Response Of Bovine Mammary Gland Research Articles

Aspectos de la respuesta inmune innata en las infecciones intramamarias causadas por Staphylococcus aureus en bovinos

Staphylococcus aureus is the pathogen most frequently isolated from bovine mastitis worldwide, causing chronic intramammary infections that limit profitable dairying. The objective of this article is to characterize the mechanisms involved in S. aureus mammary gland infections considering two different aspects of the infectious process; on the one hand, the aspects involved in the host innate immune response and on the other hand, the capacity of this organism to evade the immune system and interact with different cell types. The exploration of S. aureus interactions with the immune response of bovine mammary gland will help identify targets to outline new preventive or curative alternatives for intramammary infections caused by this organism.

Expression of macrophage CD44 receptor in the course of experimental inflammatory response of bovine mammary gland induced by lipopolysaccharide and muramyl dipeptide

The aim of this study was to investigate development over time of the surface expression of CD44 on macrophages during an inflammatory response of bovine mammary gland. Intramammary instillation of muramyl dipeptide (MDP) and lipopolysaccharide (LPS) resulted in a significant increase in the total count of CD44+ non-vacuolised macrophages ( NMAC) after 24 h. During resolution of the inflammatory response, there was observed a gradual decrease in the total count CD44+ NMAC. The lower total count and proportion of CD44 + vacuolised macrophages ( VMAC) was observed as the effect of MDP and LPS at 24 h after induction ( P < 0.01). During resolution, the total count and proportion of CD44 + VMAC increased. We have demonstrated CD44 receptor is expressed during the inflammatory response caused by LPS and MDP and the effect of these components on CD44 expression was particularly evident during initiation of the inflammatory response. High expression of CD44 in resolution of inflammatory response may relate to macrophages´ involvement in the processes leading to restitution of injured tissues.

Innate immune response of bovine mammary gland to pathogenic bacteria responsible for mastitis

Mastitis (mammary gland inflammation) is one of the most important bovine diseases causing economic losses to dairy producers. Mammary gland inflammation is a consequence of the activity of a number of cell and soluble factors that function together to eliminate invading microorganisms. The factors involved in this inflammatory response differ depending on the infectious agent. This review analyzes the factors involved in the immunologic mechanisms against the main pathogenic bacteria causing mastitis, and emphasizes the innate immune response of the mammary gland. Knowledge, at the molecular level, of the mammary gland immune response during infection by pathogenic bacteria is fundamental to the design of effective therapies to control and eradicate bovine mastitis.

Role of several Staphylococcus aureus virulence factors on the inflammatory response in bovine mammary gland

Staphylococcus aureus causes many serious diseases in humans and animals, and it is the most common aetiologic agent of contagious bovine mastitis. The bacteria produce several virulence factors and the importance of evaluating the combination of these virulence factors has been recently emphasized. In study, the combination of several virulence factors: coagulase gene ( coa), protein A gene ( spa), collagen-binding protein gene ( cna), fibrinogen-binding protein gene ( efb), Panton-Valentin leukocydin gene ( pvl) and enterotoxins ( sea, seb, sec, sed, see, seg, seh, sei, sej) was considered. The analysis of the relationship between presence/absence of the different genes and the udder inflammatory response measured by milk somatic cell counts was performed by general linear models and logistic regression. The classification of isolates in clusters by virulence genes combinations showed that at least one cluster induced a higher inflammatory response. Moreover, the analysis of the association between virulence genes and the presence of a subclinical mastitis showed the role of spa and sej gene as risk factors. These results support that the development of subclinical mastitis could be related to strains characteristics and to the expression of specific combinations of the virulence factors.