Aim: The present study was designed to evaluate the neutrophil dynamics in terms of the functional competence during subclinical mastitis (SCM) and clinical mastitis (CM). Materials and Methods: A total of 146 Karan fries cows were screened and were divided into three groups as control (n=12), SCM, n=12 and CM, n=12 groups on the basis of California mastitis test scoring, bacteriological evaluation, gross and morphological changes in milk and by counting milk somatic cell count (SCC). Both blood and milk polymorphonuclear neutrophils (PMNs) were isolated in the study. Phagocytic activity (PA) was studied by spectrophotometrically; neutrophil extracelluar traps (NETs) were studied by scanning electron microscopy (SEM); CD44 was quantified by flow cytometry and apoptosis was studied by fluorescent microscopy. Results: Significantly (p<0.05) higher SCC, PA was found in milk of CM cows as compared to SCM and control cows. Significantly lower (p<0.05) apoptosis was observed in PMNs isolated from both blood and milk of CM group of cows when compared to control and SCM group. The milk neutrophils of CM group of cows formed NETs as evidenced from the SEM images. Surface expression of CD44 revealed a significantly (p<0.05) lower expression in milk neutrophils of CM group of cows when compared to SCM and control group of cows. Conclusion: The study indicated a positive correlation between delayed neutrophil apoptosis, persistent staying of neutrophils at the site of infection along with formation of NETs as the strategies to fight against the pathogens in the udder during Staphylococcal mastitis. The study forms a strong base for future molecular research in terms of neutrophil recruitment and neutrophil removal from the site of infection

Surface expression of CD11b, CD62L, CD44 receptors on blood and milk neutrophils during subclinical and clinical mastitis in Sahiwal cows

Surface expression of cell adhering molecules and CD44 was studied in Sahiwal (SW) cows suffering naturally from subclinical (SCM) and clinical mastitis (CM). Cows were divided into groups, viz. healthy (12), SCM (12) and CM (12) groups on the basis of CMT scoring, bacteriological culture, gross morphological changes in the milk and by counting milk SCC after screening of 136 SW cows. Bacteriological culture indicated infection of Staphylococcus aureus as the causative agent of SCM and CM. Healthy cows showed significantly higher CD62L expression as compared to the SCM and CM group of animals in both blood and milk neutrophils but no significant difference was found between blood and milk neutrophils. The results revealed a significant upregulation of CD11b positive cells in the CM group of cows. Significantly higher expression of CD44 was found in the neutrophils of both blood and milk of SCM group as compared to CM group. From the study, it was evident that neutrophils exhibit dynamic interplay between the integrins (CD11b) and selectins (CD62L) along with CD44 during SCM and CM Staphylococcal mastitis to offer host protection against the foreign invaders

Neutrophil surface adhesion molecule and toll like receptor dynamics in crossbred cows suffering from Staphylococcus aureus subclinical and clinical mastitis

Objective: The present study was an attempt to delineate the roles played by the neutrophil surface adhesion molecules and toll like receptors (TLRs) in crossbred cows suffering from Staphylococcus aureus subclinical and clinical mastitis. Materials and methods: Thirty six Karan Fries (KF) cows were categorized into three groups namely healthy (n=12), subclinical mastitis (SCM; n=12) and clinical mastitis (CM; n=12) after screening 146 cows. The grouping was done based on evaluation of collected milk samples by routine procedures like Californian Mastitis Test (CMT) scoring, microscopic counting of milk cells (SCC), bacterial culture of milk samples and observing gross changes in milk. Culture of milk and blood was done for the identification of Staphylococcus aureus subclinical and clinical mastitis. Results: Healthy cows expressed significantly (P<0.05) higher L-selectin (CD62L) in both milk and blood neutrophils as compared to the animals suffering from SCM and CM; however, no significant difference was noticed between milk and blood neutrophils. Significant (P<0.05) increase in the expression of beta integrin (CD11b) was observed in the CM group of cows as compared to SCM and healthy cows. Similar trend in the expressions of TLR2 and TLR4 in both blood and milk neutrophils was observed in the CM cows as compared to the healthy and SCM cows. Milk neutrophils revealed a higher expression of TLR as compared to blood neutrophils. Conclusion: Host elicits stage specific expression of surface adhesion molecules and TLR2 and TLR4 as dynamic host innate immune response against Staphylococcal mastitis. [J Adv Vet Anim Res 2016; 3(2.000): 99-105